New aspects of mineral and water resources in The Netherlands

NEW ASPECTS OF MINERAL AND WATER RESOURCES IN THE NETHERLANDS

Deel 29, 1973

Verhandelingen

van het

Koninklijk N ederlands geologisch

mijnbouwkundig

Genootschap

New aspects of mineral and water resources in The Netherlands

Editors: l.W.C.M. van der Sijp H. Boissevain A.A. Thiadens E. Romijn

ISBN 978-94-017-7092-7 ISBN 978-94-017-7129-0 (eBook) DOI 10.1007/978-94-017-7129-0

CONTENTS

G.l. Krol: Introduction 7

A. Hols: The future energy supply in The Netherlands 9

W.F.M. Kimpe: The geology of the Carboniferous in the coalfield Beatrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 19

J.A.A. Ketelaar: Salt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 37

H.M. Harsveldt: Middle Triassic limestone. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 43

W.M. Felder: Kalkstenen van het Boven Krijt in Zuid Limburg. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 51

H.M. Harsveldt: The discovery of uranium at Haamstede 63

O.S. Kuyl: Pure Miocene quartz sands in southern Limburg 73

E.Oele: The gravel and sand supply in The Netherlands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 81

W.H. Zagwijn and H.M. Harsveldt: Peat deposits and the active carbon industry' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 85

G.W. Putto: The law and management of ground-water resources. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 89

E. Romijn: Ground-water resources in The Netherlands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 91

J.B. Breeuwer and S. Jelgersma: An E-W geohydrological section across The Netherlands ..................................... 105

INTRODUCTION

On the occasion of the sixtieth anniversary of our Society the General Assembly held in The Hague on March 18th 1972 was combined with a symposium entitled: "Enkele nieuwe aspecten van delfstoffen in Nederland."

The programme was as follows:

Mr. G.W. Putto "Grondwater als grondstof van de drinkwatervoorziening"

Prof.Dr. J.A.A. Ketelaar "Zoutgebruik, nu en in de toekomst"

Dr. E. Oele "Voorkomen en toekomst van de winning van industriezand en -grind"

Ir. A. Hols "De toekomstige energievoorziening in Nederland".

Moreover it was decided to devote to this subject an issue of our proceedings in which the contributions to this symposium should be published with the addition of other topical papers.

I am happy to notice that so many authors have responded to our request so that indeed the latest data in so many fields have been collected in this proceeding.

I like to express my gratitude to the "Commissie van de Europese Gemeenschap", "Shell Nederland B.V." and "Nederlandse Staatsmijnen DSM" for their financial support to this issue.

A vote of thanks is due to the authors and to the members of the editorial committee who have devoted so much of their time and effort to this Anniversary Volume.

G.L. Krol

VERHANDELINGEN KON. NED. GEOL. MIJNBOUWK. GEN. VOLUME 29, p. 9-18, 1973

THE FUTURE ENERGY SUPPLIES TO THE NETHERLANDS

A. HOLS I )

SUMMARY

The future satisfaction of mankInd's Increasing energy demands IS a popular subject of discuSSIOns in the press, academic cucles and government agencIes. The much publiCIzed energy gap foreseen in the United States has led to a multItude of studies being undertaken: Japan IS worrying about their future energy sources and Western Europe is becoming aware of the fact that the era of abundant and cheap energy may be a thing of the past.

SInce World War II, the Netherlands have seen the rapid transItIOn from a coal-based economy, through an OIl-based energy balance, to the era of natural gas. The resulting wide-spread and significant upheavals of a SOCIal and economIC nature are wel1 known. We, Western Europeans, realize that the world's Inventory of fossil fuels IS certaInly not unlimited and that we will be very dependent for our Pnmary energy requirements on MIddle Eastern and North Afncan. hydrocarbon resources for quite a whIle yet.

An attempt to forecast the satIsfaction of the energy demands of the Netherlands and the role hydrocarbon resources from European origIn may play In the energy package, is the subject of this paper.

INTRODUCTION

The subject of this paper concerns the world's and therefore our future energy supplies, a problem which is becoming increasingly topical, in view of the rapidly increasing consumption of energy2 in the developed countries and the political and economic effects of the predominant position of the big exporting countries.

One of the more popular topics in the USA today is the "energy gap". We must realize, however, that this domestic problem is largely of their own making, mainly as a result of the following actions which tend to discourage rather than encourage the hydrocarbon industry: - control of oil imports

I) Shell InternatIOnale Petroleum MaatschapPIj B.V., Carel van Bylandtlaan 30, The Hague, The Netherlands

2) In this paper the term "energy" Includes both electncIty and fuels, not just "energy" generated as electricity, a term which is common use In Western Europe.

control of gas prices (while not controlling prices of alternative fuels) legislation on fuel qualities for environmental reasons tough health regulations in coal mines environmental objections to development of alternatives to conventional coal and hydrocarbon resources, such as oil shales, offshore crudes and surface-mined coal.

Europe's present prosperity is mainly energy-based; the Europeans are becoming used to a limitless supply of cheap energy to fuel the industries and to cater to their comforts. However, there are voices in Europe that do not see or do not want to see that Europe's dependence on imported fuels should be taken seriously. Fiction is spread around that European gas, gas imported overland from Russia or by tanker as LNG, and North Sea oil as well as accelerated nuclear developments will take care of Western Europe's problems comfortably.

This paper intends to discuss and rationalize the hydrocarbon components of the various energy factors, to get some insight in Western Europe's and the Netherlands' future energy picture.

The basic information presented can be found in literature; a list of consulted publications and studies follows the paper. The author will De the first to admit that the basic information is highly debatable and mostly out of date already; we are dealing with a dynamic subject, of a continuously changing picture. The paper covers in principle the next 15 years, although some projections to the year 2000 are presented. Forecasting is a difficult thing and one can only derive some sensible figures for the next 15 years in the context of the subsequent period about which, of course, one knows even less. In forecasting the picture of the next 15 years we can use the experience of the 1960's and although we all know that history never repeats itself, one can learn from the way in which demand and supply for energy developed in the recent past. Although it is the intention to focus on our domestic problems, pictures of the world as a whole have to be studied before dealing with Western Europe. In the paper the "world" will be limited to the "world outside

10 A. HOLS

the Communist areas", not only because we know very little TABLE I about what is going on inside the Communist world, but also TYPical Growth Rates.

because it can be argued that they will not have much influence on the energy balance of the so-called "Free

per cent per year

Est. World". 1940/50 50/60 60170 70/80

UNITS

All volumes and rates have been expressed as much as possible in term of barrels of oil equivalent and days. The "barrel of oil" and "barrels per day" are the most frequently used units in the international oil business, although not popular in Europe, where tons of oil per year or tons of coal equivalent per year are in vogue. Furthermore, for oil a billion means 109 in the American way, but when talking about gas the European denomination of 109 , a milliard, has been used.

GROWTH

Especially in the Netherlands, the problem of growth is a popular subject of debate. By April 1972 the Club of Rome Report had sold more copies in Holland than in the rest of the world combined. Some historical growth rates of energy demand in the world outside the Communist areas are shown on table 1. Free World energy consumption grew by 2~% per annum in the immediate post-war era, 3~% in the 1950's and 5% per annum in the 1960's. This is called exponential growth, a certain percentage per year. Extrapolation of exponential growth into the future, not only for energy consumption but also for such items as population and pollution, has led to the concerns of, for instance, the Club of Rome and serious implications are predicted if all growth were to continue to increase exponentially. As no kind of growth can continue indefinitely, certain parameters influencing world energy demand can be expected to change in the long term future. This is, of course, subject to extensive speculation and discussion, but as long as one can see no real reason to doubt exponential growth in energy consumption in the near future, the following forecasts are based on this assumption. Just what exponential growth means is well illustrated on fig. 1. The lower curve represents a linear extrapolation of the world oil growth curve from the perspective of 1962, before continued exponential growth was recognized. Comparison with what actually happened gives us an idea of what exponential growth means in realistic terms.

Why is the consumption of energy growing as fast as it does? The main uses of energy are:

household (comfort) industry transport (air, ground, sea)

In the above, the use of electricity is the fastest growing_ Growth in energy consumption is mainly due to:

Free world energy

Free world 011

Western Europe populatIon

Western Europe GNP

Western Europe electroclty

Western Europe energy

Netherlands energy

Netherlands electro CIty

Netherlands home electro CIty 1 capita

MBOE/Q 60

50

40

30

WORLD OIL DEMAND

5\1, % AAI

.~:62 ESTIMATE

4

1

LINEAR EXTRAPOLATION 20

10

5

7-8

<1

4.8

8

8

7%

8)1,

O+---------r--------,---------r------~~ 1960 1965 1970 1975 1980

Fig. I Exponential Growth Rate.

TABLE 2 Oil Resource Requirements.

all data in billion barrels

Oil consumed Reserves reqUIred year end

5 year Cumulative (Cumulative produclJon on penod from 1.1.71 1. 1. 71: 220 bilhon bbls)

1971- 75 80 80 1975 25 yrs 475

1976- 80 107 187 1980 20 yrs 475

1981· 85 133 320 1985 16 yrs 475

1986- 90 165 485 1990 15 yrs 550

1991- 95 205 690 1995 15 yrs 675

1996-2000 255 945 2000 15 yrs 835

Reserves to be proven br 2000

945 + 835 = 1780

Proven Reserves 1.1.71 550

To be added 1230

or 41 billion bbIsIyr

5

4.3

6-7

THE FUTURE ENERGY SUPPLIES TO THE NETHERLANDS 11

increased industrial activity affluent societies in the developed countries (comfort, sophistication) increasing leisure time (boating, travelling) diminishing increases in efficiency in the use of resources anti-pollution measures low cost prevailing so far.

However, forecast on the basis of rapid growth may be too optimistic on account of:

ecological awareness sustained economic recession

- rapidly increasing prices of resources actions on production rates by the major exporting countries breakthroughs of more efficient uses of energy

FORECASTING

How are demand forecasts arrived at? In fig. 2 the relationship between energy consumption and gross national product of several nations is shown. One could say that a trend exists which is preferably used to forecast energy demand from predictions of gross national product, assuming that the GNP can be reliably predicted. One demand forecast, as for instance world energy demand (fig. 3) was put together on this basis. The next problem concerns the supply to meet this energy demand, and the role by future requirements for hydrocarbons. Energy demand is met by the following principal resources: oil, coal, natural gas, hydro- and nuclear electricity expressed in this paper in terms of the common denominator of millions of barrels of oil equivalent per day. By assessing as well as possible the future availability of hydro power (which is simple), nuclear electricity (which is mainly constrained by industrial capacity, costs and knowhow) and solid fuels (mainly constrained by competition of hydrocarbons) the remaining gap must be filled by hydrocarbons. As a result one sees that of the total 1970 energy demand of the world outside the Communist areas of 66 mbdoe* oil supplied 35 mbdoe; for 1980 these figures are 110 mbdoe energy and 65 million barrels of oil fuels, in 1985 140 mbdoe and 80 mbd of oil fuels respectively. Comparable figures for Western Europe will be discussed later, but first the resource bases from which the world must draw its supplies will be investigated. In this paper only crude oil resources will be dealt with for the following reasons.

Although natural gas plays an important role in the world energy picture, it has been, and in the future will be, only a fraction of no more than, 20 to 25% of the oil supply and demand. Natural gas is amply available world-wide but at present only a relatively small fraction is of economic value, although it generally is very profitable when found close to major consumption centres. Relative to crude oil, natural gas

*) mbdoe = million barrels per day of 011 eqUIvalent.

ENERGY PER CAPITA (MILLIONS OF BTU)

200

150

CANAOA •

• UNITED KINGDOM

100

• GERMANY

USSR.

• FRANCE

• JAPAN

• SPAIN

• BRAZIL

o • INDIA

o 1000 2000

GROSS NATIONAL PRODUCT PER CAPITA (DOLlARS)

Fig. 2 Energy Use vs. Gross NatIOnal Product.

MBOE/D 140

120

tOO

80

60

40

20

0 '950

Fig. 3

'55

WORLD ENERGY BALANCE EXCLUDING COMMUNIST COUNTRIES

'60

World Energy Balance 1950-1985.

USA.

3000

NUCLEAR HYDROPOWER

NAT GAS

OIL

COAL

is subject to high processing and transportation costs in order to bring it to the major consuming centres. Since gas occupies a greater volume than oil for the same heat content, a gas pipeline can transport only 20 to 30% of the useful energy carried by a crude oil pipeline of equal size, while the cost of an LNG tanker per unit of energy shipped may be four times that of an equivalent crude·carrier. These are formidable obstacles since it is self-evident that the further one wishes to move gas, the more severe the cost disadvantage becomes. As it is the competition between alternative energy sources at the customers' end that will decide which fuel will prevail, transportation costs play a very significant role.

12 A. HOLS

RESOURCE BASE

Because one can only study the period to 1985 in the context of a longer period in time, the requirements and reserve position up to the year 2000 will also be discussed. Extrapolating the world oil demand (fig. 3) to the year 2000, table 2 was prepared on which, for different points in time, oil resources required to satisfy demand and the reserves needed in order to guarantee future requirements are shown.

A parameter essential for this type of forecast is the often quoted reserve over production ratio. The conventional way of quoting this ratio is the number of years that production could be continued at the existing rate from the proven resources. Good oil-field practice requires this to be not less than, say, between 10 years in highly developed areas and 15 years in less developed areas . Reserve over production ratio quotes can be misleading if not properly understood. In times of exponential growth in demand, the number of years of actual production remaining are much less than the years quoted at "current" production rate. This is very significant as it shows the influence on a forecast of exponential terms.

In fig. 4 the "proven" oil reserves over current production ratio, in years, for the Free World for the last 15 years is shown. It was very high, from 55-65, before it started to decline to the 35 years of today. However, in terms of years of forecast production this ratio drops to 20 years. Evidently the world is demanding oil at a rate which growths faster than at which it is finding new resources. Assuming that the reserve over production ratio is to continue to decline and to level off at about 15 years by 1985, one arrives at the right hand side of table 2. If the world is to maintain a reserve over production ratio of 15 years until the end of the century, more than 40 billion barrels of oil will have to be discovered every year in order to satisfy demand and to maintain sufficient reserves. According to recent studies of the U.S. National Petroleum Council the average finding rate of the Free World has been 15 billion barrels during the last 15 years. On the other hand, world reserves are also being boosted by increased recovery efficiency from known oil wells (fig. 5). The combination of discovery rate and the possibility to obtain more oil from sources already proven has resulted in additions to the Free World's oil resources of about 30 billion barrels per year during the last 15 years according to the U.S. National Petroleum Council.

The data from table 2, i.e. the oil requirements of the Free World and the reserves needed at the end of each period, are presented in a graphical form in fig. 6. By the year 2000 some 1200 billion barrels of oil would have to be added to today's 533 billion barrels of proven oil (as quoted by the Oil and Gas Journal). Proven oil, as discussed so far, is the amount, with some variations of course, that industry believes will certainly be produced in terms of today's economics. Moreover, one must of course think in terms of expectations of oil still to be discovered or recovered additionally from already proven accumulations. Many experts have looked at this problem and many different

ASSUMED TREND OF FUTURE INDUSTRY RIp RATIO FOR OIL

FREE WORLD

70~----~----r-----.-----.-----r---~

50

~ 40 ~ Q

~ 30 .. i<

20 -

10

0 t955 1960

Fig. 4 Oil Reserve/Production Ratio Trend.

USA CUMULATIVE RECOVERY EFFICIENCY

Fig. 5 Trend Recovery Efficiency USA.

WORLD LIQUID HYDROCARBON REQUIREMENTS AND RESOURCES

All data In Billions of Barrels 011 Equivalent

ca COAL* 4000 [[l]]]]J OIL S""LES

CJ TAR SANOS ~ OEEPSEA I:::l ExPECT. CONVENTIONAL SOIJRCES _ PROVEN RESERVES

3000 * COAL FOR CONVERSION OR DIRECT REPL.ACEMENT

2000

1000

o

Fig. 6

OF LIQUIO fUELS fOR POWER GENE;RATtOH

o RESERVE RATIO REOUIREMENTS

\-=< CUMULATIVE OIL CONSUMEO

Free World LiqUid Hydrocarbon Requirements and Resources.


figures have been and are continuously being published in literature.

First of all we consider the expectations from areas currently productive on land and the continental shelves, a range from 300 to 870 billion barrels as shown in the two columns on the left-hand side of fig. 6.

The next category is the "conventional oil" from areas not yet productive and for which techniques are not yet available, such as from the Artic and the deep oceans, which are shown with nominal amounts ranging from 100 to 200 billions of barrels. As this is purely speculative oil one cannot argue as yet about the validity of these quantitative assumptions but a statistical approach could lead to figures of this order. Much higher figures are sometimes mentioned, but these could only be justified by, at the same time, visualizing crude costs far in excess of what today we feel should be the limit. Something we do know, however, is that industry is undertaking a gr~at deal of effort to develop techniques to explore for and develop conventional hydrocarbons from these "new frontiers".

Oil shales and tar sands are frequently referred to in literature as the panacea to resource problems. In fig. 6 the ranges are shown that have recently been quoted after intensive studies by the U.S. National Petroleum Council (who have been charged with an in-depth study of the long term world energy resources but from a United States' requirements point of view). Although data on very high oil shale reserves are often mentioned in literature, they are generally neither related to economics nor to the ecological consequences of their development. However, one must of course always think in terms of costs (and environment) as long term competition in the energy market will be governed by economic factors. There must be a limit to the amount of money (and pollution) one can afford to run the industry and be comfortable. Here we are reaching the most difficult and unexplored field of uncertainty in long term energy forecasting of energy supply.

Coal reserves are often mentioned as being extensive and a good raw material for the manufacture of synthetic crudes and synthetic gases. A range of synthetic crudes that could be manufactured from coal at possibly economically attractive terms is therefore shown. These are "alternative" resources, that will playa role in the future.

The measure from this illustration is that, from what one can see with certainty today, the proven reserves, the world will not be able to draw on for too long. Additional, yet to be proven and certainly much more expensive resources will play a role if the world is going to enjoy increasing energy consumption to the end of the century.

GEOGRAPHY OF RESOURCES

While there is no doubt that for, say, the next 10 to IS years proven reserves of liquid hydrocarbons are quite sufficient to meet an acceptable reserve over production

ratio, the geographical distribution of hydrocarbon resources is a problem. Of the proven conventional oil resources, the Middle East has by far the largest share. However, in the long run and considering alternative sources of hydrocarbons, it is the North American continent that will be in the relatively stronger position. The major tar sand reserves are located in Canada (and Venezuela), shale oil reserves in the USA (and Brasil), while the main part of the easily mineable coal is found in the USA.

Leaving Russia and China out of consideration, it can be concluded that the world's proven oil reserves will have been consumed before 1985 and new sources of conventional crudes will have to be found all over the world, in the Middle East, the North Sea, the Arctic and in the deep sea. In addition we can count on unconventional crudes from tar sands and oil shales as well as the synthetic hydrocarbons that can be manufactured from coal. Whether liquid or gaseous fuels will be preferentially manufactured from the last three remains to be seen. This is again a question of economics, the economics of manufacturing and transportation; however, these fuels can be considered for the long term as part of the oil package.

It is clear that, certainly during the next 10 to 15 years, the world's oil supplies for the importing areas such as North America, Western Europe and Japan will be dominated by Middle Eastern (and North African) crudes, whereby North America does have domestic alternatives in synthetic fuels, the availability of which, although requiring a considerable amount of capital, can be encouraged by the Federal Government. Middle Eastern crudes will play an important role in North America but they will occupy an increasingly dominant position in Western Europe and Japan. That this is realized by the OPEC countries is clear from an interview given by a senior OPEC official in early 1972* who said: "If I were the consumer looking down the road to 1980, I would feel rather scared that sometime in the 80's I would not be able to find enough energy around to keep my industries going, that my factories might run down and that my gasoline pumps might dry up because I have lost my security of supply. We are facing a new era now."

WESTERN EUROPE

The supply and demand position of Western Europe as shown on figure 7 represents the most likely interpretation from a number of forecasts made by experts. The role of coal is expected to decrease continuously. This is not only a matter of relative economics, but also of the basic sociological problem of underground mining. European coal is almost totally mined underground with low productivity per man when compared to US underground mines. European coal is therefore already expensive, relative to competitive

*) Evemng Standard, London, 18th January 1972, front page.

14 A. HOLS

WEST EUROPEAN ENERGY BALANCE INCLUDING UNITED KINGDOM

MBOE/D 40

30

20

10

/0 NUCLEAR

HYDROPOWER

f4~ NAT GAS

OIL

COAL O+---~----~--~----~--~----.---~

1950 '55 '60 '65 '70 '75 '80 '85

rig. 7 Western European Energy Balance.

TABLE 3 Western European Hydrocarbon Resources.

* MER BOD means maximum efficient rate 111 barrels 011 per day

WESTERN EUROPE RESOURCES

Oil RESERVES,tO' BBlS MER BOD

Proven + EXPte~~~ ~y semi proven

N.SEA N.SEA

NORWAY 2,000 7,000 1976 1,000,000 U.K 4,500 9,500 1980 2,600,000

REST 500 1,000 1985 4.000,000

7,000 17,500

RESTEU 1,500 2,500 1985 aoo,ooo TOTALEU 8,500 20,000 1985 4,800,000

GAS- ULTIMATE RECOVERY (as saen early 80's)

109 m3 Billion bbls oil eq.

1. NON-ASSOC NETH LD PROVEN-EXPECTED 2,300 10.0 2 NON-ASSOC U.K NORTH SEA PROVEN-EXPECTED = 1,100 5.0

3.ASSOCIATED UK- NORWAY PROVEN_EXPECTED . 1,000' 4.6 4.REMAINDER NORTH SEA PROVEN _ EXPECTED 400 1.9

4,800 21.5

5 REST OF EUROPE(GERMANY,FRANCE,ITALY,l,RES. lPOO 4.8

5,800 26.3

• BASED ON QL EXP£CTATlONS OF 17 ~ BILliON 88LS AND ASSUMED sM OF 2000 CFB

sources of energy and as there will be increasing reluctance to send people down the mines, it is difficult to foresee an increase in tonnage mined by underground labour.

Nuclear and hydropower have been given the maximum foreseeable growth; the difference therefore goes to hydrocarbons, of which oil will continue to be the dominant energy source in Western Europe, although natural gas will grow in importance.

To deal briefly with Europe's resources of oil and gas, the latest information on Europe's oil reserves are shown on table 3. Although these figures are by no means certain, they are of interest in assessing the contribution these resources can make to the European energy demand picture during the next IS years.

As far as oil is concerned, and leaving the North Sea area aside for a while, there are still exploratory possibilities remaining in Western Europe, on land and on the continental shelves. In total, however, they are insignificant by world standards. They might generate a million barrels per day in 10 to 15 years from now but that is pure speculation.

The North Sea area, however, is considered to be highly prospective and, supposing that some 17'12 billion barrels might be proven before 1980 (Le. another 11 billion barrels above what today are called "proven and therefore commercially exploitable" reserves), one might conclude that this could lessen Europe's dependency on Middle Eastern resources. Without going into details on the effort required, how long and how much money it will take to develop North Sea reserves of the order indicated, the financial requirements will be very high indeed. But even if the capital and manpower are forthcoming, 17 to 18 billion barrels of reserves will provide Europe with no more than, say, 4 to 4'12 million barrels per day by 1985 which represents some 20% of Western Europe's oil demand, or some 10% of its total foreseen energy demand.

Turning to natural gas, this commodity meets Europe's energy demands today for about 10% and this figure is expected to increase to some 14% by 1985 (fig. 7). Some figures for Western European gas reserves as can be envisaged today are also shown on table 3. The Netherlands' reserves of some 2300 milliard m3 (equal to 80 trillion cu.ft), mostly from the Groningen gas field, figure on top of the list.

The figures shown on the next line (U.K. North Sea) are based on published information of 40 trillion cu.ft ultimate recovery. Norway's Ekofisk gas field is estimated at 7 trillion cu.ft and assuming a very liberal gas - oil ratio another 50 trillion cu.ft are indicated (lines 3 and 4). As a result one can foresee that the gas reserves in the North Sea area (including the '~etherlands land) will be in the order of 4800 milliard m3 or some 170 trillion cu.ft (give or take 10-20%), which is equivalent to about 22 billion barrels of oil. In terms of energy this is more significant than the oil resources shown on the same table, but hardly a major reserve by world standards.

With these figures in mind one can speCUlate about the supply possibilities to meet the demand which is shown on fig. 7. A future gas balance prognosis is shown on table 4 and fig. 8; a very liberal gas availability forecast for Western Europe over the next 15 years, culminating in 340 milliard m3 per year (35,000 MMcfd or 5.4 million barrels of oil equivalent per day) by 1985, which amounts to 14% of Western Europe's foreseen energy demand.

The question is often asked why industry would not draw faster from the domestic natural gas resources available to Western Europe. Table 4 shows a rate of some 230 X 109 m3

in 1985 from 5800 milliard m3 of total gas reserves. This is certainly not overly conservative. The physical limit of what the giant Groningen field can produce has recently been published; it is in the order of 82'12 milliard m3 per year to be reached in 1975-1976. This plateau rate can hopefully be


TABLE 4 Western European Gas Balance.

GAS BALANCE WESTERN EUROPE INCL U K

109 m 3 per year

1971 1975 1980

1 Netherlands Land 43 80 95

2 North Sea' U. K 16 30 40 North Sea. Other 10 20

3 Rest Europe 35 40 45

4 Imports RUSSIA 2 15 35 LNG 2 10 25

100 185 260

~ mooed 16 30 42

WEST EUROPEAN GAS SUPPLY INCWDING UNITED KINGDOM

GAS SUPPLY

109 M3/YR 6 MBOE/D

350

300

250 4

IMPORTS

200

ISO

100

50 NETHERLANDS

1985

90

50

50

40

70 40

340

54

O~.---------.---------.-------~ 1970 '75 '80 '85

Fig. 8 Western European Gas Supply

maintained over a number of years. The total production from the Netherlands gas fields on land of 95 milliard m3 per year in 1980 is therefore a realistic figure.

Assuming that the European domestic availability of 230 x 109 m3 per year in 1985 is about right, there will at that time be a need for imports of some 110 milliard m3 per year, by no means a conservative figure and much higher than most forecasts presented today.

Present contracts call for 36 milliard m3 per year of gas from Russia by 1980, to be doubled to 70 milliard m3 by 1985 as indicated on tabel4. This may be possible but it will take considerable incentive and capital. It is rather optimistic to assume that LNG (liquefied natural gas) from North Africa, West Africa or even the Middle East will fill the remainmg gap; the 40 milliard m3 shown for 1985 is a very

high figure again and it assumes an increase of 30 milliard m3

during the period 1975-1985. Gas will increasingly be a premium fuel, probably for household use only. Electricity for industry will not be allowed to be generated from imported LNG and as a result the conventional liquid hydrocarbons will continue to be a major source of domestic energy.

Summarizing, taking the optimistically foreseen domestic oil supply and the total gas supply (including imports), these add up to some 25 to 30% of Western Europe's energy demand by the mid 1980's. With the energy contribution of domestic coal decreasing and being replaced by increased nuclear energy, Western Europe will still depend on imported crude oil by 1985 for 50% of its energy requirements, a situation probably not worse than that of the USA by that time and definitely much better than Japan's,

THE NETHERLANDS

Although one should consider Western Europe as a political and consumption unit, a forecast is presented of the Netherlands energy picture, assuming one could look at the Netherlands in isolation.

NETHERLANDS ENERGY BALANCE

lO'80E/O 2000 NUCL£AR

iBTSro®

1500

~" 1000

."" OIL 500

0 COAL

1950 '55 '60 '65 '70 '75 '80 '85

Fig. 9 Netherlands Energy Balanc~.

Fig. 9 shows past and future energy requirements and the composition of the energy package for the Netherlands. What strikes us here is the large share taken up by gas, originating mainly from the Groningen gas field, compared to which additional reserves and expectations from the Dutch part of the continental shelf are minor.

A surprising fact about the Groningen gas field IS the recent information that the reserves are already fully committed, meaning that all of the Groningen reserves will be required to satisfy export commitments and to secure domestic supply until the end of the century. It is sometimes suggested that the Groningen field could be produced faster. This could, however, be detrimental to the gas re&ervoir as it

16 A. HOLS

could result in loss of ultimate production; in other words, it would be against the best interests of the nation and the customers. The reason for this development is that the value of Groningen gas increased faster than its price. It was like a "sale" with customers flocking in to pick up bargains.

Any additional reserves from the land area of the Netherlands are expected to be small compared to the Groningen field and will not appreciably affect the basic picture. Offshore reserves are of course in the "expectation" class, but so far results have not been too encouraging. Gas has been found and will be found, but there is no reason to believe that the total additional reserves come anywhere near to those of the Groningen field. They will contribute to the Netherlands and Western Europe gas supply but not in any Significant way.

The percentage of natural gas in the Netherlands energy balance will grow from the present 35% to 52% in 1980, it will drop to 44% by 1985, although the volume of gas consumed is expected to increase from 800,000 barrels of oil equivalent per day to close to 900,000 barrels of oil equivalent per day from 1980 to 1985.

Nuclear capacity which will still be negligible in 1980 is assumed to increase to 5% of the energy demand in 1985, equivalent to an output of 100,000 barrels of oil equivalent per day, which is consistent with the recent announcement by the Government that by 1985 ten nuclear plants are expected to produce a total of 8000 megawatt.

Although by 1985 the nuclear energy generated will be approximately lOO,OOO barrels of oil equivalent per day, it is more realistic to compare this output with the amount of oil, gas or coal saved, that otherwise would be burned in power plants. With a thermal efficiency of conventional generators of some 33%, one can say that nuclear plants will displace 300,000 barrels of oil equivalent per day by 1985, which otherwise would have to be delivered by our gas fields or imported as gas, crude or thermal coal. The 1985 gas figure being on the high side, European coal still losing ground and assuming nuclear energy to provide about 5%, the Netherlands are facing during this critical period (when worldwide proven reserves are running down) imports of some 1 million barrels of liquid fuels per day or 50% of Dutch energy requirements. Some of this crude will of course originate from Western European sources and the Netherlands' dependency on Middle Eastern crudes may be expected to be somewhat less than the Western European dependency as a whole.

FINAL REMARKS

As has been said before, liquid hydrocarbon supply plus possible imports of gas for Western Europe are not expected to be more than 25 to 30% of its energy supplies in the mid eighties. The great deficit to be filled by imports is to be met in the first place from the Middle East and North Africa. If the producing countries make the crude too expensive or

restrict supplies (as Kuwait and Libya are doing now) Europe will be forced to look elsewhere to fill this gap. As mentioned before the only alternatives are from new frontiers for conventional crudes, such as the as yet little explored areas in the Arctic, the deep sea, or from crudes from oil shales, tar sands or coal, major resources of which are not located in Europe but in the Western Hemisphere. It may be naive to continue to count on the Western World to solve our domestic problems and even if the U.S., which have large coal and shale reserves, would be willing to help, the price can be expected to be very high. High prices are already facing us from resources such as the North Sea, and in the longer term from the deep sea and increased Middle East Government take. Of course one may wonder whether demand would not be affected if energy prices were going to increase as predicted; this is a subject certainly worth looking into seriously. The basic premise on which all present major forecasts are made, i.e. the relationship between energy demand and gross national product may not be tenable in the long run.

The following are a few of the critical conclusions drawn from what has been presented so far.

Summary for penod 1980/1985

W. Europe the Netherlands

Local energy resources commItted yes yes

Crude OIl and natural gas avaIlability fully utIlIzed yes yes

Come-back of domestIc coal no no Dependent on hydrocarbons 75% 90-95% Dependent on imported) inc!.

hydrocarbons ) thermal 75% 45-50% Dependent on Imported) coal

crude oil ) imports 85% 95% Dependent on Imported gas*) 30% Dependent on Imported energy 55% 50%**)

*) From sources outside Western Europe. **) Not necessarily from sources outside Western Europe.

Further conclusions that could be drawn from the paper covering the next 15 years are the following.

Time of "easy " and cheap hydrocarbons ends around 1980. Oil continues to be vital to the prosperity of Western Europe and the Netherlands. For hydrocarbon imports we will depend on Middle Eastern, North African and Communist sources. Domestic resources of oil and gas will contribute at best one third of the hydrocarbon requirements of Western Europe. North America is less dependent on imports of fuels than Western Europe and Japan. Alternative supplies can only come from high cost resources such as from Arctic, deep sea, liquefied gas, synthethic fuels.


Western Europe should not count on North America to solve their long term energy problems. Environmental requirements may accelerate our energy problems. As "a nation that runs on oil cannot run short", Western Europe and the Netherlands, forming part of it, need a dedicated energy policy, to guarantee security of energy supply which should: a. realize that stock piling of hydrocarbons is only a short

term measure; b. identify politically doubtful regions of supply; c. stimulate developments in the nuclear field; d. stimulate exploration in Europe and new areas; e. realize that the oil industry needs to be encouraged

rather than to be pursued to reach these goals.

REFERENCES

Books

De Golyer & MacNaughton (1971) - Twentleth Century Petroleum StatistiCS.

Meadows, D. (1972) - Limits to Growth. Aula 500 (Neth. edition). U.S. National Academy of Sciences & NatIOnal Research Council

(1969) - Resources and Man. Freeman & Co., San Franslco.

Reports

Cameron Engllleers - Quarterly Report "Synthetic Fuels". Denver, Colorado.

KoninkliJk Instituut van Ingemeurs, StlChtlllg Toekomstbeeld der Techniek (1972) - Electncitelt in onze toekomstlge energJe voorzienlllg. The Hague, the Netherlands.

The NatIOnal Petroleum Council (1972) - Reports No. I-Von the "U.S. Energy Outlook", Washington, D.C.

Lecture

McLean, John G. (1972) - The U.S. energy outlook and its ImplicatIOns for Western Europe. (presentation to Amencan Chambre of Commerce, London, 13th June 1972).

Magazines

Chemisch Weekblad (1970) October. The Hague. Energy InternatIOnal (1970) August. (1972) Apnl. Forbes Magazme (1971) August 1. New York. Fortune (1971) August, October. Chicago. De Ingemeur (1965) September 17. (1971) July 23. The Hague. Journal of Petroleum Technology (1965) November. (1969) Decem-

ber. (1972) May. Dallas. New Scientist (1969) November 13. New SCientist & Science Journal (1971) August 5. Oil and Gas Journal (1969) December 29. (1971) January 18,

February 15, March 8 and December 27. (1972) May 8. Tulsa. Petrole InformatIOn (1970) June 12. Pans. Petroleum Press Service (1970) January, February, June, July. (1971)

September, October. (1972) March, June. London. Revue Fran~aise de l'Energie (1970) No. 218, February. SCientific American (9171) September. New York. Time Magazine (1970) May 25, October 19. (1972) January 24, June

12. New York. World Oil (1971) August 15. Houston.

VERHANDELINGEN KON. NED. GEOL. MIJNBOUWK. GEN. VOLUME 29, p. 19-36,1973

THE GEOLOGY OF THE CARBONIFEROUS IN THE COAL FIELD BEATRIX IN CENTRAL LIMBUFiG. THE NETHERLANDS AND IN THE ADJACENT GERMAN AREA

W.F.M. KIMPEl)

ABSTRACT

A revIew IS given of the geologIcal prospectmg of the undeveloped coal deposIts m the Beatrix area of the Dutch State Mines on the southeastern contmuation of the Peel horst.

The area has been investIgated by a drilling campaigtl, seismic reflection surveys and by the smkmg of two shafts whIch was stopped In 1962. The top of the Carbomferous is encountered at depths between 400 and 700 m. The coal-bearmg Westphalian A and the Lower Westphalian B have a jomt thIckness of about 1,450 m. In the Hendnk Beds and the Wllhelmma Beds coal seams wIth more than 50 cm coal compnse 2% of the total sectIon, m the Baarlo Beds 0.5%. These percentages correspond very well WIth those of South Limburg.

The geolOgIcal coal reserves above 1,200 m below sea level are determmed at approxImately 800 million tons, of which about 130 mIllion tons are situated on Dutch terrItory. One third IS "Esskohle" or coaking steam coal, two thirds represents semi-anthracIte and anthraCIte. The relatively hIgh degree of coalIfication mcreases both to the southwest in the directIOn of the Peelrand fault and to the southeast, pomtmg to heat supply from a deep-seated mtruslve body near Erkelenz, as suggested by Telchmuller.

Large quantItIes of brackIsh thermal salt water of ascendmg character flowed from the Westphal!an A and B strata mto both shafts.

INTRODUCTION

The concession of the originally Dutch State Mine Beatrix, taking up an area about 23 km2 , is situated in Central Limburg, some 10 km east of the town of Roermond, in the municipalities of Vlodrop and Melick-Herkenbosch at the Dutch-German frontier. It was planned to extend the exploitation of coal seams of Upper Carboniferous age also to the adjacent concession area in Germany, which covers a surface of about 107 km2 • The whole area, comprising some 130 km2 , is called "Great Beatrix". The concessions are bounded in the south by the coal field Sophia-Jacoba in Huckelhoven (Germany), in the west and north by the "Peel coal fields" (P eel com m iss i e, 1963).

\) RIJks GeologIsche DIenst, GeolOgIsch Bureau, Akerstraat 86-88, Heerlen, The Netherlands.

The coal-bearing Upper Carboniferous strata in the Beatrix coal field are covered by an overburden of 400 to 700 m thickness and locally even up to 950 m. In general it consists of Tertiary and Mesozoic sediments of Upper Cretaceous age (P eel com m iss i e, 1963; Pat ij nand Kim p e, 1961).

The activities in the Beatrix area started on the Meinweg plateau in the beginning of 1955; the deepening of two shafts down to the Carboniferous was ceased in mid-1962. Subsequently the shafts gradually filled with water and have been closed.

Geologically the area is part of the southeastern continuation of the Peel horst, situated to the northeast of the Peelrand fault. Towards the soutwest the deep and 20 to 25 km wide Roervalley graber. separates this area from the South Limburg Mining District.

The geological exploration of the Carboniferous in the area has been carried out over many years by means of drilling campaigns and geophysical investigations, both on Dutch and on German territory.

In a number of publications (P a t ij n, 1958; Pat ij nand Kimpe, 1961;Peelcommissie, 1963;Thiadens, 1963) and reports several aspects concerning the geology of the Carboniferous in the Beatrix area have been discussed seperately, but a more or less comprehensive picture as to the stratigraphy, tectonic structure, coal reserves, coalification and hydrogeology has not yet been written.

AVAILABLE DATA

In 1952 both the Dutch State Mines and the governmental Peel Committee started a modern prospecting campaign by drilling and seismic reflection surveys in the Beatrix area and in the Peel region in order to explore the possibilities of coal mining. The prospecting work was terminated in the Peel region in 1956, in the Beatrix area in 1959 (Van R i e 1, 1957,1958 and 1965; Patijn, 1958; Peelcommiss i e, 1963; T h i a den s, 1963). Shaft sinking in the Beatrix was started in 1955 by the Dutch State Mines.

The knowledge of the ~eology of the Carboniferous and

20 W.F.M. KIMPE

the overlying strata in the Beatrix area is based on information obtained from boreholes, two not completely sunk shafts, geophysical exploration and physical borehole measurements.

In order to construct the maps and geological sections as presented here, the following - rather old - information has been used:

the boreholes Briiggen I, II and Ill, Elmpt 1, 3, 4, 8 and del f s t 0 f fen" (1918), Vlodrop 3 (1907-1908), 12 (1910) and 132 (1926); the boreholes 131 and 133 (1926-1927) of the Biermans Consortium; the boreholes Briiggen I, II and II, Elmpt 1, 3, 4, 8 and 15, II, V and VI, Tamen II, Ill, IV, V, VI and XV, Dalheim 7, 8 and 9; the boreholes Dorothea 25 and XIV, situated closely south of the border of con session and all on German territory (see E r Iii ute run g e n, 1921 and 1922);2) the boreholes XLVII+a (1922) and XLVIII (1922) (T h i a den s, 1963) drilled by the Dutch State Mines; gravity measurements executed by the Dutch State Mines (1940- 1945; see E i n d v e r s I a g, 1949).

The more recent data comprise the results of seismic exploration, carried out by the Prak1a Company, Hannover, at the request of the Dutch State Mines (1952-1953), at the request of the Peel Committee (1953-1955) and afterwards once more at the request of the State Mines (1958; Van Riel, 1957, 1958 and 1965); the boreholes LXX (1953), LXXVII (1958) and LXXVIII (1954), LXXIV (1954-1955) and LXXVI (1956) drilled at the request of the Peel Committee, situated close to the Beatrix area. These boreholes have always been continuously cored in the Carboniferous. Various physical measurements have been carried out in the boreholes as well (Van Riel, 1957); finally the geological sections of the Beatrix shafts I and II which represent the most recent geological data.

In the entire Beatrix area 30 deep borehoks in total have been drilled, representing an almost entirely cored Carboniferous of about 7,000 metres, varying per borehole from 10m up to 720 m of cored section (prospecting well LXX).

The seismic reflection surveys in two parts of the Beatrix, Vlodrop-Herkenbosch (1952-1953) and Elmpt (Germany, 1958) comprise in total over 200 km seismic profiles with 765 shotpoints, divided as follows, table 1.

Taking all exploration data together we now have sufficient geological information to present a comprehesive geological view on thickness distribution, stratigraphical sequence and lithological composition of the overburden as well as the stratigraphical and structural developIl.ent and

2) Of the numerous "Fund"-boreholes, usually situated In groups close to each other, only the most Important are conSidered here.

TABLE 1

Beatnx area

Dutch part German part

seismiC shot seismic shot profiles points profiles pOints

1952-1953 43 km 137 6km 14 1958 15 km 60 141 km 554

coal-bearing character of the Coal Measures. Of great interest are the thicknesses and correlations of the individual coal seams, the fault pattern, the coal reserves, the gas content of the coal, as well as composition of the water and temperature gradient in the Carboniferous.

STRATIGRAPHY

The stratigraphy of the Carboniferous strata of Westphalian age and the correlation of coal seams between the numerous old and the three recent boreholes, LXX, LXXVII and LXXVIII in the Beatrix area are given in the Report of the Peel Committee (1963) and by T h i a den s (1963). For a succinct discussion, including the flora and fauna, the reader is referred to these publications.

A series of Westphalian strata, some 1470 m thick at the utmost, are found in the Beatrix area. A standard section is presented in figure 1, showing that only the lower part of the Westphalian has been preserved. The section comprises the complete Westphalian A and part of the Westphalian B. The Westphalian A is about 1,110 m thick. The lower Westphalian A or Baarlo Beds, measuring some 670 metres, have a considerably greater thickness here as compared with these strata found in South Limburg (K imp e, 1961). The upper Westphalian A or Wilhelmina Beds are about 440 m thick. Only some 360 m of the lower Westphalian B or Hendrik Beds have been preserved. The general depositional and environmental character of the Westphalian series in the Peel region and in the Beatrix area, the marker horizons, such as the majority of the marine bands and kaolin-coal-tonsteins (K imp e, 1967 and 1969), as well as the occurrence and development of the coal seams, correspond fairly well with those in the coal basins of South Limburg, Aachen-Erkelenz and the Lower-Rhine. Also here, the persistent kaolin-coaltonsteins found in the coal seams G.B. 3 ) 20/19, 35, 36 and 41/40 appeared to represent first order correlation horizons. The Sarnsbank marine band, the boundary horizon between Namurian and Westphalian, is only known from borehole LXXVI, north of the Beatrix area. The other marine bands in the Baarlo Beds, the Finefrau Nebenbank marine band and

3) Standard denominatIOn of the coal seams by the Geologisch Bureau.

THE GEOLOGY OF THE CARBONIFEROUS IN THE COAL FIELD BEATRIX IN CENTRAL LIMBURG, THE NETHERLANDS AND IN THE ADJACENT GERMAN AREA

21

Fig. 1

coal seam

45a III d) 45

~ z: ~ 44/43

c(o:a..J

average c.,.1 ~hlcKness

75 100 9S

::J uJ III E II) c( > :Ie g 41/401:S+--l125 :J >-.., o XO~IO ..-4. Ou c ~ ... ...J z: 37/36 O-+-~l~O .- au) a..J E EI&I J: 35 :J'tl~ := ~ Cillh8rlnil M B

b1---I120

~ ~ -------32--- 85

115 ....... E

> U ~~ 1ll,..._O L. E'- '" .r:.~-:O~ ....I..~-.::. c~ 0 I'D ';' > I 52 I ._ .... ~ E 0

c(

30/29

~ 27 a..J 25 III 24

?;c(E20 .... Z:O 19 Q. -~ Q. ~~ __ ~ 10 17 oJ a..J u

J: ~

~ 13

3

•••.•••. 75

5S 7S

--+--175 55

115

.:.:.:.:. 90

.:-:.:.: .

. :.:.:.:. 90

70

~0?-1Io0?

.:-:.:.:. 8O?

.:.;.;.:.

.........

.MrI1$NI?K M B ........................................ .. ....

Standard sectIon of the Westphalien In the Beatnx area, With the

principle coal seams, tonsteins, the most important sandstone layers

and coal classes.

the marine horizons in the Girondelle group, have also been encountered in some of the Peel boreholes. Only in one of the Peel boreholes has Lingula been found in the Wasserfall marine band. The Catharina marine band nowhere contains a marine or brackish macrofauna. The uppermost part of the Hendrik Beds seems to have been removed by erosion in the Beatrix area. Apparently the influence of the marine transgressions in the Upper Westphalian A and Westphalian B in Central Limburg has been weaker than in South Limburg. Nevertheless, reliable coal seam correlations could be established. Discussions on the comparison between these basins

have been given by Kim p e (1961) and B a c h man n, Her b stand Kim p e (1970). An overall picture of the stratigraphic correlation of the coal seams in the boreholes and shafts in the Beatrix coal field is presented in figure 2, also showing the thickness of seams with more than 50 cm of coal. They seldom reach a thickness of more than 150 cm of coal, sometimes of 100-150 cm, but usually 50-100 cm. About 15 to 20 well-developed coal seams can be traced in the majority of the boreholes in the lower Westphalian series: 4 in the Hendrik Beds, 10 in the Wilhelmina Beds and 3 in the Baarlo Beds. The percentages of coal in these beds are given in table 2.

TABLE 2

Hendrik Beds Wilhelmina Beds Baarlo Beds

coal seams with more than 50 cm of coal

2 % 2 % 0.5%

all coal seams

2.5% 3 % 1 %

These percentages correspond fairly well with those in South Limburg.

SHAFT SECTIONS

The shafts are situated at a distance of 100 m from each other in NWW-SSE direction on both sides of the prospecting well LXX.

The methods of shaft-sinking as used in the Beatrix 'mine' as well as the tickness of overburden and Carboniferous and the depth where shaft-sinking was ceased, are summarized in table 3.

The thickness of the Carboniferous in the two shafts averages 235 m, comprising the lower part of the Hendrik Beds, Lower Westphalian B and the upper part of the Wilhelmina Beds, Upper Westphalian A. The Catharina marine band which does not contain any macrofauna here, is only represented by a thin layer of bituminous shale in the roof of the coal seam G.B. 32. The succession of coal seams in both shaft sections and borehole LXX can be fairly well correlated. The stratigraRhic correlation as well as a probable tectonic interpretation of the faults are shown in fig. 3. In the shaft sections only one thick coal seam, G.B. 29, not encountered in borehole LXX, is present in the Wilhelmina Beds and has a seam thickness of 200 cm of which 150 cm is coal. The other coal seams in this sequence only have small coal thicknesses. In the lower part of the Hendrik Beds, measuring about 155 m, of which only some 130 m were visible in the shafts, two thick, pure coal seams, G.B. 35 and 37/36, occur, having an average seam thickness of 106 and 140 cm, of which 102 and 135 cm consist of coal. Each of these coal seams is characterized by a kaolin-coal-tonstein layer by which their statigraphic identification could be determined (K imp e, 1967 and 1969). The section below coal seam G.B. 35 is relatively rich in sandstones and quartzitic sandstones.

22 W.F.M. KIMPE

LXXIV LXXVIII LXXVII Shaft II LXX Shaft I 133 131 XLVII+a Vip 3 XLVIII 132 Dalh 8 Dor 25 Dor XIV Tam XV coal seam

45°

45

44/43

41/40

37/36

35 34.33

32

30.29 { 27 25° 25 24 23

158-

105-

142-

121-

100- 151-------

101 == :~ --- {lm~ 175-___ ___ 5O.,:CjFliaJ;.!'l:!_

50 ------- 156- 170 ___ _

60 --- 75 - 75 ------9Z 110-__ _

::$--61- .... "- 1115-13Z ___ _

73-' ------

116-

145-

61 - ___________ _

110_

w.I-____ _

50 -----87---- ,

L~G~ND

> 100cm coal 7O-100cm coal

~ 50- 70cm coal < 50cm coal

1 r fault

~~ J~~JE R{~- ~ 160 HllO-F ? 250-

11111 ~11O- 87 95-

[200m

[ 100m

Om

coal seam

41/40

37/36

35 34.33 ___ ~a..tI~ __ .J!o.s..n1 ~-..::.:-:... ___ Da.J.hl _______ _

32 170- 30+29

90-------65-------50 -;-""------

105 iO-

65 -=== ~ ==---- 24 --- 90 5Z ---}

~l ::..::::-:: 66 ______ 20/19

59 ----------- : ._---================ 61 ___________ _ 20/19 (

:=::-::~~= 2~; 111~ 111 75 _) 18

17 160/16 15

-----========= 66--::_-_-= ~101===== i ~-------- 17 188/16

;);~~ ;; 13 12 11

99~ 1118-------10/-__ _ :

139 I I 80-~--~:::.-.,al1 ___ '~k60 -----M • .:-,;;. _B!!"t_ ------- U -------

78---_

-g80- 10?

Dalh 9

85------- 99

110- 8/7

Fig. 2 Stratigraphic correlation of the most Important coal seams and theIr thicknesses m boreholes and shafts, Beatnx area.

The coal seams are lying rather flat, striking N-S to NNE-SSW and dipping 5_60 west. Four, mainly NNW-SSE, sometimes NE-SW striking, small normal faults, dipping 30-850 west, have been encountered in the shafts. Three of them have a throw between several decimetres and up to about 5 metres, only one has a throw of about 11 m. The amount of throw generally seems to increase with depth. A prognosis of their presumable course of intersection is indicated in the geological section. The fault with a throw of about 11 m at a depth of 700 m in shaft I may be considered as the southern terminal part of the Beatrix fault. Its occurrence as a major fault further to the north was already proved in several seismic sections in 1952-1953. Afterwards its presence was also assumed in the prospecting well LXX.

The difference in position of coal seam G.B. 28 in shaft II

TABLE 3

Overburden

Surface at +77.64 m N.A.P. Method Homgmann-De Vooys

Shaft I (drop-shaft system) 5/1955 - 7/1959) Thickness about 480 m

Surface at +77.63 m N.A.P. Method Homgmann-De Vooys

Shaft II (drop-shaft system) 8/1955 - 9/1959 Thickness about 480 m

and borehole LXX with that in shaft I might suggest the presence of an up throw fault with a throw of about 7 m.

SUBCROP MAP OF THE CARBONIFEROUS AND GEOLOGICAL SECTIONS (fig. 4)

The map of the surface of the Carboniferous (fig. 4) presents an overall picture of the currently known stratigraphic and tectonic relationships of the Carboniferous (compare also Patijn and Kimpe, 1961). Four cross sections (fig.S) and four longitudinal sections (fig. 6) have been constructed across a number of boreholes for further elucidation.

Depth and trend of top Carboniferous, unconformably covered by the Aachen sands and clays (Campanian) and

Carbomferous Total Depth

Top at -402.87 m N.A.P. Ordmary shaft-smkmg

8/1960 - 8/1962 Thickness about 238.5 m 717.38m

Top at -402.77 m N.A.P. Ordmary shaft-smkmg

3/1960 - 8/1962 Thickness about 232.5 m 711.35 m

FIg. 3


North South Shaff II Borehole LXX Shaff I

NAP. coal seam 0 v E. R BUR 0 E. N coal seam -;'00 m- -<QI.Slmlf.A.P. .02,57 If.AP.

r~H~~:,,,!~g~;;; .:.:,~::..!!, .... · ....... ··~, ',::"""" '" ............ '<:'-C' :;'. 'ii~': ;,'\ . 1 ..... 1 - - - - - - - - - T .:. {lOes 50se

38? ! ,:' -~- 10se- - -- - - - - .! W. ~'':' ... ::: ... .8 jt" 1

? 38

I ~ .-:.. ! .,. i

W'I",i",WOh '200~~II' ,P ),1: \_:::. ~; ~ 160

.,:;:. 626gc·cpyr. 21 T 37/36 ... . 65 ""I {60 _-------.

"1 '~1' 6.pyr· 2T _______ ' _ 56.<\ -"50m- 37/36 ~ _ 70 7 ,..cr· "1' :::.: .. :.1 ~ ... 200 ......... I/m ..

- Bee ~I'~,~ ~. _~ 12.0 I/m. . .;.:.. 1 J .. /

6 ! I~: .....

·1 :;:;: A .'.-.

o.ol/m. 'i 16)1. • ! ",,',

3000 I/m. ;j .. !i' I

-500 m- 35:Q.:

""

.... I

1;'5cC I37 ____ - -- - -'r 128«

{~;. --------~j ~·;:;'."'·,;,.z· ;:;'.z·l1·z·,,·;;:.·1:'·z·1:' .. ",."'··. { 11_ - - - - - - - - _ _ f

72sc------- --'3' . ~ r:r~ 28 f "li~:fB~E:I~·IC::i·:r:!::1 ...

-5S0m-

-GOO m -

- 650m-

32

31 30

370 I/m.

155c

1;5 _--------- 't' ----,il 2Ocs----- , 1

2~f 28

120 3 ,; ...... <]· I~ 8cs "'-'.~ I, ,!

,.- 13 ~ .~ .-' 16se J,I,I....1,1 t r~t~ 19cs 10 __ -;."'~:'7i 21cC'- SC<;so:D GlP t 'H Mm.

,.00 Ifm.

".::.p .. :.:-... --------~ 27 d.p~h 7ff,3Sm - -

Situati on

oeorthol. LU

os ... n I

Hm '-~ ........ ~-!

..

I I

;' I t'

000 I/m.

he 3it+33 7 }

25 fObH.

~"0vm .

• 2000 I/m . JO'.,

117cc t 7cs

32

1000 I/m.

31

30

29

28

, 1 '~{~~sc3~ 27 24 31S l/<n.

3 'r-I ? 26 ~~~ .. '

25

GeologIcal sectIon of the Carbomferous ill the Beatnx shafts I and II and borehole LXX.

23

206 210

24

202 206 210

Fig. 4 Contourmap of the top Carboniferous, Beatrix area.

212

LE.GE.ND

HtHDRIK BEDS

Ct7I1!t7rillt7 M 8

WllH£LM IHA BEDS

Wasserl'al/ AI 8

8AARlO BEDS

Samsbal7k M 8 E15 Borehole E1S,depth oHop o~.9S Carbon iferous marked in

merers below sea-lmI.H.A -------- Contw;rsoftop -- -S()(J-- Carboniferous -~- Subcroppofcoalseam5 -r - Normal fault

-t- - Rever,e fault >----.... , line of geological sediOli --0-- Boundary of coalfield ................... fronher

212


25

sw

sw SECTION II

I'll , NE. .. ,: SECTION III

O v erburden

• • 00

v.m.

o

FIg. 5

~ ri

E1S

NE.

NE. ml'l " P

.00

LE.GE.ND Coa l clas5t5

., FeHkonl" ': mQ:dium volatile coking or - baum inous coal

.. E.$$kohle': coking stQam or low volatile bitum inous coal

.. Magerkollle': dry s~eam or s2mi - an~hraci h:

2km

GeologIcal cross sections (SW-NE), wIth the coal classes accordlllg to the volatile matter content of the coal seams.

younger deposits, have been derived from boreholes, shafts and the seismic reflection survey. The Carboniferous surface is at its highest in the southern part of the area (- 350 m N.A.P.).4) To the north and east the depth gradually increases to - 450 and - 600 m N.A.P. West of the Zandberg fault the Carboniferous is lying deepest, about - 650 m N.A.P.

In the northeastern part of the field the surface of the Carboniferous is an about 200 NE dipping, fairly flat abrasion platform. In the southwestern part the Carboniferous surface

4) Below sea level.

shows a rather irregular picture. This may be attributed to young tectonic movements along a number of faults, of which the Zandberg and the Beatrix faults are the most important. As a result of these tectonic activities the direction and amount of dip, up to gO, on the different fault blocks vary appreciably. Throws up to some 300 m at the surface of the Carboniferous, as seen along the Zandberg fault, have been proved.

A local deviation of the general dip of the Carboniferous surface, as seen as a WSW-ENE trending slope, coincides with an overthrust west of the shafts in a fault block between Meinweg and Zandberg fault (fig. 4). It apparently represents a rather exceptional structural element in the Carboniferous

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202 206 208 210 212 214 27 ~r-__________ ~~~05~' __ ~ __________________ r-_______________ ._ ••• ,-__________ ~6~1~0~' __ --r------------------,-------------------,368

NETHERLANDS o 2km

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FIg. 7 Contour map of coal seam G.B. 13, Merl, lower Wilhelmllla Beds (Upper Westphaltan A).

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202 210

FIg. 8 A. Contour map of coal seam G.B. 27, Groot Langenberg, upper W!lhelmma Beds (Upper Westphal1an A), B: Contour map of coal seam G.B. 41/40, Hendrik Beds (Lower Westphalian B).

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Honzontal section through the Carbomferous, - 600 m N.A.P. level.

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Cafhartna M. B. WILHELM INA S£.DS

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Fig 11

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Total coal thicknesses (111 metres) of coal seams thicker than 50 em above the -950 m N.A.P. level up to the top Carbomferous.

31

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202 206 208 210 212 2110

Fig. 12 A: Total coal thicknesses (in metres) of coal seams thicker than 50 cm between the - 1200 and - 950 m N.A.P. level; B. Area of total coal thicknesses of 5 to 15 metres above the - 1200 m N.A.P. level.


33

of thIS area. Both faults and overthrust are claer!y seen in section V of fig. 6 between the boreholes LXXVII and XLVII+a. The presence of the WSW-ENE striking and southward dipping overthrust could be ascertained from seismic profiles.

As a result of the general west dip of the Coal Measures the Baar!o and Wilhelmina Beds (Westphalian A) and the Hendrik Beds (lower Westphalian B) are subcropping in stratigraphical order form east to west. The eastern limits 0.f the coal-bearing Upper Carboniferous, as may be seen in fig. 4, are supposed to be lying within the eastern boundary lines. In the northeastern part they are formed by the Sarnsbank marine band; in the eastern and southeastern part by a major fault.

The mainly NNW-SSE trending beds are intersected by a number of N-S to usually NW-SE striking longItudinal normal faults, which for the greater part dip to the west, such as the Zandberg and Beatrix fault. They may be considered as synthetic mmor faults of the Peelrand fault. The oblong fault blocks deepen gradually towards the Roervalley graben. As shown on sections I-IV in fig. 5 the faults dip in the same direction as the beds, but opposite to that of the Carboniferous surface.

There are strong mdicatIons that a major NNW-SSE trendmg fault IS present near the eastern limits of the coal field. Its probable pOSItIOn and roughly estimated trcnd is shown m fig. 4. An indication of the presence of this fault is derived from the occurrence of some faults m the northeastern part of the coal field Sophia-Jakoba in Huckelhoven (Germany), as was shown by the 1952 seismic exploratIOn campaIgn. It IS furthermore supposed that thIS fault continues along the eastern boundary Ime of the Beatrix field but In any way east of the boreholes Dalhcim 9, Tamen IV and Elmpt 3 and then bends in a northwestern direction. This fault might correspond with one of the faults lying between the Second East Peel fault and the north-south trending Boundary fault immedIately east of the Dutch-German frontier, west of the boreholes Vorst and Wachtendonk in which wells the presence of the Namurian and DinantIan respectIvely has been proved. Probably one has to deal with the fault near borehole 14, west of the Second Peel fault (T h i a den s, 1963, encl. 1,2and4).

CONTOUR MAPS AND HORIZONTAL SECTlONS

Further mformation on thc position and form, the extent and tectOl11C picture of the coal seams IS provided by the contour maps of three of the most Important coal seams, G.B. 13 or Mer! (fig. 7) and G.B. 27 or Groot Langenberg (fig. 8A) in the Wilhelmina Beds (Upper Westphalian A) and G.B. 40/41 (fig. 8B) in the Hendrik Beds (Lower WestphalIan B).

The contour lines of the gently, almost monociElally

5_100 westward dipping coal seams G.B. 13 and 27 have a strike of about NNW-SSE in the north and central part of the coal field changing to approximately N-S 111 the south. In the western part, near the German frontier, a flat synclinal depression is developed of which the NNW-SSE axis is lying near the boreholes LXXIV and LXXVII.

The sub cropping, mainly SE-NW trending coal seams, dip to the west and are cut off in the west by the Peelrand fault and ItS eastwards trending subSidiary faults. The coal seams are cut up in different fault blocks by a number of likewise SE-NW trending strike faults gradually going down to the Roervalley graben. These stepfaults are the Zandberg fault with a throw of about 300 m, the Beatnx fault With 100 m throw and the Klem Gladbach fault haVing a throw of about 50 m. A WSW-ENE trending and southward dipping overthrust of pOSSIble Variscan age forming a later partly revived structural element could be traced west of the shafts.

Two maps have been constructed as honzontal sections through the Coal Measures, one at the level of -600 and another at -950 m N.A.P. (fig. 9 and 10). It clearly appears that the level of -600 m N.A.P. IS mtersected by thc WIlhelmina and IIendnk Beds, In a NW-SE trending, on an average 3 km wide zone m the central part of the Beatrix area between the Zandberg fault and the Wasserfall manne band. These beds conta1l1 the maJonty of the coal seams and consequently the largest quantity of coal.

At the -950 m N.A.P. level (fig. 10) the coal-nch zone of the 1l1tersected Wilhelmina and Hendnk Beds IS sItuated further west. It must be noted, however, that below this level the Hendnk Beds are practically lack1l1g, whereas the Wilhelm1l1a Beds at both sides of the Zandberg fault average about 2 km In width.

A general Idea of the coal thickness of the seams and their horizontal distributIOn according to borehole data is gJVen In fig. 2.

The core recovery of the coal seams 111 recent boreholcs was practically 100(ic. The amount of coal 111 tons net t per square metre (NT/m2 ) has been calculated USIng the cores of the seams 111 the boreholes LXXVil and LXXVIlI according to the method of a complete coal seam InvestIgation, as discussed by B e u gel s, B 1 0 erne n d a I and Kim p e (1960). Thc amounts of coal in the pnncipal seams (compare fig. 1 and 2) in these boreholes are presented I!1 table 4.

The average coal thickness of the seams With more than 50 cm of coal amounts to about 90 cm I!1 the Baarlo Beds, 80 cm in the Wilhelmma Beds and 120 cm in the Hendnk Beds. A few coal seams may reach a coal thIckness of 150-200 cm, exceptIOnally 250 cm. It can be assumed that about four coal seams In the WiIhelmma Beds and two m the Hendrik Beds have coal thicknesses of more than 70 cm over the entire Beatnx area or the larger part of it.

The average distance betwecn the prmClpal coal seams Il1

the different senes of beds is vanable. In the Baarlo Beds, having a conSiderable thickness of some 670 m WIth only a few coal seams, this distance is averaging about 150 m. In the

34 W.F.M. KIMPE

TABLE 4

coal seam Nr. G.B.

45a 45 44/43 41/40 37/36 35 32 29 27 25a 24 20 19 17 13

coal in tons nett per m2 (NT/m2)

borehole LXXVII

1.1 1.1 1.2 1.4 1.9

1.7 0.9 1.9 1.1 2.1

borehole LXXVIII

1.4 1.8 2.1 2.5

1.6 1.0

1.1 1.0 1.8 1.6

Wilhelmina Beds, with many coal seams, this distance is short, averaging about 25 m, varying between 15 and 80 m. In the Hendrik Beds the average distance is 60 m, varying between 20 and 100 m.

COALIFICATION AND COAL CLASSES

A number of aspects concerning the coalification in the Peel region and in the Beatrix coal field and the factors which might have played a role in it have been discussed by K u y 1 and Pat ij n (1961).

Volatile matter, as determined from the specially preserved coal cores (K irk e Is and K u y 1, 1960) of Westphalian A and lower Westphalian B age of the Beatrix coal field is less than 20%, pointing to a fairly high to high degree of coalification (fig. 1). For further information on percentages of volatile matter of coal seams in the various boreholes the reader is referred to the stratigraphic borehole sections in the report of the Pee 1 com m iss i e (1963) and T h i a den s (1963).

The content of volatile matter varies from approximately 22 to 5%. The majority of the available coal is semi-anthracite (10-14'10 v.m.) and anthracite (less than 10% v.m.), whereas low volatile bituminous or cokmg steam coal (14-20%) represents the minority. Medium volatile bituminous or coking coal (20-22% v.m.) is almost entirely lacking. The distribution, position and extent of the different coal classes according to theu content of volatile matter IS indicated m the geological sections of fig. 5 and 6. It should be noted that the surfaces of equal volatile matter age lying flatter than the coal seams themselves and consequently intersect them at very small angles. Some displacement of these surfaces across a few of the major faults, such as the Meinweg fault, can be assumed.

As usual the degree of carbonization of the Upper Car-

boniferous strata increases with depth. Consequently the percentage of volatile matter decreases by 1 % per 60 m increase in depth. A distinct lateral variation in the degree of coalification can be seen in each individual coal seam notably a general increase from northeast to southwest, i~ other words towards the Peelrand fault (K u y 1 and Pat ij n, 1961). The volatile matter content decreases in this direction with an average of about 8% (fig. 5). A general, in fact lesser increase in the coalification seems to manifest itself from northwest to southwest, which may be seen as a small decrease in the volatile matter content and is especially noticeable in the longitudinal sedtions VII and VIII (fig. 6). These phenomena are in complete accordance with the general picture of coalification and the trend of the isovoles in the adjacent area of Erkelenz in Germany, where anthracite occurs in the coal mine Sophia-Jacoba at Hilckelhoven (H e r b s t, M. & R. T e i c h mull e rand S tad 1 e r 1971; H a h n e, 1972). The cause of this local coalificatio~ maximum is ascribed to heat supply by a deep-seated, large intrusive body of lac co lithic shape near Erkelenz, east of the Peelrand fault (M. & R. T e i c h mull e r, 1971).

COAL RESERVES

Based on the currently available data the geological coal reserves have been assessed for the whole Beatrix coal field on Dutch and German territory, taking all coal seams with more than 50 cm of coal into account. For practical purposes and in order to get figures comparable with the coal reserves as calculated in the Peel region (P eel com m iss i e, 1963), the amount of the reserves is calculated, taking the total volume of coal in the coal seams over 50 cm thick down to a level of -1,200 m N .A.P. This volume has been multiplied by the average specific gravity of the coal to obtain the amount of coal in tons. The lateral changes in coal thickness have been derived from borehole results.

The geological coal reserves have been assessed at two levels, one at -950 m N.A.P., the other at -1,200 m N.A.P. For this purpose two coal thickness maps have been made (fig. 11 and 12). On each of these maps the distribution of the totalized thicknesses is indicated for areas with differences in coal thickness of 2 metres of the superincumbent coal seams with more than 50 cm of coal. Fig. 11 presents the totalized coal thicknesses on the level -950 m N.A.P. and figure 12A on the level -1 ,200 m N .A.P. The geological coal reserves thus assessed (table 5) amount to:

TABLE 5

above the -950 m N.A.P. level above the -1200 m N.A.P. level

total

mllhons of m3

about 480 about 160

about 640

mllhons of tons (average s.g. 1.3)

about 620 about 210

about 830


35

Some 130 million tons of these total estimated coal reserves are present in the concession on Dutch territory, About one third of the total coal reserves is "Esskohle" or low volatile bituminous or coking steam coal, two thirds belongs to the class of "Magerkohle" or semi-anthracite or dry steam coal and anthracite.

The maps indicate that I) by far the largest reserves are lying above the -950 m N.A.P. level, 2) seams of an integrated thickness of 10-12 metres occur only in the southern part of the coalfield, 3) a coal thickness of 6-10 metres occurs over a large area and seams of 6-8 metres integrated thickness only in a small area above the -1200 m N.A.P. level in the western part of the concession.

Summarizing, it may be stated that above the -1,200 m N.A.P. level an integrated coal thickness of 5-15 metres occurs only in the western half part of the Beatrix concession (fig. 12B).

HYDROGEOLOGY

During the construction of the Beatrix shafts I and II it was discovered that the traversed rock series of the Westphalian A were strongly water-bearing. Large quantities of water, often as water outbursts, poured into the shafts at many places.

To determine the location and character of the waterbearing layers or fault zones, it was decided to regularly drill vertically downwards from the bottom of the shaft. To prevent the influx of water into the shafts the surrounding rock was impregnated under high pressure with a cement slurry.

Despite considerable precautions a few water bursts occurred in both shafts. The location and quantity of the greatest water inrushes have been indicated on the section of fig. 3. It is obvious that almost all water inrushes originated

mNAP

-400_ water sample 10 shaft [

tl;!-Ce-HCO, warer. water sample In shaft II x

-450-

ti;!-~-HCO, wafers

brackish wat-er~ -500-

!::!;!-~-[Hco,l warer'

-550 -

saIl- warers Na-Ce warers ~ w,rhCa/~

-600-

~ . -650-

350 300 250 200

FIg. 13

in very sandy formations (hydro stratigraphic stability, Kim p e, 1963) and in fault zones. The occurrence of strongly developed joint systems in the sandstones causes not only considerable macroporosities, but especially large macropermeabilities.

The highest pressure of the water amounted to 50 atmospheres, as measured in boreholes at a depth of about 600 metres and about 130 metres below the top of the Carboniferous. The water pressure as measured at various depths in the shafts appeared always to be higher than would correspond to the hydrostatic pressure in relation to the top of Carboniferous. This might be due to the fact that the deposits of the Aachenian, overlying the Carboniferous, are very sandy. As a consequence, this formation is permeable in contrast to the Aachen clays which are overlying the Carboniferous in the northern part of the Beatrix coal field (P eel com m iss i e, 1963).

The temperature of the water varies from 22°C at a depth of 530 m up to 31°C at 700 m. This appears to be higher than the rock temperature of 27.2°C, as measured at a depth of 747,70 m in the Carboniferous in borehole LXXVII 3 km to the west. In relation to the local Carboniferous geothermal gradient of 22.3 m, as determined from various reliable temperature measurements in this borehole (P eel com m i s -s i e, 1963; T h i a den s, 1963), this turns out to be about 6°C higher. This observation might indicate that ascending thermal salt waters occur along a fault. Well-known examples of ascending thermal, strongly mineralized salt waters have been reported from the Carboniferous in the South Limburg mining district (K imp e, 1963).

HYDROCHEMISTRY

The chemical composition and the hydrochemical development of the waters in the overburden and in the Carboniferous in the Peel region and in the Beatrix area have been discussed previously (K imp e, 1963).

150

SECTION OF depth SHAFT I .nd II In m

sample coal-no seam

/'op C"rl>omf"<'rQVS <"8 -40Jm /fl .. _·Jl·····1; : ~

.I; ~ 1 32 6

22 36 26 37 42

500

37/Y,

.-------Na+~1 c~(

J.

/ ./ , \1 ,

550

\ ! HCO' (+CO"): Iso"

3 3 : I •

hardness ,...,..-'I. German degrees'/ \

..-- , //

, , / ,

JS

600 40 ..... 50 •••••

5 2 49

5 1

.. CathMB

650

/ , ~ n 700

/ \ / 66

100 50 0 -+----- m eq It

Hydrochemical diagram of waters in the CarbOniferous III the Beatnx shafts I and II.

36 W.F.M. KIMPE

In the Beatrix area chemical analyses of Carboniferous water samples are only available from the shafts. A number of these analyses, of which the concentrations of the main cations (Na + K and Ca + Mg, given as total hardness in German degrees) and anions (CI, S04 and HC0 3 + C0 3 ) are expressed in milliequivalent per litre of water, is represented graphically in fig. 13. The total amount of dissolved solids of about 2,000 mg/I and the conductivity of about 3,000 microhm at top Carboniferous at a depth of about 480 m, are increased tenfold at about 720 m. It appears that the water in the Carboniferous has a high degree of mineralization increasing quickly with depth. Thus the chloride content at the top Carboniferous at 480 m depth amounts to about 20 m eq./I (about 700 p.p.m.). Apparently really fresh water is absent in the Carboniferous. Some 250 m deeper the chloride content has increased to nearly 350 m eq./l (more than 12,000 p.p.m.). Consequently only brackish and salt water appears to be present in the Carboniferous. The transition is lying near a depth of about 630 m. On average the chloride content increased by about 130 m eq./l (about 4,600 p.p.m.) per 100 m depth lllcrease.

The content of alkahes increases less quickly than that of chloride, whereas the concentration of earth-alkalies increases as well, so that at about 640 m depth there are likewise some earth-alkali chlorides dissolved in the water. Consequently the total hardness increases considerably (up to about 75 German degrees). The content of bicarbonate decreases continuously, whereas the sulfate content is reduced to zero. We can therefore distinguish a change in concentration of the different ions, leading to a vertical zonal distribution of hydro chemically different types of water (figure 13; Kim p e, 1963).

The regular increase of the cloride and alkali content shows a distinct interruption caused by a relatively too low content of these ions at a depth of 610-620 m (sample nos. 40 and 50, fig. 13). The cause of this gap is not clear, nor is it clear whether it is a local or a more regional phenomenon. It has been observed that this divergence is found in a sequence of the Carboniferous whIch IS nch in sandstone and quartzite layers. It seems possible that a relatively greater permeability of this sequence has caused a deeper penetration of some less salty water into the Carboniferous due to a strong withdrawal of the water in the shafts.

ACKNOWLEDGEMENT

The author wishes to express his sincere thanks to Ir. A. Hellemans, member of the Managing Board, D.S.M., Heerlen, for his kind permission to publish this paper.

REFERENCES

Bachmann, M., G. Herbst and \V.F.M. Knnpc (1'170) - DerzeilIgcr Stand der FlozparallellSlerung zWIschen den Stemkohlcn-

revlCrcn der NJederlande, von Aachen-Erkelenz und vom NJederrhelllgeblet. C.R. 6me Congres Intern. Strat. Geol. Carb., ShefflCld 196 7, p. 445-452.

Beugels, P.A.G., J. Bloemendal and \V.F.M. Klmpe (1960) - Nleuwe methode voor structuurmetmgen van steenkoollagen en voor de berekenmg van de hoeveelhcld verkoopbaar product per oppervlaktc-eenheld. Geol. en MIJnb., 39, p. 213-226.

De geophYSISche dlcnst der StaatsmlJnen (1949) - Emdverslag van het geophyslsclie onderzoek 111 ZO-Nederland. Meded. Gcol. StICht., Ser. C-I-3-1, 372 pp.

Hahne, C. (1972) - Neue gcologlsehe Forsehungen 111 den NordwesteuropaJschen Stcmkohlen-GeblCten. Das Ste111kohlengebiet von Aachen-Limburg und Erkelenz-Peel. Zbl. Geol. Palaont., I, H. 1/2, p. 26-42.

Herbst, G., M. & R. Telchmuller and G. Stadler (1971) - Das RevJer von Aaehen-Erkc1enz. Fortschr. Geol. Rhe111ld. Westf., 19. p.61-73.

Klmpe, W.F.M. (1961) - Strahgraflsclie ontwlkkelmg en correlatlC van de koollagen van de Baarlo groep, Onder Westfahen A, 111 ZUld-Limburg met een vergehJkmg tot die m de omliggendc

geblCden. Geol. en Mljnb., 40, p. 265-290. (1963) - GeochemJe des eaux dans Ie HOUiller du Limbourg (Pays-Bas). Verh. K.N.G.M.G., Geol. Serie, 21-2. Jub. Conv., p. 25-45.

-- (1967) - Occurrence, development and distributIOn of Upper Carbomferous Tonste111s In the parahc West German and Dutch coalflClds and thcu use as stratigraphiC marker honzons. Meded. Geol. Sheh!., N.S. 18, p. 31-38.

-- (1969) - ReparhtlOn et caracteres petrograpluques des Tonsteins dans Ie Westphahen A + B du baSSin hOUiller du Llmbourg (Pays-Bas). Ann. Soc. Geol. Nord., LXXXIX, p. 249-260.

Kukels, P.A.H. and O.S. Kuyl (1960) - Verfahren zum Schutz von Kohlenkernen fur petrographische und physlkahseh-ehcmlsche Untersuchungen. Gluckauf 96, p. 43-44.

Krause, P.G. and E. Zimmermann (1921) - Erlaut. zm Geol Karte usw., Lief. 195, BI. Burgwaldmel.

Kuyl, O.S. and R.J.H. PallJn (1958) - CoalificatIOn In relatIOn to depth of bunal and geothermiC gradient. C.R. 4 me Congres Strat. et G601. du Carb., Heerlen 1958, p. 357-365

PatlJn, R.J.H. (1958) - Geological survey of a coalfield m middle and northern Llmt·urg. C.R. 4me Congres Strat et Geo1. du Carb., Heerlen 1958, p. 513-520.

PatlJn, R.J.H. and W.F.M. Klmpe (1961 - De kaart van het Carboonoppervlak, de proflClen en de kaart van het dekterrcm van het ZUld-Llmburgs MlJngeblCd en StaatsmlJn Beatnx met omgeving. Meded. Geol. Sllcht., Ser. C-I-I-4, 12 pp.

Peelcommlssle Rapport van de (1963) - Deel II, Elndverslag van de Geologlsch-MIJnbouwkundlge subcommlssle Staatsdrukk. en Ultg., p. 47-85.

van RJeI, W.J. (1957) - Emge aspecten van de explora:1C van het PeelgebJed. Gcol. en Mljnb., N.S., 1ge Jrg., p. 53-61.

__ (1958) - The exploratIOn of a Dutch coal baSin, a hlstoncal review. Geoph. Surveys In mlnmg, hydro1. and engm. projects European Ass. Expl. Geoph., The Hague, p. 138-156.

__ (1965) - Synthetic seismograms applied to the seismic Invesllgalion of a coal baSin Geophys. Prosp., XIII, p. 105-121.

Thladens, A.A. (1963) -- The PalaeozOiC of the Netherlands. Verh. K.N.G.M.G., Geo1. Sene, 21-1, Jub. Conv., p. 9-28.

Van Waterschoot van der Gracht, W.A.J.M. (1918) - Emdverslag van RIJksopsponng van Delfstoffen m Nederland 1903-1916.

Wunstorf, W. (1921 and 1922) - Erlaut. zur Geol. Karte usw., Lief. 195, B1. Bu:gelen; B1. Wegberg, BI. Elmp!.

VERHANDELINGEN KON. NED. GEOL MIJNBOUWK. GEN. VOLUME 29. p. 37-42, 1973

SALT

PRESENT AND FUTURE USE AND PRODUCTION 1)

I.A.A. KETELAAR 2 )

ABSTRACT

The use of salt m the Netherlands, the Common Market and the USA IS discussed. About 70 percent of total productIOn is used for mdustrial purposes, mamly m the chemical industry. The development of the productIOn of salt IS shown to be closely related to that of the chemical mdustry.

The methods of winning are discussed m relatIOn to use.

SAMENV A TTING

Het gebrUlk van zout in Nederland, EEG en de V.S. wordt behandeld. Ongeveer 70% van de gehele produktie wordt gebrUlkt voor mdustnele doelemden, voornamehJk in de chemische mdustrie.

Aangetoond wordt dat de ontwlkkehng van de produktie van zout nauw verbonden IS aan die van de chemlsche mdustrie. De wiJze van wmnmg wordt besproken met betrekkmg tot het gebrUlk.

Salt has been produced, sold and used in many places on earth already in prehistoric times. With only few exceptions all peoples knew and know salt, ordinary salt, as an essential ingredient in food, both directly and indirectly for the conservation of fish, meat and vegetables.

The yearly consumption of salt in the developed countries is 6-8 kg per capita, but there are large areas on earth where this is only 3 kg per capita. The consumption has a tendency to decrease slowly as salted meat, vegetables and fish, with the exception of herring, hardly figure on the daily menu nowadays.

The use of salt in the kitchen has diminished with the decrease in the consumption of (boiled) potatoes.

The use of salt for human consumption in the Netherlands amounted in 1970 to 90,000 metric tons, which is about 7.4

1) Lecture before the Kon. Ned. Geol. Mijnb. Genootschap m the Hague on March 18, 1972.

2) Akzo N.V., Arnhem, The Netherlands

3) 1 (metnc) ton or 1 tonne IS 1000 kg.

percent of the total use of solid salt of 1.223 million m. tons. 3 ) In other countries this percentage is about the same: USA 5.5 percent, West-Germany: 5.2 percent (lit. 1,2,3,4).

Besides its function as a food ingredient, salt also plays a role in the maintainance of public health as small quantitites of iodine are added to most consumption salt. In Switzerland the desirable addition of fluorine to the human diet is obtained by adding trace amounts of fluoride to consumption salt.

The large scale use of salt for deicing and snow removal on roads is rather recent. However, it is the most rapidly growing single application both in the USA and in WestEurope.

In the Netherlands the use of deicing salt or road salt increased from 45,000 tons in 1962 to 130,000 tons in 1965 and to 400,000 tons in 1969 and 390,000 tons in 1970 or about 30 kg per capita. The average percentage growth was 25 percent for the period 1965-1970. In the Netherlands in 1969 and 1970 1/3 of the total use of solid salt or 14 percent of the total production was used for deicing and snow removel on roads (lit. 3,4). However, in 1971 and also thus far in 1972 little road salt has been used because of the mild winter.

In the USA in 1970 35 kg per capita or 40.3 percent of total consumption of solid salt was used for this purpose against 31 percent in 1964.

The use of salt for snow removal is limited in general to the region of the earth between latitude 40° and 60° N. Further north and also at lower latitudes, but at great altitudes, such as in the Alps, snow removal with salt is not very well possible because of too much and too frequent snow falls and or very low temperatures.

In the foregoing years the use of road salt has increased much more rapidly than the number of cars or than the length of roads. The general public and the road maintainance authorities apparently put in higher demands for safety and reliability than they did formerly. The use of large quantities of salt on roads has its drawbacks. On one hand damage to roadside plantations is possible, though only rarely manifest, because of the dormant state of plants in

38 I. A.A. KETELAAR

winter time. On the other hand salt, though never the cause, is a factor that accelerates the corrosion of cars. Addition of inhibitors increases the cost considerably whereas the actual effect is small or even insignificant.

There are in practice no other expedients than salt. In very special cases only, other remedies are considered

such as urea etc. on runways of airports or electric heating of the road surface on approaches to tunnels and bridges.

By far the largest part of the salt production is used for industrial purposes, mainly in the chemical industry.

In olden times the technical use of salt, except for the conservation of food and hides, was restricted to the glazing of coarse earthenware such as stone jars (Cologne pots) and sewer pipes and also to salt out soap from the saponification of oil and fats with lye.

The first use of salt as a basic chemical took place in 1823 in England in the first chemical industry, the production of sodium sulphate from sodium chloride and sulphuric acid.

Sodium sulphate was again the primary material for the Leblanc soda process. The hydrochloric acid fumes liberated in the first mentioned process, also formed the first case of severe air pollution. However, also the English Government took efficacious control measures and the alkali act was the first law against industrial pollution.

Nowadays salt is the basic material for the production of chlorine and sodium hydroxide or caustic by electrolysis of a solution of salt in water. Together with quick lime, salt is also the primary material for the production of sodium carbonate or soda ash by the Solvay process, which has completely superseeded the Leblanc process long ago. There are numerous other small scale applications of salt in the chemical industry and in a number of other industries.

Of the total production of salt, as both solid salt and as brine, about 70 percent is destined for industrial use in the Netherlands, the Common Market and the USA (lit. 2, 3, 4).

For the electrolytic production of chlorine-caustic this percentage of total salt production is 38.5 percent for the Netherlands, 33 percent for the Common Market and even 46.5 percent for the USA. The production of soda ash takes up 22, 26 and 14 percent respectively. Together these two large chemical processes take up 60.5 percent in the Netherlands, 59 percent in the Common Market and 60.5 percent in the USA, or about everywhere 60 percent, of the total salt production (fig. 1 and 2).

It is thus only to be expected that the development of the salt production is directly cou~led to that of the chlorine production or more generally to the development of the alkali industry.

A comparison of the growth percentages in the period 1965-1970 shows that the growth of the salt production is about 0.7 times that of the chlorine production. For the Netherlands, the Common Market and the USA these growth percentages are for salt production lOA, 7.75 and 5.8 percent respectively and for the chlorine production: 14.1, 10.7 and 9.2 percent respectively.

Now the chlorine production is an accurate gauge for the

EXPORT

57,'" 1,6,5 "tonn ••

CONSUMPl'ION

42 I 51' 1,22 "tODD ••

SOLID SALT

PRODUCTION

2,87 Mtonnea SOLID

£.a.l! "tonne_ BRINE

,,21

FIg.!.

NETHERLANDS

1970

SALT 9,'" MISCELLANEOUS

5 % CQMSUHPl'ION t BUMAIt

25 ~ ROADS

22 ~ SODA ASH

,8,5~ CHLORINE - CAUSTIC

CONSUMPTION

1,56 Htonne.

ConsumptlOn pattern of salt 111 the Netherlands 111 1970.

V.S .. A..

MISC.

MISC. CHili.

PAPER,

PULP .-

CHLOS:.

HYDRO_

CARBONS

Cl2 8,86

lISA

7 "ISC.

. , NIIM'NC.

17 ROADS

14 SODA ASH

46,~

CHLORltlE

- CAUSTIC

u.S.,' •

COIDai HARKa'

MIlt. PROD.

2~ ... MISC.

II OL~EROL

OLICOL

MISC •

l' HYDRO-CARBOIIS

VINYL. 26

CHLORIDE

TRI I PER 2~

CHLOR.BIORCC.

.... 22 ..... .... .... .... ...

........

--------

" " " "

5 8

6

26

"

CHEMIC.

OD

6, MISC.

7 SOAP OIL

1.5 TEXTILE

9,5 ALUMINIUM

-COMMON MARKET

WISC •

HUHAII CONS.

ROADS

CHEM. ~D INO

SODA ASH

CHLORINE-CAUSTIC

COMtlOH HARKl;'!' 2, .18 HtC)nn ..

20,.8 Minh. 1970 18""4 Minh.

FIg. 2

22" Mlac.

12., NA-PB08P1UU

6" DE'rERG.

7 Hft'ALLURG.

51.5 GLASS

ConsumptlOn patterns of salt (NaCl), chlonne (CI2), caustic (NaOH) and soda ash (Na2C03) 111 the Common Market and the USA 111 1970.

SALT, PRESENT AND FUTURE USE AND PRODUCTION 39

TABLE 1 Cumulative Growth Percentage 1965-1970

USA Common Market

Netherlands E.E.G.

Salt 5.8 7.75 10.5 Chlorine 9.2 10.7 14.1 Sulfuric 3.2 4.0 7.7 Index of

chern. prod. (c.P.) 7.0 12.0 9.1

development of chemical industry as a whole. A much better gauge than the sulphuric acid production figures, which were formerly used as a yardstick of the activity of the chemical industry (fig. 3 and 4 and table 1).

The future development of the use and thus also of the production and the mining of salt will be closely dependent on the development of the chemical industry. It has hardly been more difficult than today to make a long term prediction with any degree of certainty.

The production of salt in the Netherlands has grown

400 r-----------------------------------~ I 400

CI2 I I 380

I I 360 I

340

320

300 350

280

I 260 I

I 240 I

I 220 , I

200 , 200 I

I I : /.-I

..... '". 180

168

140 "':'H SO ." 2 4

/ 120 " ,..--100 +---------------~~----------------_+100

80 , H25q.'.~.-. ,

I 60 I ,

CPo ,

40 ,,-"CI

20 EEG

o 0 1947 49 51 53 55 57 59 61 63 65 67 69 71

1958 Fig. 3 Index of productIOn of chlorine (Cl2), sulphunc aCid (H2 S04) and index of chemical productivity (C.P.) for the Common Market (ht. 1, 6).

rapidly from its beginning in 1919 in Boekelo, later in Hengelo (0) 'and Delfzijl (fig. 5). Extrapolation of the Netherlands salt production towards the year 2000 (fig. 6), assuming a cumulative growth percentage of 10.4 percent as in the period 1965-1970 would result in a figure of 62.5 millions tons, twenty times the present-day total production in 1970 of 3.21 million tons. With a yearly growth of 6 percent, as found for the period 1968-1970, a production would result in 2000 of 18.s million tons or about six times the 1970 rate. (fig. 6).

1969

CI 2

200

180

160

140

120

100

80

60

o 1947 49 51 53 55 57 59 61 63 65 67 69 71

1958

Fig. 4

280

260

240

220

200

180

160

140

120

100

Index of chlonne, sulphunc acid and mdex of chemical productivity (C.P.) for the USA (ht. 1,7). _

106 tonnes 100010nnes

300

200

100

8 .H -8 '0 a 19~2~O----~19T-3~O------1~94~O------~19C50~----~19~6~O------1~97~O 0

Fig. 5 ProductIOn of salt m the Netherlands (ht. I, 4) + H. start Hengelo plant, - B c10smg of Boekelo plant, + D: start of Delfzljl plant.

40 J.A.A. KETELAAR

100 6 10 tannes

10

3.21 Mt

·S +0

62.S Mt /0 /"

/" /

1960-1970 = 104 % // ....0

/' / ___ -- 1aS Mt

0.1 L_-r-_-r-_-r-_-r-_-r-_-r-_~_.:.,ye_a_r--'r---, 19S0 1960 1970 1980 1990 2000

Fig. 6 Projected productIOn of salt III the Netherlands - B: c1o~lIlg of Boekelo plant, + D start of DelfzlJI plant

In recent years changes have taken place in the use of chlorine caused by the development of new processes for which less chlorine is used. With the Introduction of one atom of chlorine in an orgamc molecule also one molecule of HCI is formed in many cases. According to the oxychlorination process with the simultaneous addition to the organic vapour of chlorine and air (or oxygen) and the use of a copper chloride catalyst the HCl formed is immediately oxidIzed to chlorine and water.

Oxychlorinahon thus results in the use of half the quantity of chlorine as was formerly used, e.g. for the production of vinylchloride. Also, it will already become economically feasible in some cases to convert hydrochloric acid, formerly a nearly valueless, often embarraSSIng, waste product, into chlorine by electrolysis or by the Shell chlorine process.

Nevertheless the capacity of the chlorine production in the Common Market of the six will increase in 1971 and 1972 by 1 mIllion tons (lit. 8), that is a quantity equal to 25 percent of the 1970 production (and 1 millIon tons of CI2

takes 1.75 million tons of salt). The present position of the chemical industry charac

terized by declining profits and rentability and a reticent investment policy IS dictated by both conjunctural and structural factors. With respect to the latter, it seems doubtful if the older, high growth percentages of 10 to 12 percent will soon if ever come back. On the other hand a large and growing output of the chemical industry is a condition for the increase and for the maintenance of a high level of prosperity, but it is also a condition for the welfare of world population as, e.g. the war on all types of pollution including its own will be fought to a large extent with the means of the chemical industry.

From the system analysis of the world by For res t e r and Mea dow s (1972) the most important conclusion, as the best objectively quantified one, is the exhaustion of natural resources, both inorganic (metals) and organic

(bitumina). The plastics which can replace to a large extent metals are nowadays manufactured on the basis of oil and natural gas as primary materials, but the scientific possibility exists, though the economic feasibility can be seen only in the distant future, to use coal and even the unexhaustible resources of carbonate in the calcareous sediments as the source of carbon and with hydrogen from water as the ultimate sources with the help of fusion and solar energy via the production of acetylene, C2 Hl as intermediate.

The stocks of salt both in the oceans and on land are of such a gigantic size, also in the Netherlands that exhaustion, or even scarcity will never become a problem for salt.

Salt is won in three ways: as sea salt by solar evaporation, as mine or rock salt from underground mining and as brine by underground dissolution in solution mining.

For industrial use, for the production of soda ash and for diaphragm electrolysis for chlorine and caustic production, in most cases the cheap, saturated brine is used as such, without prior evaporation. In the USA in 1970 57.2 percent of total salt production was in the form of brine as against 30.8 percent rock salt and 8.5 percent evaporated salt and 3.5 percent sea or solar salt (lit. 2). In the Common Market about half the production is rock salt, against 10.5 percent sea salt, against in the Netherlands no rock salt at all and only 12 percent as brine and thus 88 percent as evaporated or vacuum salt (lit. 3, 4). In Europe, contrary to the USA, the large majority of electrolysis plants are equipped with mercury cells, which need as feed solid and very pure salt, contrary to diaphragm electrolysis cells. It is to be expected that also in Europe a relative shift in favour of brine away from both rock salt and evaporated salt will take place. It seems doubtful if ever new rock salt mines will be opened, although exploitation of existing mines will be continued.

Soluti9n mining demands much less labour and is far better adaptable to deep lying deposits, so that this method will certainly find still wider application.

The possibility nowadays exists for transportation of salt by pIpe line as brine or as a salt slurry in brine in stead of transport of solid salt by rail or by ship.

In Canada solution mining is used since 1964 also for the winning of potash. Solution mining with solutions of special compositions and recycling, opens possibilities for selective extractions, as otherwise only possible with (underground) mining and ore separation methods. Because salt is a very cheap product the cost of transportation soon becomes an essential part of the cost price at the place of consumption. Thus the sales of sea salt will be limited to a restricted area, irrespective of the rather low price for a product that otherwise has a much lower purity than vacuum salt, which is chemically pure sodium chloride.

Finally there is also what could be called a negative use of salt. With this is meant the preparation of empty spaces in salt deposits, other than in salt mines, to obtain underground storage room. On several places on earth such storage rooms have been obtaIned by solution mining of salt where the brine produced has been mostly drained away. Besides the

SAL T, PRESENT AND FUTURE USE AND PRODUCTION 41

USA, e.g. in France a complex near Manosque has a total size of 1 million m3 and Gaz de France has in use four storage rooms of 100,000 m3 each. In West-Germany there are five cavities of 900,000 m3 in total in use by Shell and Mobil. In all these cases the cavities serve as storage room for liquid fuels, especially for liquified gases under pressure.

The possibility is beeing investigated to use such cavities for the storage of dangerous wastes especially of liquids or slurries. However, it is not so simple to displace the brine as in the case of liquid fuels, without the mixing to a certain degree of the aqueous solution or of the slurry with the brine, already under the influence of the geothermal gradient in the cavity.

Genetically and chemically potassium and magnesium salts are closely related to rock salt.

In the Netherlands, in Friesland (Sexbierum) and in Groningen (Uithuizermedenr deposits to the extent of 300 million tons, have been found at a depth of about 2000 m.

The exploitation of these deposits both for potash and for the production of magnesium metal by molten salt electrolysis has not yet been undertaken.

It is not easy to find a profitable market for an additional 30,000 tons and later 60,000 tons of magnesium metal, when the total world production has not yet reached 200,000 tons. In the future however, magnesium will playa bigger role

when the reserves of good quality bauxite are nearing depletion.

For the moment however, there is rather an overproduction of aluminium metal. The future remains a closed book although we know the contents and many words from the register; however, the text can only be guessed.

LITERATURE

1. R. cox, The production of salt in the Netherlands, Verh. K.N.G.M.G., 21(1963) p. 97. 1.A.A. Ketelaar, Het zout der aardc. chapter X, Kon. Ned. Zoutlndustne, Hcngelo (0), 1968.

2. Minerals Yearbook, 1969, Bureau of Mines, Washington D.C. 1971, Mineral Facts and Problems, U.S. Bureau of Mmes, Bull 650, 1970 Ed., Washington D.C., 1970.

3. MaandstatlstJek van de bUltenlandse handel, Centraal Bureau voor de Statlstlek, 22(1971), NT. 12.

4. Salt World survey of productIOn and consumptJon with speCial reference to future demand and pnces. RoskIll InformatIOn Services, London, 1971.

5. Chemeurop, CEE, Serdlc, Pans. 6. The chemical mdustry, l'mdustrie chimique, 1969/1970, OCDE,

OECD. Pans 1971, and earlier cd. 7. Chemical Economics Handbook, Stanford Research InstItute,

Menlo Park (CaL). 8. Europ. Chem. News, Chemscope, New Plants, 25.2.1972, p. 72.

VERHANDELINGEN KON. NED. GEOL. MUNBOUWK. GEN. VOLUME 29, p. 43-50, 1973

THE MIDDLE TRIASSIC LIMESTONE (MUSCHELKALK) IN THE ACHTERHOEK (E. GELDER LAND)

H.M. HARSVELDT1)

ABSTRACT

ThIS artIcle summanzes the results of a detailed geological survey carried out in and near the quarries of the N.V. Winterswijkse Steenen Kalkgroeve, where Triassic limestone has been excavated since 1935.

FIeldwork carried out to the east of the existing quarries to investigate a possible extension of the explOItation m that direction, indicated a reserve of about 6.4 x 106 tons of limestone.

SAMENVATTING

Het artIkel behandelt de uitkomsten van een detail onderzoek, uitgevoerd m de groeven van de N.V. Wmterswijkse Steengroeven waar kalksteen van Trias ouderdom smds 1935 wordt ontgonnen.

Veld werk Ultgevoerd ten oosten van de bestaande groeven met als doel een eventuele verdere ontgmnmg in oostehjke richting van de kalksteen te onderzoeken, toonde aan dat m het gebied tussen de bestaande groeven en de Nederlands-Duitse grens nog een voorraad van 6.4 x 106 ton kalksteen aanwezig IS.

In many boreholes in the eastern part of the Netherlands the Muschelkalk has been found. Exploitation of this limestone in quarries is only possible east of Winterswijk, where the Muschelkalk subcrops close to the surface and can be economically exploited. The maximum thickness here amounts to almost 30 m.

The formation in this area shows a maximum dip of about

NNW

200m

FIg. 1 GeologIcal profIle of the Muschelkalk m the Wmterswljks area.

1) Rljks GeologJsche DIenst, Spaarne 17, Haarlem. The Netherlands.

10° to the NNW (fig. 1). The limestone section thins in a southerly direction, making way for the older part of the Triassic, the Upper Bunter.

In a northerly direction the formation disappears underneath Liassic strata. The exploitation by open-cast mining becomes impossible as soon as the overburden is more than five metres. (see figure 1)

Regarding the earlier exploration we refer to my publication in the Transactions of the Jubilee Convention, part two.

One of the major applications of the limestone is in agriculture. The magnesium content of a number of layers in the limestone, marl, and shale sequence in this part of the Muschelkalk is such that a magnesia-rich artificial fertilizer can be made. All investigations have centred around the surveying of these dolomitic limestone layers in this section.

It was found that in total six of these dolomitic limestone layers occur, indicated from top to bottom with the roman figs. I-VI.

In table 1 and 2 the most important chemical data of these layers are given. The analyses have been made on hand specimens from the quarries and core samples from borings drilled during a survey to extend the quarries.

Marker beds used in mapping are a thin grey-green limestone layer of about 5 em thickness, containing traces of galenite, sphalerite and some pyrite and a greenish grey limy shale containing remains of Lamellibrachiata. These two horizons have proved to be reliable key beds. The first layer

AREA OF QUARRIES ~

SSE

44 RM. HARSVELDT

TABLE 1: Tnasslc limestone analyses smce 1953

CaO HgO CaG!») MgC03 tot. Carbo z.1:l.b. ~)

Lir:~-::,tcno I - Quarry - 27.52 % 19.33 % 49.54 % 40.59 % 90.13 % 54.58 % Lime3tone II - Quarry - 28.07 % 19.64 % 50.53 % 41.24 % 91.77 % 55.57 %

Lioc::;tonc III - Quarry - 26.80 % 17.57 % 48.24 % 36.90 % 85.14 % 51.40 %

liz::c,"'tone IV - Quarry - 21.00 % 14.20 % 37.80 % 29.82 % 67.62 % 1+0.88 %

Linle~. tone V - Quarry - 24.40 % 13.60 % 43.92 % 28.56 % 72.48 % 43.44 ~~

? Lim~:::,':o!'e VI - Quarry - 33.80 % 5.00 % 60.84 % 10.50 ~6 71.34 % 40.80 %

LiI!lCf' tone I Quarry 2 - 27.84 % 19.81 % 50.11 % 41.60 % 91.71 % 55.57 %

Lil:C'~ ~onc II Quarry 2 - 30.51 % 19.43 % 54.92 % 40.80 % 95.72 % 57.71 % l.in:C'~: C .,;~e III 'l.uarry 2 - 26.00 % 16.56 % 46.80 % 34.78 % 81.58 % 49.18 %

Limc:~tone IV - Quarry 2 - 25.70 % 16.40 % 46.26 % 34.44 % 80.70 % 48.66 %

I·inc it',."'na V - Quarry 2 - 28.10 % 15.20 % 50.58 % 31.92 % 82.50 % 49.38 %

? Lm,';, '{ one VI Quarry 2 38.00 % 4.30 % 68.40 % 9.03 % 77.43 % 44.02 %

Lj...r.lo: :one I Quarry 3 - 27. 40 % 15.41 % 49.32 % 32.36 % 81.68 % 48.97 % LiTa(".;t·tons II Quarry 3 - 28.04 % 15.45 % 50.47 % 32.45 % 82.92 % 49.67 ~~

Linc,~cne III Quarry 3 - 26.60 % 16.34 % 47.88 % 34.31 % 82.19 % 49.48 %

*) aCid bmdll1g components

occurs about 175 cm above the top of the dolomitic Limestone 1II; the second layer lies about 160-275 cm above the top of the ore-containing horizon.

Fig. 2 shows an ideal stratigraphic section of the sequence found in the quarries. In this figure all key horizons are shown. The N.V. Winterswijkse Steen- en Kalkgroeve subdivides this columnar section into three parts as follows:

A. Calcareous marl, situated between the "ore" horizon and the dolomitic limestone 1.

B. Clayey marl, situated between the basis of the dolomitic limestone IV and the basis of the "ore" horizon.

C. Wellenkalk, situated between the basis of the dolomitic Limestone IV and the top of the Upper Bunter.

This subdivision is related to the quarrying and usage of the raw material which will be dealt with later.

The Wellenkalk s.s. consists of a finely laminated calcareous marl to clayey marl with undulated stratification. Its total thickness amounts to about 11 metres.

Two dolomitic limestone layers occur in the Wellenkalk (layers V and VI), the thickness of which is about 40 cm each.

The Wellenkalk, normally green-grey coloured, rapidly changes into chocolate brown over an interval of about

30 cm. This change of colour appears at approximately 180 cm below the dolomitic limestone layer V. Formerly this phenomenon was erroneously held for the beginning of the Upper Bunter. We have found that this was not the case. Right below the discoloration again grey green calcareous marl occurs in which again a dolomitic limestone (VI) is observed before the redbrown Upper Bunter is reached.

The clayey marl consists of a series of marly shales, marls and thin clay-layers. At the base the dolomitic limestones III and IV occur s<;,parated from each other by a marly shale layer of about 30 cm thickness. The average thickness of dolomitic limestone IV is 60 cm of dolomitic limestone III 85 cm.

The calcareous marl consists of limestones and marls. In the upper part of this section two dolomitic limestones are present (dolomitic limestones I and II). The two dolomitic hmestones are separated from each other by a layer of calcareous marl.

The limestone section described above is at present exploited in three quarries, east of Winterswijk (fig. 3).

The oldest quarry (quarry 1) situated in the west is almost exhausted. The second quarry is in operation and a third quarry in between the two has been opened lately.

As due to the dip of the layers towards the NNW an

THE MIDDLE TRIASSIC LIMESTONE (MUSCHELKALK) IN THE ACHTERHOEK (E.GELDERLAND) 45

TABLE 2: Exploration bonngs

Boring B 1, x = + 96.888, -r = - 20.075 CaO MgO CaC03 MgC°3 tot. Carbo z.b.b. Il) -Limestone II - 27.,1 " 16.13 " 49.16 % 33.87 % 83.03 % 49.89 %

Limestone III - 25.61 " 15.05 " 46.10 " 31.61 " 77.71 " 46.68 %

Limestone IV - 25.83 " 15.52 " 46.49 % 32.59 % 79.08 " 47.56 %

Limos tone V - 26.71 " 15.34 " 48.08 % 32.21 " 80.29 " 48.19 "

Limestone VI - 27.27 % 1! •• 64 % 49.09 % 30.74 % 79.83 " 47.77 "

BorinG B 2, x = + 96.505, if = - 20.042 -Li'l/estone II

Li!nestone III - 24.97 " 15.90 % 44.95 % 33.39 " 78.34 % 47.23 %

Lime:-,tone IV - 25.23 % 16.62 % 45.41 % 34.90 % 80.31 % 48".50 %

Limestone V ~ 29.27 % 15.57 % 52.69 % 32.70 % 85.39 % 51.07 %

Li!ne:otone VI - 33.22 " 13.25 % 59.80 % 27.83 " 87.63 % <;1.77 ct

Boring B 3, x = + 97.688, if .. - 20.251 -Limestone I 26.51 % 16.10 % 47.72 % 33.81 % 81.53 % 49.05 %

Limeetone II 28.91 % 17.11 % 52.04 % 35.93 % 87.97 % 52.86 )~

Limestone III 23.31 % 14.49 % 41.96 % 30.43 % 72.39 % 43.60 %

Limestone IV 27.47 % 16.46 % 49.45 % 34.57 % 84.02 % 50.51 %

Limectone V 28.21 % 15.13 % 50.78 % 31.77 " 82.55 % 49.39 %

LiIrestone VI 32.80 % 13.10 " 59.04 % 27.51 % 86.55 % 51.14?6

*) aCid binding components

Boring B 4, x = + 97.130, -r = - 20.125 - CaO MgO CaC03 MgC03 tot. Carbo z. b.b.X:)

Limestone II - 25.27 % 15.<:!4 % 45.49 % 32.00 % 77.49 % 46.61 ;6

Lime::ltone III - 26.29 % 16.39 % 47.32 " 34.42 " 81.74 % 49.24 %

Limestone IV - 35.98 % 11.49 " 64.76 % 24.13 % 88.89 % 52.07 %

LimC'stone V - 26.75 % 15.85 % 48.15 % 33.29 % 81.44 % 48.94 %

Limestone VI - 25.29 % 15.03 % 45.52 % 31.56 % 77.08 % 46.33 %

Boring 13 5, x = + 97.475, " = - 20.242 Limectone II - 26.59 % 15.91 % 47.86 % 33.41 " 81.27 % 48.86 %

Limestone III - 23.23.% 13.38 % 41.81 % 28.10 % 69.91 % 41.96 %

Limentone IV - 23.95 % 14.62 % 43.11 % 30.70 % 73.81 % 44.-42 %

Limestone V - 28.51 % 15.12 % 51.32 % 31.75 % 83.07 % 49.68 %

Limer:tone VI - 24.87 % 15.03 % 44.77 % 31.56 % 76.33 % 45.91 %

Borins B 6, x = +252.858, if = - 20.322

Limc,;tone I

Limestone II - 22.59 % 14.63 % 40.66 % 30.72 % 71.38 % 4:;.07 %

Lime"tone III - 26.97 % 15.98 % 47.55 % 33.56 % 81.11 % 49.34 %

Lime.stone IV - 27.09 " 16.10 % 48.76 % 33.81 % 82.57 % 49.63 %

*) aCid binding components

46

FIg. 2

Ui:l!A DCLA ...

~I.IH[IfOM[

Q tALCAIIlQUI MAItL

GCLAY('t' "AlII.

~ DOLOMITIC LIMelTONI

c:J .... NOy ClAVSHALI

C8:I NO UCOYUY

101. DOLOMITIC LIMESTONE

SubdivIsion of the Muschelkalk sectlOn at WmterswIJk.

H.M. HARSVELDT

extension of the quarries in a northern or southern direction is impossible, further expansion has been sought in an eastern and western direction. Extension to the west proved to be impossible. A reconnaissance boring (boring XIV) located 1 km to the west of quarry 1 hit the top of the Muschelkalk at 41 meters below surface. Geophysical evidence for a fault running in between this boring and quarry 1 has also been found.

In order to explore the possibilities of an extension in an easterly direction some fieldwork was done on the scarce outcrops, together with some shallow probes. As a result of this work, six deeper borings were drilled between quarry 2 and the Dutch-German frontier (boring BI-B6).

The borings were located on the northern edge of the Muschelkalk strip with the objective to get a completely developed Muschelkalk section. The best sections were found in the borings B3 and B6.

In the boring B3 the Muschelkalk was found 8 meters below groundlevel. The dolomitic limestone I was encountered at 11 meters depth. The boring was continued to a total depth of 42 meters in the Upper Bunter, the top whereof was reached at 41 meters.

All the dolomitic limestone layers were found. Also boring B6 was situated in a favourable position.

The dolomitic limestone I, partial eroded, was found at about 7 meters below surface.

The boring was discontinued at 31.50 m depth because sufficient information was obtained; the dolomitic limestone layers I-IV were found (see fig. 4).

The presence of faults in this part of the Muschelkalk between the Willinkhoeve and the Netherlands/German frontier is confirmed by results of a geoelectrical survey, performed at the same time. In the course of this investigation 171 Geohm and 8 terrameter measurements were carried out. In this survey the Wenner configuration was used. Advantage was taken of measurements performed earlier by the T.N.O. Faults have also been found in the sections penetrated by the borings B5, B3 and B6.

In the boring B2 the interval between the dolomitic limestone II and the "ore" bearing horizon is only 6.95 min stead of normally 13.50 m. Moreover the fossil horizon is not present. These phenomena can only be explained by assuming a fault (fault A).

In boring B 1 the distance between the dolomitic limestone II and the "ore" bearing layer is 9.25 m, what again points to a fault running through the boring (fault B).

In boring B5 the interval between dolomitic limestone V and VI is less than normal. (3.15 m in stead of 3.65 m).

A third fault has been assumed to explain this difference. Taking this geological evidence for faults into consideration the three faults found by the geophysical investigation are not surprising. This applies to the faults D, E and F, situated between boring B5 and the Netherlands/German frontier.

This means that the Muschelkalk strip between boring XIV and the Netherlands/German frontier is intersected by at least seven faults, having a strike in a NW-SE direction; the


VOSSENVElO

.. '" . . Fig. 3

4' ......

... ~ 4' . ' .' .. . .

Tectonic map of the Muschelkalk regIOn east of Winterswijk, (profile 4 mdlcated) with bonngs executed.

N,W, w

.. .. - ...

) ...

Fig. 4 W-E geologIc profIle over the bonngs.

displacements along the faultplanes are at least 2 and not more than 7 meters (see fig. 4). The western part of this Muschelkalk area, from boring XIV to the Willinkfarm, is evidently less disturbed than the part between the Willinkfarm and the frontier.

In quarry 1 and quarry 3 some minor displacements of the layers have been noted, but they are uninportant in comparison with the others.

The strong disturbance of the eastern part resulted in a miniature horst and graben structure.

Boring B3 is situated in a favourable structural position, with good development of aIle dolomitic limestones. (Though the overburden here is 8 meters one has to bear in mind that this boring has been put north of the Muschelkalk strip. More to the south, the thickness of the overburden comes back to normal - 2 meters.) The data from the shallow borings in this area were used to construct an isochore map of the overburden. The thickness of the overburden does nowhere exceed 5 meters, what means that payable exploitation of the Muschelkalk is possible.

For better evaluation, especially with regard to the correlation of the dolomitic and other limestone layers and

w.z. E

"

markers, electrical resistance measurements were carried out in the boreholes. For reference purpose the resistance log of boring B3, showing the most complete section, was used (fig. 5).

Correlation of the various layers gave no difficulties. Distinctly visible, in the SN as well as in the SL curve, is the contrast between a very rich limestone section directly above the "ore" horizon, cha~acterized by low resistance, and a much less developed limestone section in the lower part of the log.

The dolomitic limestone layers in this upper calcareous marl zone are easily distinguishable from the normal limestone layers by their smaller resistance (dolomitic limestones I and II). In the lower zone, below the "ore" horizon (clayey marl zone and Wellenkalk zone) the four dolomitic limestones appear to have a larger increase in resistance than the surrounding rocks. Also striking is the increase in resistance from the dolomitic limestones III to VI with depth.

To what extent this behavior can be explained by a higher or lower percentage of MgO in the dolomitic limestones concerned can not be determined with the scanty analyses of only a few coresamples.

48 H.M. HARSVELDT

'j

;~~ ~

... ~ -,-.

'*~ -n v:~ •

.. -;~ ::,

~,

... ~

FIg 5

I _.,. _,...J

Schlumbergcr resIstivIty log of bonng B3.

FUTURE POSSIBILITIES

Although the Muschelkalk sequence in the area east of quarry 2 has been faulted it appears advisable to carry out further explOitation in this part of the area.

In the Muschelkalk stnp between the Willmkfarm and fault D the situatIOn IS less favourable than east of fault D.

In the area around the faults A, Band C the limestone was uplIfted and the upper part of the calcareous marl (the part above the dolomitic lImestone II) was removed by erosIOn. Locally, dIrect east of fault A even the dolomitic limestone II has been eroded. Beyond fault D, up to the frontier the lImestone section subsided and a fully developed limestone sectIOn is found, the calcareous marl reaching a thickness of 18 meters and more, that is to say more than measured in quarry 1.

The overburden m the area between fault D and the frontier has a thickness of 1 to 3 meters; between the Willmkfarm and fault D a maXImum overburden of 5 meters is measured.

Due to faults the excavation of the limestone is becoming more dIfficult. Although the geological circumstances and modern explOItatIOn techniques favour a further opening of thIS area, It may be expected that in this case limitations will be imposed due to environmental considerations, closing certam parts of the area for further exploitation. This would mean that about 6.4 x 106 ton limestone cannot be quarned; the activities of the N.V. W111terswijkse Steen- en

Kalkgroeve could come to a rather early end. It is desirable that an arrangement is made between the further exploitatIOn of the quarry and the conservation of the environment.

APPLICATIONS OF THE MUSCHELKALK

A. Artifical fertilizers

From the calcareous marl situated between the "ore" layer and the dolomitic limestone I, the "Winterswijkse dolomiet", containing 4% MgO is prepared. From the clayey marl, found between the base of the dolomitic limestone IV and the "ore", the so-called "Kleimergel", containing 10';10 MgO is made.

For acid soils, having a deficiency in lime and magnesium one uses with preference "Winterswijkse dolomiet" containing about 75% CaC0 3 ; It is produced as a very fine grained

mixture (0.25 mm screen). The product holds less than 12% moisture. Is the deficiency 111 lime moderate and the lack of magnesium serious, the "Winterswijkse kleidolomiet" is used.

B. Road-building

The Winterswljkse Steengroeve delivers three products for roadbuildmg accordmg to standards set by the Ministry of Public Works (Rijkswaterstaat): a weak fIller with a bitumencontent of 40%, prepared from the calcareous marl, a weak filler WIth a bltumencontent of 45(;10, prepared from the upper part of the Wellenkalk (above dolomitic limestone V), and a medIUm filler also prepared from the Wellenkalk, but mixed with blast furnace slag, WIth a bitumencontent of 56-59(7c,.

The products are tested on tensIle strenght. For weak fillers this lIes between 20-23% of weight of the mIXture, for medIUm fillers at 24-27%. The sensitivity for water, i.e. the possibility that water displaces the bitumen in the filter, and the corresponding swell as a consequence thereof, is also tested.

Other applicatIOns

Limestone lumps as a consolidation of dikeslopes under a cover of asphalt concrete.

Medicinal use agamst grass-tetanus of cattle.

ACKNOWLEDGEMENTS

Tius article IS the result of work done m the Department of Mineral Resources of the State Geological Survey at Haarlem. The author IS much indebted to Mr. P. van Toor for his valuable help, both in the office and in the field. He also


wishes to thank the Management of the N.V. Winterswijkse Steen- en Kalkgroeve for their permission to publish the results of our studies carried out in their quarries.

REFERENCES

Geologische Stlchting (1944) - Rapport inzake opsporing en inventansatIe van oppervlakte delfstoffen m Nederland. - Med. Geol. Sticht., N.S., no. 1.

Faber, F.J. (1945) - De m de Nederlandsche Muschelkalk voorkomende grondstoffen en haar gebrUlk. - De Ingenieur, no. 11, Mijnb.2.

Harsveldt, H.M. (1953) - De hgging van de Ultradolomletmergel m de Winterswijkse Steengroeven - Dlenstrapport no. 128

__ (1954) - Proefbonngen in de Winterswijkse Steengroeven, ten behoeve van een kalksteelllnventansatIe. - DIenstrapport no. 145. ten behoeve van een kalksteelllnventarisatle. - Dienstrapport no. 145. (1960) - Controle van de hggmg van de dagzoom van de UltradolomIet m het gebled tussen de Oude en de Nleuwe Steengroeve, m verband met de aanvrage van een llIeuwe vergunning tot ontgraving, DJenstrapport no. 301. (1963) - Older conceptIOns and present VIeW regardmg the MesozOIc of the Achterhoek, WIth special mentIOn of the

TnaSSlc hmestones. - Verh. K.N.G.M.G. - Geol. Sene, deel 21-2-1963 (TransactIOns of the JubIlee Convention, part two). (1962) - Nota betreffende een kalksteen mventarisatie in de Winterswljkse Steengroeven en tussenhggende gebieden, Dienstrapport no. 381.

Harsveldt, H.M. & P. van Toor (1969) - GeologIsch onderzoek naar het verloop van de Muschelkalk dagzoom tussen de Willmkhoeve en de DUltse grens, Dlenstrapport no. 776.

Kerrebijn, D.J.L.C. (1966) - Poging tot correia tie van groeve 3 (sleuf) met de groeven 1 (oude groeve) en 2 (nieuwe groeve), Dienstrapport. (1967) - GeologIsch onderzoek van het verloop van de Muschelkalk (Ultra V) dagzoom ten oosten van de Wmterswljkse Steengroeven, Dlenstrapport no. 648. (1968) - Rapport betreffende een voorgenomen oostehjke U1tbreiding van de N.V. Winterswijkse Steen- en Kalkgroeve, Dlenstrapport no. 648A.

Overzee, B. (1968) - Geo-electnsch onderzoek WinterswiJk, afdehng Ondlepe Geofysica, Dienstrapport no. 9.

Pannekoek, A.J. et al. (1956) - GeologIcal hIstory of the Netherlands, The Hague, 1956.

Toor, O. van (1970) - Rapport betreffende een kalksteen mventansatJe m het gebied tussen de Willmkhoeve en de Duitse grens, Dlenstrapport no. 746. (1971) - InventarisatIe van de kalkmergel voorkomende onder de terremen tussen groeve 1 (oude groeve) en groeve 3 (sleuf) en ten zulden van groeve 2 (Illeuwe groeve), Dienstrapport no. 1001.


KALKSTENEN VAN HET BOVENKRIJT IN ZUID-LiMBURG EN HUN EXPLOITATIE

W.M. FELDER!)

ABSTRACT

A lithologIcal and stratigraphical descnption IS gIven of the Upper Cretaceous lImestones of Southern LImburg viz. the Gulpen limestone, the Kunrade lIm stone and the Maastncht limestone. These limestones have been exploited for construction, fertilizmg and industnal purposes for many centuries already since the flint mdustry of RIjckhole-St. Geertruid of Paleolithic tImes. Nowadays the cement industry IS the mam consumer of these lImestones. For constructIon purposes however It has served ItS term.

ExplOItable lImestones WIth a CaC03 content of 80-90% occur above waterlevel in an area S of Margraten to a maXImum of 400 million tons. North and west of Margraten some 250 million tons of exploitable pure lImestone are estimated to be available with a CaC03 content of more than 92%. Moreover a reserve of some 350 millIon tons is present of limestones lower quality.

SAMENV ATTING

Een groot gedeelte van de afzettmgen mt het Boven-Krijt, welke m Zmd-LImburg aan of dIcht onder de oppervlakte voorkomen, bestaan mt meer of minder zmvere kalkstenen. In het no orden en oosten wordt het voorkomen van deze kalkstenen, aan of nabIj de oppervlakte, begrensd door een aantaI breuken (zie fIg. 1, 2 en 3). Naar het westen dmken deze kalkstenen weg onder een dik pakket Jongere sedImenten. Naar het zuiden wordt de kalksteen begrensd door de tertIalfe en deels nog jongere eroSIebaSIS, zodat in het zmdoosten van Zuid-Llmburg reeds oudere forma ties aan de oppervlakte voorkomen.

STRATIGRAFISCHE INDELING

Reeds in de eerste helft van de 1ge eeuw bestond een levendige discussie over de stratigrafie van het Boven-Krijt in Zuid-Limburg. Staring is dan ook in 1860, als het eerste deel van zijn "Bodem van Nederland" verschijnt, in staat een vrij nauwkeurige beschrijving te geven van de verschillende afzettingen.

Na Staring zijn het vooral U hie n b roe k (1912) en

1) RIJks GeologIsche DIenst, GeologIsch Bureau, Akerstraat 86-88, Heerlen, The Netherlands

H 0 f k e r (1966) geweest die de belangrijkste bijdragen geleverd hebben tot het oplossen van de problem en rond de locale stratigrafie. Geen der onderzoekers is er echter in geslaagd een algemeen aanvaarde stratigrafie op te bouwen tussen de in het westelijk deel van Zuid-Limburg voorkomende Maastrichtse kalksteen en de in het oostelijk deel voorkomende Kunrader Kalksteen, tabel 1.

GULPENSE KALKSTEEN

U hie n b roe k (1912) verdeeide het "Gulpensche Krijt" in vijf Iithologische eenheden, Cr3a, Cr3b, Cdy, Cr3c en Cr4, tabel 2.

H 0 f k e r (1966) heeft op basis van zijn foraminiferen onderzoek een zonering opgesteld die zes eenheden omvat, A tot en met F, (tabel 2).

Een lithologische beschrijving van de verschillende door H 0 f k e r (1966) onderscheiden zones voIgt hieronder.

Zone A bestaat uit een maximaal 30 m dikke laag fijnkorrelige witte kalksteen met aan de basis 1 a 3 m glauconietrijke groen-grijze kalksteen. Het voorkomen van deze kalksteen is op Nederlands gebied beperkt tot het uiterste zuiden en zuid-westen van Zuid-Limburg. Het kaIkgehalte van deze kalksteen is niet nauwkeurig bekend. Analysen geven een· variabele samenstelling. Mogelijk ligt het gemiddeid CaC0 3 gehalte rond 80%. In deze kalksteen komen pIaatseIijk enkele donkere vuurstenen voor.

Zone B be staat uit een maximaal 10m dikke laag fijnkorrelige giauconiet-, kwartszand- en kleihoudende lichtgrijze kalksteen. Aan de basis komt 0.50 tot 1 m glauconietrijke kalksteen voor.

Het voorkomen van deze kalksteen is beperkt tot een gebied gelegen tussen Guipen, Epen en Slenaken.

Het kalkgehalte is variabel en ligt tussen ca. 60 en 80% CaC0 3 . In deze kalksteen komen geen duidelijke vuurstenen voor maar weI SiOz concentraties in vage knollen.

Zone C, die plaatseIijk een dikte bereikt van meer dan 70 m, bestaat overwegend uit een fijnkorrelige glauconiet-, kwartszand- en kleihoudende licllt grijze kalksteen. Aan de

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KALKSTENEN VAN HET BOVENKRIJT IN ZUID-LIMBURG EN HUN EXPLOITATIE 53

TABEL 2

Uhlenbroek (1912)

Cr4

Cr3c

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Cr3b

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Hofker (1966)

F

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basis en verspreid door het hele pakket kunnen glauconietrijke Iagen voorkomen.

Het kaIkgehalte van deze kalksteen is zeer variabel en ligt tussen 50 en 80% CaC03 • Een beeid van de variatie van het CaC03 gehalte geeft fig. 4.

In deze kalksteen komen geen duidelijke vuurstenen voor maar weI Si02 concentraties in vage knollen.

Fig. 1

In de jaren 1875-1929 werd te VijIen deze kalksteen in enkele groeven gedolven voor het vervaardigen van natuurcement.

Zone D + E bestaat uit een maximaal 30 m dikke Iaag fijnkorrelige witte kalksteen met veel kleine grillige donkere vuursteenknollen. In het meest oosteIijke gedeelte van Zuid-Limburg bevindt zich aan de basis van deze kalksteen een 1 tot 3 m dikke Iaag glauconietrijke kalksteen = zone D volgens Hofker (1966), Cr3" naar UhIenb roe k (1912). Hoger in het profiel kunnen in deze kaIksteen glauconiethoudende Iagen voorkomen. Het CaC0 3 ge-

TABLE 3 SubdivIsIOn Kunrade and Maastncht limestone after U hie n b roe k (1912) and H 0 f k e r (1966).

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Ho'ker Hofk4!lr Uhlenbroek Uhlenbroek 119661 11966) (1912) 0912)

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54 W.M. FELDER

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Lithological ~ section

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halte van deze kalksteen ligt tussen 80 en 90%. Het vuursteengehalte is vrij hoog en ligt tussen 12 en 13%. Gezien hun kleine en grillige vorm zijn de vuurstenen moeilijk uit de kalksteen te verwijderen.

Zone F bestaat uit een maximaal 20 m dikke laag fijn tot grofkorrelige witte kalksteen met veel grote en kleine donkere vuursteenknollen.

Deze kalksteen is vooral goed bekend in het meest westelijke deel van Zuid-Limburg. Hij bestaat uit een 15 tot 18 m dikke ~'lag met regelmatige donkergrijze vuurstenen.

Er zijn 23 vuursteenhorizonten in te onderscheiden. Meer naar het oosten is de kalksteen fijnkorreliger en ontbreken de duidelijke herkenbare vuursteenhorizonten. Lithologisch be staat er dan weinig of geen verschil tussen de foraminiferen zone's E en F (H 0 f k e r 1966). In het westelijk deel van Zuid-Limburg ligt het gehalte CaC0 3 tussen 85 en 99%. Het vuursteen gehalte bedraagt ca. 18-20%. Van meer oostelijk zijn geen analysen bekend. Zeer waarschijnlijk is het kalkgehalte iets lager en het vuursteengehalte ongeveer gelijk.

KUNRADER KALKSTEEN

U hIe n b roe k (1912) plaatste het grootste gedeelte van het Kunrader kalksteen als Ma onder de Maastrichtse kalksteen (Mb, Me en Md), tabel 3. Het hoogste fossielrijke gedeelte, bij Kunrade, stelde hij gelijk aan het Md.

H 0 f k e r (1966) stelde op basis van zijn foraminiferen onderzoek het grootste gedeelte van de Kunrader kalksteen gelijk aan het Mb van Uhlenbroek. Aleen een groot gedeelte van het profiel bij Kunrade met het Md van Uhlenbroek. Voor de kalkstenen in het oosten van Zuid-Limburg gebruikte Hofker echter een afzonderlijke codering, tabel 3. Recent lithologisch onderzoek, aan de hand van nieuwe ontsluitingen heeft echter aangetoond, dat de lithologische opbouw niet in overeenstemming te brengen is met de zonering van Uhlenbroek en Hofker. Het is dan ook te verwachten dat over dit reeds oude twistpunt het laatste woord nog niet gezegd is. In deze beschrijving is Kunrader kalksteen beschouwd als de lithologische ontwikkeling die bestaat uit een afwisseling van harde en zachte banken en ten oosten van Valkenburg aangetroffen wordt. Deze kalksteen bereikt ten zuiden van Kunrade en bij Ubachsberg een dikte van meer dan 60 m. Nergens is echter het voIledige kalksteenpakket aanwezig. De opbouw van deze kalksteen is zeer variabel en verschilt van plaats tot plaats. Aan de basis komt in de regel een in dikte wisselend pakket kalksteen voor, bestaande uit onregelmatige harde banken afwisselend met zachte glauconiet- en kwartszandrijke banken (zone G van Hofker). De dikte hiervan kan varieren van enkele meters tot meer dan 10 m. Hoger in het profiel gaan de onregelmatige harde banken over in meer of minder knolvormige ontwikkeling zonder een duidelijke bank te vOimen. Dit pakket is plaatselijk meer dan 50 m dik. Hierboven voIgt weer een duidelijke afwisseling van harde en zachte banken. Plaatselijk is een gedeelte van de zachte banken als grof fossielgruis ontwikkeld. Aan de top van de Kunrader kalksteen bevindt zich op enkele plaatsen nog een pakket harde en zachte banken. Deze bestaan, in tegenstelling met de meer gele en geel-grijze kalksteen, uit wit-gele grofkorrelige kalksteen, die weinig van de meer westelijk bekende Maastrichtse kalksteen verschilt.

Zowel in het basis- als het hoogste gedeelte zijn vuursteenknollen bekend, die echter steeds een ondergeschikte rol vervullen. Het kalkgehalte is zeer variabel. Van de harde


banken en knollen varieert dit van 90 tot 98% CaC0 3 ,

terwijl de zachte banken in enkele gevallen minder dan 50% en zelden meer dan 80% CaC0 3 bevatten. De dikteverhouding harde tot zachte banken is zeer wisselend. In de omgeving van Kunrade bestaat ca. 25% van het ontsloten profiel uit harde kalksteen, terwijl dit in de omgeving van Bocholtz tot 90% bedraagt.

MAASTRICHTSE KALKSTEEN

V hie n b roe k (I912) deelde het "Maastrichtse Krijt" in vier lithologische eenheden in (Ma, Mb, Mc en Md), tabel 4. Zoals boven reeds is aangehaald beschouwde hij het grootste gedeelte van de Kunrader kalksteen als liggende onder de Maastrichtse kalksteen. Hierbij maakte hij de aantekening dat deze in de St. Pietersberg zou ontbreken.

TABEL 4

Uhlenbroek (1912) Hofker (1966)

R

f--------Q

------- - ---P

Md f- - - - - - - - - -N

r-----------M

----------L

------------ ------------Me K

---------- ------,-----Mb

r--------- J

H

f-----------G

H 0 f k e r (1966) heeft op basis van zijn foraminifer en onderzoek een zone ring opgesteld die verder gaat dan de vierdeling van Vhlenbroek, tabel 4. Hetgeen bij de beschrijving van de Kunrader kalksteen is gezegd, geldt eveneens voor de Maastrichtse kalksteen. Ook hier is uit recent onderzoek gebleken dat de lithologische opbouw van het Ma en Mb van Vhlenbroek en de zone ring G tim J en 0 van Hofker niet in overeenstemming te brengen zijn met de lithologische opbouw. Bij de beschrijving van de Maastrichtse kalksteen beperk ik mij dan ook tot de kalkstenen welke voorkomen boven de Gulpense kalksteen tot en met de zone R van Hofker, in het gebied tussen Maas en Geul.

Het complex van de zone's G, H, I en J is zeer variabel

van opbouw en dikte. Aan de st. Pietersberg, waar Hofker deze kalksteen verdeelde in zone H en I, bedraagt de dikte ca. 20 m. Naar het oosten neemt de dikte snel toe. Bij Bemelen bedraagt zij ca. 45 m en bij Valkenburg minstens 70 m. Vit de lithologische opbouw is bekend dat deze diktetoename plaats vindt in het onderste gedeelte van het pakket. De bovenste 15 m zijn in het gehele gebied vrij uniform van opbouw en bestaan uit een wit-gele grofkorrelige kalksteen met vrij veel licht-grijze vuurstenen, die 6-12% van het geheel uit kunnen maken. Het kalkgehalte is hoog. Met uitzondering van het basale deel komt dit zelden onder 96% CaC0 3 • Het onderste gedeelte van het pakket dat aan de st. Pietersberg maximaal 3 m dik is, vertoont naar het oosten, gelijk met de diktetoename een geleidelijke verandering. In de omgeving van Bemelen bestaat dit gedeelte nog overwegend uit grofkorrelige grijs-witte kalk met kleine grillige donker- en vooral lichtgrijze vuursteenknollen. In de omgeving van Valkenburg is deze kalksteen fijnkorreliger en grijs-geel van kleur. Duidelijke vuurstenen ontbreken bijna geheel. Hun plaats wordt ingenomen door zeer vage, moeilijk van de omringende kalksteen te onderscheiden SiOl concentraties. In het onderste gedeelte van deze kalksteen zijn in de omgeving van Valkenburg reeds duidelijke harde banken te onderscheiden, terwijl hoger in het profiel vee! harde knollen voorkomen. Het kalksteengehalte van deze kalksteen is zeer variabel. Aan de St. Pietersberg varieert dit tussen 90 en 97% CaC0 3 , bij Bemelen tussen 77 en 90%. In de omgeving van Valkenburg kan het kalkgehalte in sommige gedeelten van het profiel teruglopen tot minder dan 50%, terwijl in de kalkrijke lagen een maximum van ca. 90% bereikt kan worden. Zeer waarschijnlijk is een groot gedeelte van de niet kalkbestanddelen "terug te voeren" op de fijn verdeelde SiOl concentraties.

Zone K bestaat uit een 5 tot 15 m dikke laag grofkorrelige wit-gele kalksteen met enkele verspreide vuursteenknoll en. Het kalkgehalte is zeer hoog en komt zelden onder 98% CaC0 3 •

Zone L en M bestaat uit een ca. 20 m dikke laag grofkorrelige, wit-gele kalksteen met vrij veel zeer grofkorrelige fossielgruislagen welke voor een groot dee! uit resten van bryozoen bestaan. Aan de basis van dit fossielgruis komen veelal harde kalkbanken (hard-grounds) voor. Het kalkgehalte is zeer hoog en komt ze!den onder 96% CaC0 3 • Deze kalksteen bevat geen vuursteen.

Zone N is beperkt tot een klein voorkomen in de omgeving van Geulhem en is van weinig betekenis.

Zone P bestaat uit een tot 10 m dikke laag grofkorre!ige wit-grijze kalksteen met weinig glauconiet en enkele harde kalksteenknollen. Het kalkgehalte is zeer hoog en bedraagt ca. 97% CaC0 3 •

Zone Q en R bestaan uit een in dikte wisselend, maximaal 40 m dik pakket kalkstenen. Van deze, alleen in boringen aangetroffen kalksteen, zijn geen analysen bekend.

58 W.M. FELDER

BOVEN-KRI1T KALKSTENEN ALS GRONDSTOF

De winning van grondstoffen, uit het Boven-Krijt van Zuid-Limburg, gaat terug tot het Paleolithicum toen in de omgeving van Rijkholt-St. Geertruid, aan of dicht onder de oppervlakte, vuurstenen uit de kalksteen gedolven werden voor het vervaardigen van gereedschappen. In het vroege Neolithicum, ca. 3150 v. Chr., had de vuursteenwinning zo'n omvang aangenomen dat de winning van aan of dicht onder de oppervlakte voorkomende vuurstenen niet meer voldoende was. Men ging geleidelijk over tot het aanleggen van mijnen. Na het Neolithicum heeft het gebruik van vuurstenen zich in Zuid-Limburg beperkt tot locale bouwsteen en voor wegverharding. Gedurende een korte peri ode zijn in

o !

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• '!uarnes in Maas;nchll/mes/one ~ + <J",arr/l!s in /(t/nrau'e limes/uno I:

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-+- 'It/arnes //7 Gt/I,oen limes/une ~ 'lI

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de omgeving van Vaals en Vijlen verweerde vuurstenen uit het vuursteeneluvium afgegraven voor de chamotte indus

trie. Een poging om in de omgeving van Cadier en Keer vuurstenen te winnen voor het bekleden van maaltrommels is eveneens op niets uitgelopen. De kalksteenwinning is mogelijk reeds op gang gekomen voor onze jaartelling. Plinius vertelt reeds dat de Ubii, een volksstam in het oude Aartsbisdom Keulen, een kalkaarde, op een die pte van drie voet, uit de bodem haalden om het land te bemesten. In de eerste eeuwen van onze jaartelling, tijdens de Romeinse overheersing, stond de kalksteenwinning reeds op een hoog peil. Bouwstenen werden gedolven in Kunrader- en Maastrichtse kalksteen. Verder kenden de Romeinen het gebruik van losse kalksteen als meststof en het branden van kalk-

Fig. 5 ReView of quarries In Maastncht-Kunrade and Gulpen limestone.

steen voor pleisterkalk. Vanaf de Romeinse overheersing tot omstreeks het midden van de 1ge eeuw is in het hele patroon van de kalksteenwinning weinig of geen verandering gekomen. Een verandering in deze situatie werd ingeluid toen even na het midden van de 1ge eeuw, in Vijlen een cementfabriek in bedrijf genom en werd die kalksteen uit de Gulpense kalksteen ging gebruiken voor het op grote schaal vervaardigen van cement. De cementindustrie heeft zich, nadat in 1928 de E.N.C.I. te Maastricht in bedrijf gesteld werd, ontwikkeld tot de grootste verbruiker van kalksteen . Met de vestiging van het stikstofbindingsbedrijf van de

KALKSTENEN VAN HET BOVENKRJJT IN ZUID-LIMBURG EN HUN EXPLOITATIE 59

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Fig. 6 Review of the output of buildmgstones from the MaastrIcht limestone m m3 from 1905-1970.

Staatsmijnen (thans D.S.M. N.V.) te Geleen, in 1930, werd weer een nieuwe grootverbruikersmarkt geopend.

Ondertussen had de industrialisatie met behulp van verbeterde wegen, waterwegen en spoorwegen een groot gedeelte van de benodigde landbouw- en pleisterkalk naar buitenlandse leveranciers overgeheveld. Het ontbreken van een of meer grote bedrijven met kwalitietsproducten had geen goed gedaan en betekende het einde van deze industrie. De een na de andere groeve en kalkoven werd verlaten en verviel tot een ruine. Het enige dat ons bleef is dat het hele kalksteengebied bedekt is met oude vervallen groeven (fig. 5). AIleen in de oorlogsjaren 1914-1918 en 1940-1945 en direct daarna, toen de aanvoer van buitenlandse kalk stagneerde kreeg de plaatselijke kalkindustrie weer een kans. Oude en nieuwe groeven en ovens kwamen kortstondig in bedrijf. Ook de winning van bouwstenen is door rationeler te verwerken nieuwe product en van de markt gedrukt. Zowel de winning van bouwstenen uit de Kunraderals de Maastrichtse kalksteen is na 1962 vrijwe1 geheel weggevallen en beperkt zich momenteel tot minder dan 500 m3

per jaar nodig voor restauraties. Productiecijfers over de gedolven bouwstenen uit de Kunrader kalksteen zijn niet bekend. Van de bouwstenen uit de Maastrichtse kalksteen beschikken we over productiecijfers vanaf 1905. Een overidcht hiervan is gegeven in fig. 6. De langzaam op gang gekomen verandering is na goed 100 jaren vrijwel definitief geworden. Van de meer dan 120 open- en 27 ondergrondse groeven die in 1917 nog in gebruik waren is vrijwel geen meer in bedrijf. De behoeften waarin zij voldeden zijn door buitenlandse- of een van de vier grote goed geoutilleerde groeven in Zuid-Limburg overgenomen (fig. 7-8). Een overzicht van de productie van deze vier groeven is weergegeven in fig. 9.

GEBRUIK V AN KALKSTEEN

De be1angrijkste verbruikers van de kalksteen die mo-

menteel wordt afgegraven zijn in volgorde van grootte: de cementindustrie de fabricage strooibare vaste, meststoffen de landbouwkalk.

Buiten deze wordt een kleine hoeveelheid (5%) verwerkt in andere industrieen. Afhankelijk waarvoor de kalksteen gebruikt wordt is men gebonden aan bepaalde kwaliteitseisen. Vooral bij de strooibare vaste meststoffen liggen de kwaliteitseisen zeer hoog en moet het CaC0 3 gehalte minimaal 92% bedragen. De cementindustrie kan ook kalksteen met een lager CaC03 gehalte verwerken mits dit binnen bepaalde grenzen blijft en de kalksteen in grote hoeveelhe den met een constante samenstelling verkregen kan worden. Bij de kleinere afnemers lopen de kwaltteiten sams zeer uiteen en zijn geen algemene richtlijnen van toepassing maar dienen op iedere verbruiker afgestemd te worden.

VOORKOMEN EXPLOITEERBARE KALKSTEEN

Uitgaande van de kwaliteitseisen welke moment eel aan de kalksteen gesteld worden en het geologische voorkomen, komt in Zuid-Limburg alleen de Maastrichtse en een gedeelte van de Gulpense kalksteen in aanmerking voor eventuele exploitatie op grote schaal. Buiten de kwaliteitseisen en het geologisch voorkomen wordt de mogelijkheid van exploitatie beinvloed door een aantal andere factoren zoals cultuurtechniek, landschaps- en natuurbescherming, topografische gesteldheid, afdek en de stand van het grondwater. Wordt met al deze factoren zo veel als mogelijk rekening gehouden dan kan het kalksteenvoorkomen ten oosten van de Maas in vier grote gebieden verdeeld worden (fig. I). Het gebied ten westen van de Maas, dat zich beperkt tot de St. Pietersberg en in exploitatie is bij de N.V. E.N.C.I. te Maastricht is in deze buiten beschouwing gelaten.

Gebied I - omgeving Ubachsberg In het gebied van Ubachsberg, waar hoofdzakelijk

60 W.M. FELDER

Fig. 7 Foto nO 5461, R.G.D./G.B. L.R. Funcken. Quarry Curfs near Geulhem. Highest part of Maastricht limestone, with overburden of 42 m and 26 m limestone.

Fig. 8 Foto nO, R.G.D./G.B. L.R. Funcken. Loadmg of limestone m quarry Nekaml, Rooth near Margraten.


4,000.000 10'"

limt!stont! product ion for olht!r purpost!S

limt!stont! production for ct!mt!nl industry

JOOO DOOlon

1 000.000 tOfl

lOOO 000 Ion

FIg. 9

Kunrader kalksteen voorkomt is wegens het lage CaC0 3

gehalte en de afwisseling van harde en zachte lagen vooralsnog geen lonende exploitatie mogelijk.

Gebied II - Gulpen en Vaals In het gebied tussen Gulpen en Vaals, waar alleen Gul

pense kalksteen voorkomt, is wegens een te laag CaC0 3

gehalte, een te geringe dikte of andere bezwaren geen lonende exploitatie mogelijk.

Gebied III - Zuidelijk van Margraten In het gebied ten zuiden van Margraten, tussen Maas en

Gulp, is exploitatie mogelijk in het meest noord-westelijk deeI mits de kwaliteitseisen niet te hoog worden gesteld. De aanwezige kaIksteen bestaat voornamelijk uit Gulpense kaIksteen, zone C, E en F (Hofker) en Maastrichtse kaIksteen, het Iage CaC0 3 gehalte, ten gevolge van moeilijk of niet te verwijderen fijn verdeeIde vuursteen, is de bruikbaarheid van deze kalksteen beperkt. Uitgaande van de genoemde maatstaven is binnen dit gebied exploitatie mogeIijk tot een maximum van ca. 400.106 ton kalksteen met een gehalte van 80-90% CaC03 . In hoeverre ook exploitatie mogeIijk is onder de grondwaterspiegel is onbekend.

Gebied IV - Noordelijk van Margraten In het gebied ten noorden van Margraten zijn de verhou

dingen voor exploitatie verreweg het gunstigst. Hier komt vooraI het gebied westelijk van de lijn Valkenburg-Margraten in aanmerking. Binnen dit gebied is te rekenen met ca. 250.106 ton Maastrichtse kalksteen met een grove korreI en meer dan 92% CaC03 boven de grondwaterspiegel. In het meest noord-westelijke gebied komt hierbij nog ca. 80.106 ton overeenkomstige kalksteen onder de grondwaterspiegel. Buiten deze hoogwaardige kalksteen is binnen dit gebied te rekenen met ca. 50.! 06 ton grofkorrelige Maastrichtse kalksteen met 70-90% CaC0 3 • Onder de grondwaterspiegel bevindt zich binnen het betreffende gebied ca. 300.106 grofkorrelige Maastrichtse kalksteen met 70-90% CaC03 •

.:.\

:~ .\ .:.:

KALKSTEENEXPLOITATIE IN DE TOEKOMST

Uitgaande van de huidige marktverhoudingen, de kwaliteitseisen, alsmede de tot nu toe gebruikelijke methode van exploitatie, is te verwachten dat slechts een gedeelte van de expIoiteerbare voorraad kalksteen benut zal worden. Hoe groot deze hoeveelheid is kan moeilijk bepaald worden. Het is echter niet uitgesloten dat deze minder dan de heIft van de werkelijke voorraad bedraagt.

Mocht de exploitatie zich in de toekomst beperken tot de kalksteen boven de grondwaterspiegeI in gebied IV dan is met een gelijkblijvende behoefte en marktverhouding te verwachten dat de exploiteerbare voorraad over 50 jaren verbruikt is.

Of het mogelijk is tot een optimaaI verbruik van de voorraad te komen is afhankelijk van de ontwikkeling in de kaIksteenexpIoitatie en de marktverhoudingen. Indien de exploitatie zoveel mogelijk geconcentreerd kan worden tot een beperkt aantal groeven en een weg gevonden zou kunnen worden dat verbruikers aangepaste kwaliteit verwerken dan is niet alleen een optimale exploitatie van de totale voorraad mogeIijk, maar zouden ook de kosten aanzienlijk kunnen worden verlaagd.

REFERENCES

Anomem, (1946) - Rapport mzake opsponng, inventansatie en toepassmg van oppervlakte-delfstoffen in Nederland. Meded. Geo!. Stichtmg Nwe. Ser. 1.

Felder, W.M. (m druk) - LithostratIgrafische mdeling van het Boven-Knjt in Zuid-Limburg en aangrenzend gebied.

Habets, J. (1887) - Over de vraag of de LImburgsche mergelsteen door Plimus wordt besproken. Vers!. en Ned. Kon. Akad. Wetenschappen.

Habets, J. (1893) - Over oude (Romemse) mergelputten. Vers!. en Ned. Kon. Akad. Wetenschappen, Afd. Letterkunde 3e reeks e ' , 9 deel, Amsterdam.

Heerding, A. (1971) - Cement in Nederland, IJmUlden.

62 W.M. FELDER

Hofker, 1. (1966) - Meastrichtlan, Danian and Paleocene Foraminifera. The Foraminifera of the Type-Maestrichtian in South Limburg, Netherlands, together with the foraminifera of the underlYing Gulpen Chalk and the overlying calcareous sediments; the Foramimfera of the Denske Kalk and the overlying greensands and ciyas as found in Denmark. Paleontographlca, Suppl. Bd. 10 Stuttgart.

Martens, A.H.W. (1961) - Van 1810 Administration des Mines tot 1960 Staatstoezicht op de Mijnen. Bijl. verslag InspecteurGeneraal der Mijnen over het jaar 1959.

Romein, B.1. (1963) - Het gebrmk van Zmd-Limburgse Kalksteen. Jaarverslag Geol. Stlchting.

Uhlenbroek, G.D. (1912) - Jaarversalg Rijksopsponng van Delfstoffen in Nederland over 1911-1912.


THE DISCOVERY OF URANIUM AT HAAMSTEDE (NETHERLANDS)

H.M. HARSVELDT 1)

ABSTRACT

In four borings carried out by the "Delta Dienst Rljkswaterstaat"* on the island of Schouwen (W. Netherlands) three layers of phosphonte nodules were encountered between approximately 123 m and l37.5 m below the surface.

The phosphorite nodules showed natural gamma radiation caused by then uramum content. The uranium present m the nodules was mvestigated by means of the mass-spectrometric isotope dilutIOn method.

In addition spectrophotometnc and fluorometnc determinatIOns were carried out and the spontaneous gamma activity was measured. In order to obtain an idea of the distributIOn of these nodules, samples of other borings were re-examined.

The 33 uranium analyses showed percentages between 0 and 200 ppm U23~ i.e. a maximum of 0.02% U 235 which is insufficient to consider an economic production of uranium.

The mvestlgation was extended to the other islands of Zeeland, where in several bonngs phosphorite nodules were found. Uranium determinations here also showed a low grade. The highest grade found amounted to 291 ppm (0.03%), discovered in a boring on the West coast of Wa1cheren.

Also phosphorus investigations were carried out.

SAMENVATTING

In vier bonngen, Ultgevoerd door de Deltadlenst van de Rijkswaterstaat op het elland Schouwen, werden drie lagen met fosfonetknollen aangetroffen tussen 123 en 13 7 ,5 m beneden maaiveld.

De m de boorgaten uitgevoerde metingen van natuurlIjke gammastralen wezen op de aanwezlghe1d van uramum in de fosfonetknollen. De hoeveelheid uramum werd door massa spectrometrische ISO

topen verdunnmg vastgesteld. Hiernaast werden nog spectrofotometnsche en fluorimetnsche bepalIngen gedaan en werd eveneens de spontane gamma activitelt bepaald.

Met het doel een overzicht te verkrijgen over de verspreidmg van deze knollen werden monsters Ult dezelfde formatle van andere boringen op het elland Schouwen heronderzocht op fosfonetknoj:. len. Hlerbij werden op Schouwen in totaal l3 boringen met fosforietknollen gevonden.

33 uramum analyses werden uitgevoerd waarbij percentages van 0-200 ppm U 23S, d.w.z. een maximum van 0.02% U235, werden

* Service for the Delta project of the Netherlands Ministry of PublIc Works. 1) RIJks Geologische Dienst, Spaarne 17, Haarlem, The Netherlands.

gevonden. Dlt gehalte IS onvoldoende om exploltatie te overwegen. Het onderzoek werd voortgezet op de andere Zeeuwse ellanden.

In de bormgen, die stra tlgrafisch diep genoeg waren, werden eveneens fosforietknollen gevonden. Ook hler vertoonden de analyses slechts een laag percentage uranium. Het hoogste gehalte werd gevonden in een bonng op de Westkust van Wa1cheren, nl. 291 ppm (0.03%).

Naast uranium analyses werd ook het fosforgehalte onderzocht.

The starting point of the investigation into the presence of uranium was the report made to the State Survey of the discovery of phosphorite nodules containing uranium found in four borings drilled by the Ministry of Public Works on the island of Schouwen in the province of Zeeland.

The geophysical borehole measurements, in particular the natural gamma radiation, provided exact information on the depth and thicknesses of the layers encountered.

GEOLOGICAL SETTING

At Haamstede airfield on the island of Schouwen three layers containing phosphorite nodules were encountered at a depth between approximately 123 m and 137.5 m below surface.

The results of a lithologic and stratigraphic examination of the strata in the boreholes are given below (fig. 1).

Holocene sandy channel deposits occur from surface to about 44 m depth. These deposits consists of fine to medium coarse sands, rich in lime. A considerable amount of shell grit occurs in the sands. Two distinct shell horizons were traced at 7-10 m and 35-26 m (All depths are approximate).

In the sand body two intercalations with fine sandy clay layers occur at 12.5 m and 16 m.

The Pleistocene deposits extend to about 104 m, conSisting of fine to medium coarse sands with local shell grit and clay layers. Throughout intercalations of silty clay layers of about 1 m thickness occur.

64 H.M. HARSVELDT

.----- ----.--- ---SVRrACCr=,-=,,,.------ -

",'. '--'-\'-c---

=-=---~-----

Fig. I LithologiC log of bonng 42B-20-3 with geophysical measurements.

Two thicker sandy clay layers occur between 59-61 m and 94-101 m. The basal part of the Pleistocene, lying between 91-104 m is known as the Merksem Sands.

One distinct shell horizon occurs at a depth of 54-56 m.

The tertiary deposits begin at about 104 m depth. The borings at Haamstede airfield penetrated successively the Kallo Sands (U. Pliocene) , the Kattendijk Sands (L. Pliocene), the Deurne Sands (U. Miocene), the Antwerp Sands (M. Miocene), and the "Boomsche Klei" (M. Oligocene)

The Kallo Sands are developed as rather silty, medium

fine to medium coarse sands. Shell fragments and some fine gravel occur. At 107-108 m depth a clay layer was found in one of the boreholes which, according to the geophysical indications, has very probably not the same facies development as seen in the other boreholes (fig. 2) .

The Kattendijk Sands are medium fine to coarse and contain much shell grit. The Kattendijk Sands occur from 117-123.5 m.

Fig. 2

~

~I ······1···'· .. : \./"',

~~ -'---",.-- '--, ~

~~ -.---"''''---.--

1 1

, ,.' I '.: ,:~n\ i\ r, ~ I ~ I \ \J I 1\

I " \' 1 r \ \ r \ v I

~ ~

FaCies develop men t of the clay layer 111 the Kallo Sands

THE DISCOVERY OF URANIUM AT HAAMSTEDE (NETHERLANDS) 65

The Deurne Sands cover the interval between 123.5-131 m, consist of medium fine glauconite sands with intercalations of shell grit.

At the top of this deposit lies the third phosphorite nodule layer. The Antwerp Sands are found between 131-155 m. The upper 13 metres of these sediments consist of fine to medium grained sands with glauconite.

In this part of the sands the second and first phosphorite nodule layers occur. The basal parts of the Antwerp Sands are very rich in glauconite.

OTHER PHOSPHORITE OCCURRENCES ON THE ISLAND OF SCHOUWEN

In order to obtain an impression of the distribution of the phosphorite nodules as found at Haamstede, all borings on the island that might conceivably have encountered these nodules were re-examined. This investigation revealed that nodules had indeed been noted on previous occasions, but were not recognized as such. These nodules were simply described as "stones". These "stones" which were in fact phosphorite nodules were traced in nine borings. An attempt was made to correlate the "stones" encountered with the three phosphorite nodule layers discovered in Haamstede. Since no measurements of the natural gamma radiation were available this proved to be difficult. Another aspect that made a correlation difficult was the fact that at the time these boreholes were drilled the possibility that more than one layer of "stones" might be present was not taken into account. Caving of the "stones" from an upper phosphorite layer could suggest that one thick continuous layer is present, but also that there may be more than one layer.

From the available data it may be concluded that in the other nine boreholes there was likewise more than one phosphorite nodule layer.

With the help of stratigraphical profiles the area in which phosphorite nodules on Schouwen occur was delineated. An attempt was also made to contour each nodule layer separately (fig. 3A, B, C). In addition an effort was made, using the information from the profiles, to ascertain the stratigraphical position of the deposit.

The most reliable profile for this purpose is the airfield profile (fig. 4), which shows that, with a few exceptions probably due to inaccurate sampling, the first phosphorite nodule layer is restricted to the Antwerp Sands, the second layer to the boundary between the Antwerp Sands and the Deurne Sands, and the third layer to the boundary between the Deurne Sands and the Kattendijk Sands.

PETROGRAPHICAL DETERMINA nONS

Determinations with regard to the composition of the nodules were independently made by the "Isotopen Geo-

A

B

420-38

c

Fig. 3

I I

/

.f.ZG-2Z

42B _ 7. Boorpunt met archlef nr R G D Bormg With record number of R G 0

o 1 5km

~Haamstede

42G-22

42B - 7.Boorpunt met archlef nr R G D Bormg With record number of R G D

L-L ~m

12S

~42G-22

42B _ 7- Boorpunt met archlef nr R G 0 Boring With record number of R G D

O~~2_~~m

Contour on top of fust (3A), second (3B) and thud (3C) phosphonte layer at Schouwen_

logisch Laboratorium" (Amsterdam), the State Geological Survey (Haarlem) and the State Universities of Leiden and Utrecht.

The phosphorite nodules consist of light green glauconite globules and subangular to rounded quartz grains (with subordinately some feldspar grains), embedded in a brown cryptocrystalline matrix consisting of apatite. In the matrix tiny sericite flakes and some ore minerals are present. As accessory minerals chlorite, zircon, garnet, epidote, titanite, hornblende and probably collophane and francolite are pre-

66 H.M. HARSVELDT

WZW ONO

Sl'IIl jpUnt rI-11' enltl·11I"

']6·25·J5 ']6·]0.6 ']B·]0·5 ']B.]O.) ";;v:t-r-------------"t-----I

15m

so KWARTAIR

" Ie<>

"' ::::·:···~··:···:··:· · ·~··:· ~~~::::;:l:::::1 F~'~--- ........ ... ::::::: .... .... ....... w - ... .. , ... , .. ~. . . .. .. . " .. " .. . ~ .~ . .. i . . . ,

ISO

" <.~.~ '.~:.-:::~-::::»":~~...;:...~:»:~~:-~~;~.'8:::$.;~<~::_~,~. , .. >~.:..;.;.. .•• ;;;':..;,:::::;.,«:.. (} j!, 10 10 ~O SOm

I::':'::::: j Z .. nden "~,,, K.allo .: . . .. :' s.and'~ K~ 11o

FIg. 4 StratIgraphIc sectIOn near the aufleld of Schouwen.

sent. About 30-40% of the nodules consists of apatite. The uranium is bound to the apatite.

DETERMINATION OF THE URANIUM CONTENT OF THE NODULES

Several methods were used for the analyses of the uranium content.

Routine determinations were carried out by means of fluorescence. The necessary standard curves were obtained

TABLE 1 Some uralllum-analyses at Schouwen

Nr. Depth III m MaterIal

bOrIng

42B-20-3 124 -125 Nodule 42B-20-3 125 -126 Nodule 42B-20-3 12(, -127 Nodule 42B-20-3 127 -128.5 Nodule 42B-20-3 12S -129 Nodule 42B-20-3 129 -130 Nodule 42B-20-3 129 -132 Nodule 42B-20-3 131 -132 Nodule 42B-20-3 132 -135 Nodule 42B-20-3 135 -138 Nodule + shell fr. 42B-20-3 136 -137 Nodule 42B-20-3 138 -141 Nodule + shell fr. 42B-3 109.1-110.7 Nodule 42B-5 109.8-113.8 Nodule 42B-6 105 -105.1 Nodule 42B-7 102.6-110 Nodule 42B-32 117.3-118.1 Nodule 42B-40 133 -134 Nodule

by means of mass-spectrometric isotope dilution analyses. The measurements were performed in the "Z.W.O. Isotopen Laboratorium" in Amsterdam, with the assistance of scientists of the "Vening Meinesz Laboratorium voor Geophysica en Geochemie" at Utrecht and the "Centraal Laboratorium T.N.O." of Delft. In addition spectrophotometric and fluorometric determinations were performed together with measurements of the spontaneous gamma activity.

Since three laboratories were independently engaged in the determinations of the uranium content meaningful comparisons proved to be possible.

A bulk sample was prepared as a reference sample for the three laboratories from nodules collected from the interval 129-132 m of boring 42B-20-3. These nodules belong very probably to the third layer. The sample was also used an an external standard for the X-ray fluorescence measurements.

The uranium content of this sample was determined by mass-spectrometric isotope dilution and contained 116.5 ppm uranium. The amount of uranium found so far is too small to consider production; to be of economic interest the content has to be more than 500 ppm.

In total 33 analyses were made. The uranium contents were between just below 6 ppm and 199 ppm (table 1).

RESERVE ESTIMATES

The information obtained from the scanty data is insufficient to attempt to estimate the amount of nodules that might possibly be present on the island of Schouwen.

PRODUCTION PROSPECTS

With regard to the method of production several sugges-

U-content III ppm Matnx corr. for Rontg.fl.

Isotope dll. Rontg.fl.

124 0.90 132 0.96

6 1.105

128 0.96 6

11 0.91 5

116.5 standard 1.00 117 0.96 118 0.94 53.5 104

6 53.5 0.95 95 0.91

104 1.00 199 1.00 184.5 1.03 150.5 0.94 113.5 0.905


tions have been put forward of which the one described below is worthy of attention.

Conventional mining by means of shafts is not thought advisable in the Delta area.

The idea of leaching the ore as proposed by the Geological Institute of the State University of Utrecht, is based on a system of pumping diluted sulphuric acid (5%) into the phosphorite nodule layers by means of injection wells. The phosphorus and uranium are dissolved and the solution is recovered by means of production wells. This system implies that above and below the nodule layers an impermeable layer must be present te prevent the acid solution from flowing elsewhere. Well logs run in the holes drilled at the Schouwen airfield show that a good c'.ay layer is not everywhere present above the phosphorite nodules. Below the first nodule layer, however, an impermeable Boom Clay is present. Laboratory experiments carried out in the Vening Meinesz Laboratory at Utrecht showed that the 18 m thick shell horizon, directly overlying the nodule horizon III, neutralizes the sulphuric acid, forming at the same time an impermeable calcium sulphate layer.

PHOSPHORITE NODULES ELSEWHERE IN ZEELAND

A. Walcheren:

Phosphorite nodules belonging to the layers I, II and III have been found in fourteen borings on the island of Walcheren. Samples have been preserved of only five borings. The uranium content of these samples has been determined. The borings concerned are listed below:

The uranium content found is too low to consider an economic production.

In the stratigraphic profiles the phosphorite nodules have been indicated at the boundaries of the Kattendijk Sands and the Deurne Sands (layer III), the Deurne Sands and the Antwerp Sands (layer II) and about 5 metres below the top of the Antwerp Sands (layer I).

TABLE 2

no. bOrIng mUniCipality deptii m m

4SA-2 BIggekerke 29 -30 4SA-5 BIggekerke 33 4SA-45 GnJPskerke 32 48A-59 Lammerenburg 27.5-30 4SA-6-S Westkapelle 42 -43 4SA-24-3 Koudekerke 51 -52

4SC-41 Vhssmgen 35 -41.5 2S.5-35

4SC VlIssmgen 29.5-33 4SC-71 VlIssmgen 30 -50 4SD-37 Vhssmgen 24 -24.1 4SD-56 O. Souburg 24 -34 4SD-65 VlIssmgen 29 -31 4SA-46 Koudekerke 39 4SB-25 St. Lamens 36

Due to the irregular distribution of these sands, the occurrence of the phosphorite nodules is rather capricious (fig. 5).

Contour maps of the three phosphorite layers are given in fig. 6A, B, C.

B. Tholen:

In a boring with a total depth of 127 m on this island, the Kattendijk Sands were found between 93 and 106 m, the Deurne Sands between 106 and 107.5 m and the Antwerp Sands between 107.5 and 122.7 m. The boring ended in the Oligocene at a depht of 127 m.

Phosphorite nodules were present between 107.3 and 121 m, at the base of the Deurne Sands and in the Antwerp Sands. The nodules found belong to the layers II and 1. Determinations of uranium content gave the following information:

TABLE 3

Depth m metres Uppm

107.3-107.5 141.5 107.5-10S.6 128 10S.6-109 169 117 -l1S.5 90 117 -l1S.5 219 106 -l1S.5 178

C. Zuid Beveland:

Phosphorite nodules have been found in 12 borings on this island. Of only four borings sufficient material was present for uranium determinations. The highest values were found in a boring at Rilland Bath. Here nodules with an uranium content of 129 ppm were found at a depth between 76 and 80 m. Bone fragments discovered in the same intervals revealed an uranium content of 136 ppm. The nodules very probably belong to layer I.

layer

III III

I II III

III III III

stratigraphy

Quaternary Pliocene Pliocene KattendlJk KattendlJk Antwerp Antwerp Deurne KattendlJk Antwerp KattendlJk KattendlJk Kattendljk Pliocene Quaternary

Uppm

291 6-59

54.5-111 27.5- 77

68 H.M. HARSVELDT

42021-28.0- .

o 48A- 45

o 48A-46

..... .

MIDDELBURG 488-2>

o 488-28

0 69b- 40

481;45 80rrngen mel arcntefnummer RG D Borings with record number RGO

100

ZW I

48A6·8

KWARTAIR

o 1 2 J 4km

m m

Zan den van Kallo Kallo Sand50

Zanden van Kattendijk Kanend ijl( Sands

Fig. 5

Zanden van Oeurne Oeurne Sands

Zanden van Antwer-pen Antwerpen Sand$

O llgoceen Oligocene

o

NO r

42021-28

O' I 2 3 4km

Fo,loriedagen l. U en ill Phospnorite layers I. nand m

Fodorietknollen in de boringen Phosphorite nodules in the borings

Stratigraphic profile along the West coast of Walcheren.

D. Zeeuws Vlaanderen:

In Zeeuws Vlaanderen phosphorite nodules have been found in 45 borings. From eight borings still sufficient sam· pIes were available for analysis. The uranium content varies from less than 6 ppm to 134.5 ppm uranium maximum. The highest concentration was seen in nodules of a boring at Hontenisse at a depth between 14 and 16 m. The nodules are of Pliocene age.

E. Westerschelde:

In this estuary 56 borings discovered phosphorite nodules. Nodules from 14 borings have been analyzed on their uranium content. The highest values, too low, however, to be economically attractive, were found in the Western part of the Westerschelde in the triangle formed by the towns of Vlissingen, Terneuzen en Breskens.

The contents vary from 114 ppm uranium to 213 ppm uranium. The nodules belong to layers II and III and have been found between 20 and 35 m below sea level.

F. St. Philipsland and Noord Beveland:

Due to the lack of deeper borings, phosphorite nodules have not been found as yet.

DETERMINATION OF THE PHOSPHORUS CONTENT OF THE NODULES

In order to get an impression of the phosphorus content of the nodules, 12 determinations have been carried out within the province of Zeeland. The following percentages were found :

Commercial rock phosphate deposits usually contain 60-90% of tricalcium phosphate. Only at three locations this condition is approached in Zeeland (fig. 7).

As far as could be judged from the data obtained no relation between uranium content and phosphorus content has been detected .

REVIEW

The uranium level found at Schouwen is between approximately 100 ppm and 200 ppm, insufficient to consider an economic production. The same holds true for Walcheren (50-291 ppm), Tholen (90-219 ppm), the Westerschelde (100-200 ppm) and Zeeuws Vlaanderen (50-134 ppm) (fig. 8).

The layers containing the nodules appear to be discontinuous and their areal extent is probably rather unpredictable. This might be due either to inaccurate sampling or to local lack of nodules.

The latter possibility would fit in well with the biochemical hypothesis of Bushinsky which explains the ab-


A

B

-_ .. -'"

---

--- ... .?J' .........

'10- __

sence of phosphorite nodules by the fact that quartz and phosphate are mutually exclusive. The quartz content of the green sands in Zeeland is so high that the formation of the phosphates, according to Bushinsky's theory would not seem probable.

c

.......... .?.s .......

o

•

7

Fig. 6

Bar.ngen 8orlnl5

Bormgen met knoUtn van laag 3 8orlng~ wIth nodules of layer 3

o

Verbreldmg van de Zanden van KattendlJk en knollenlaag 3 DistributIon of the KattendlJk Sands and nodule layer]

ContourhJ" van de dltpte van knollenlaag 310m - NAP Contourhne of the depht of nodule layer] In m • NAl

Contour maps on top of fust (6A), second (6B) and phosphorite layer at Wa1cheren, With dlstnbution of Sands,Deurne Sands and Antwerp Sands.

LITERATURE

3 .. 11m

third (6C) Kattendljk

1. Bushmsky, G.J.: On shallow water ongIn of phosphOrIte sediments. "Dev. in Sed. - Vol. I - DeltaiC and shallow manne deposits" - Proc. 6th Intern. Sed. Congr. 1963, p. 62-70 .

2. R.U. Utrecht & T.H. Delft: Voorl0plg verslag over het voorkomen van uranium in de Nederlandse ondergrond, maart 1969.

3. R.U. Utrecht & T.H. Delft: Voorlopige beschouwmg over de winning van uranium en fosfaat uit de Nederlandse ondergrond, mel 1969.

4. Kemper, A. & G.A. v. Kempen: Bepaling van het uramumgehalte van een bodemmonster, Dlenstrapport, apn11969.

5. R.W.S. Deltadlenst & Reactor Centrum Nederland: Uraniumonderzoek Haamstede, Dlenstrapport, apn11969.

6. Z.W.O. Lab. v. Isotopen Geologie: Intenmrapport aan de R.G.D. betreffende het onderzoek van uramumhoudende fosforietknollen blJ Haamstede op Schouwen-DulVeland, Dlenstrapport, mel 1969.

7. ThIadens, A.A. & H.M. Harsveldt: Interimrapport betreffende de vondst van uraniumhoudende fosforietknollen op het elland Schouwen, Dlenstrapport, mei 1969.

70

TABLE 4

bonng location

42B-20-3 Schouwen 42B-40 Schouwen 49A-22 Tholen 48A - 6-8 Wa1cheren 48C-41 Walcheren 48D-56 Walcheren 48F-34 Z. Beveland 69b-33 Westerschelde 69b-31 Westerschelde 69b-32 Westerschelde 54B-46 Zeeuws Vlaanderen 55A-16 Zeeuws Vlaanderen 49B-190 W. Brabant

P% e--P2 05 0/ 0

FIg. 7 DIstnbutlOn of phosphorus analyses m Zeeland.

H.M. HARSVELDT

phosphorus-content percent of as % of weIght P weIght P2 0 S

~.88 11.17 6.00 13.74 5.68 13.01

11.00 25.19 5.96 13.65 6.37 14.59

13.64 31.23 5.76 13.19 8.82 20.20 5.28 12.09

11.85 27.13 5.90 13.6 5.82 13.33

percent of weIght Ca3(P04h

24.57 30.22 28.62 55.41 30.03 32.09 68.70 29.01 44.44 26.59 59.68 29.92 29.32

++ + + + +

++ + + + ",


• WITH PHOSPHORITE-NODULES (NO ANALYSIS)

o >190 PPM

.. 150-190PPM \m:~g·3 e,uB·3

o 100-150PPM

e 50-100PPM

.. 6 - 50 PPM

Cl4aD-S~ • • 1480 - 65 . . . .

0480-140

Fig. 8 DIstnbutlOn of uranium analyses m Zeeland.

8. Thladens, A.A. & RM. Harsveldt: Eerste rapport betreffende de stand van het onderzoek en de evaluatJe van de uraanvondsten blj Haamstede op het elland Schouwen, Jum 1969, Dwnstrapport.

9. van Voorthuysen, J.H.: StratJgraflsche beschouwmg betreffende het voorkomen van uramumhoudende fosfonetknollen m de MIOcene groenzanden van zUldwestehjk Nederland, aug. 1969, Dlenstrapport.

10. Z.W.O. Lab. v. Isotopen Geologie. Onderzoek uramumhoudende fosfonetknollen Haamstede, Dlenstrapport, sept. 1969.

11. Klmpe, W.F.M.: Petrograflsche beschnjvmg van enkele fosfoneten, dec. 1969, Dwnstrapport.

12. Bertoen-Brouwer, D.A.: Bhksemonderzoek van uranlUmvondsten op Schouwen-DUIveland, "K.N.A.G. Geogr. Ti]dschr. III", 1969, nr. 4, p. 362-364.

13. Z.W.O. Lab. v. Isotopen Geologie: UranIUm-analyses aan fos-

++ + + . +

.+ + + ..

Xx

fonetknollen en ander matenaal ult bonngen m Z.W. Nederland, maart 1970, Dienstrapport.

14. Harsveldt, H.M.: De uraanvondst bl] Haamstede, apnl 1970, Dlenstrapport.

15. Centnial Lab. T.N.O .. Bepahng van het uraangehalte m fosfonetknollen d.m.v. gammaspectrometrie, onderzoek naar radlOactJef evenwlcht, apn11970, Dlenstrapport.

16. Harsveldt, H.M.: Uraanhoudende fosfonetknollen. Toelichtmgen GeoL Krt. v. Nederland - blad Schouwen-DUIveland, 1970, biz. 84-92.

17. Harsveldt, RM.: The discovery of uranIUm at Haamstede (Netherlands), 1971, Dwnstrapport.

18. Toor, P. van: Uraanhoudende fosfoneten. Toehchtmgen GeoL Krt. v. Nederland - blad Walcheren, 1972, biz. 83-93.


PURE MIOCENE QUARTZ SANDS IN SOUTHERN LIMBURG, THE NETHERLANDS, STRATIGRAPHICAL OCCURRENCE AND REGIONAL DISTRIBUTION

O.S. KUYL 1)

SUMMARY

Quartz sands in sou them Lim burg, characterized by an iron content of less than 0.01% Fe203, and an AI2 0 3 content of less than 0.025%, are found III two areas: A. North of the Feldblss fault near Eygelshoven III an area of about

3 km2 .

B. North of Heerlen on the fault block between the Feldbiss and Heerlerheide faults III a region of about 11 km2.

Up tIll now only the sands in region B have been explOIted mainly in order to be used as a raw material of the crystal glass Illdustry.

There are indicatIOns that the quality of the sands towards the southeastern part of region B deteriorates because of the absence of the Morken browncoallayer. This layer is thought to have prevented the infiltration of Hon-bearing solutions percolating through the overlymg Pleistocene sedIments. There are, however, mdustrial possibilities to upgrade the quality of the sands. Therefore the reserve calculations do not consider the quality of the sands. In regIOn A 8.4 million m3 sand IS available; in region B 51 million m3 sand IS still available. Of this amount 24 million m3 is already under concession and the same amount is present in an area reserved for recreation where exploitation IS probably excluded.

INTRODUCTION

Southern Limburg lies at the boundary between the subsiding North Sea basin and the hercynian uplands of the Eifel and Ardennes (R u t ten, 1969).

During Tertiary time a number of transgressions were alternating with regressions, in such a way that each successive transgression covered an area smaller than the preceding one so that step by step the sea retreated northwards (d e Jon g and van d e r W a a I s, 1971).

The northwest-southeast striking faults (fig. 1) often form the boundaries of the various Tertiary formations.

Tectonically speaking South Limburg has remained rather quiet during the Tertiary till about the end of the Pliocene. At that time the Ardennes and Eifel were uplifted, as was the

I) Rljks Geologlsche DIenst, GeolOgIsch Bureau, Akerstraat 86-88, Heerlen, The Netherlands.

southeastern part of South Limburg. The result of this uplift became noticeable in the Pleisto

cene when large parts of South Limburg were buried under terrace sediments of the river Meuse; part of the Tertiary sediments were eroded by the same river.

STRATIGRAPHY OF THE YOUNGER TERTIARY

The stratigraphy of South Limburg has been compiled in the chart on page 74.

The upper part of the Miocene consisting of fine loamy sands shows a red-yellow paleosol at the top of the sequence in the area north of Heerlen. On the faultblock between the Feldbiss and the Heerlerheide faults sediments of possibly Upper Miocene age are transgressing over the Middle Miocene. Near Hoensbroek the Upper Miocene sediments are found overlying the Frimmersdorf browncoal layers. To the north of Heerlen the Upper Miocene is transgressive over the Morken browncoal.

In the west of South Limburg, at the boundary between the Oligocene and the Miocene the Elsloo layer is present with rounded flintstones, phosphatic nodules and shark teeth (van den B 0 s c h, 1964). In the eastern part of South Limburg only rounded mntpebbles are found; the boundary between the Miocene and Oligocene is less conspicuous here.

REGIONAL DISTRIBUTION OF THE MIOCENE

The map given in fig. 1 depicts the near-surface occurrences of Miocene sediments, omitting the Quaternary. Usually the Miocene is covered by Pleistocene gravels, slope material and loess.

North and occasionally south of the Feldbiss fault, near Sittard and northeast of Heerlen, the Miocene is overlain by Pliocene clastics.

The southern boundary of the Miocene is formed by the Geulle, Kunrade and Heerlerheide faults.

The regional distribution as well as the stratigraphical

74 O.S. KUYL

Time Lithology faCies thickness

PLIOCENE silty clays and humiC clays with browncoallayers flUViatile mtercalated with sands and sometimes gravel to lacustnne max.

70m Quartz gravels with coarse sands and locally

flUViatile clay lenses

UPPER Certam only nor1routh of the Feldblss fme MIOCENE of the Feldblss loamy sands with some

glaucomte, often bioturbate shallow manne max.

MIDDLE developed 120 m

MIOCENE --------------Predommantly white quartz sands alternatmg shallow manne, With brown humiC sands, 2-3 browncoallayers present tidal; 90m Manten (1958) correlated two ligmte layers browncoal With Morken and Fnmmersdorf m Germany contmental

A few layers with flmt pebbles shallow manne 15-30 m

very fme loamy sands with some glaucomte

LOWER >< >< MIOCENE mlssmg

UPPER only present north of the Feldblss, marine ?

OLIGOCENE glaucomte sands

sandy clays mtercalated with clayey MIDDLE glaucomtlc sands shallow manne;

OLIGOCENE At the basal part ellipSOidal flmt pebbles, max.

clay with many cerith!en, thm ligmte layers tidal 55 m

and humus lammae

LOWER At the top often a paleosol; shallow manne 35 m

OLIGOCENE very fme sands with little glaucomte

StratigraphICal table of the Younger Tertiary m South Limburg

* The threefold subdivIsion of the Miocene has flISt been established by our regretted collaborator J.R.J. ten Berge, who passed away m december 1971.

sequence of the Miocene is shown on the five sections (figs. 2-6).

The upper part of the Miocene has not been indicated separately on the sections. The Frimmersdorf and Morken browncoal layers could be lithologically determined on all sections.

THE DISTRIBUTION OF THE PURE QUARTZ SANDS

Up till now the pure white quartz sands have only been exploited in sand pits north of Heerlen on the tectonical block between the Heerlerheide and the Feldbiss faults. The sands must have an Fe203 content ofless than 0.01 % and an Al20 3 content of less than 0.025% in order to be of value for the crystal glass industry. Analyses of these sands have been published in the elvl report (1946). These pure quartz sands have only been encountered below the Morken browncoal layer. The deposits have a thickness of 10-20 m (fig. 7).

Pure white quartz sands might be present in the following areas:

1. Area north of the Feldbiss fault In this region the pure sands below the Morken lignite are for the greater part present under a thick cover of Pliocene and Pleistocene sediments. As shown in fig. 2, section A-A', the thickness of the sediments overlying the Morken browncoal layer is decreasing from about 140 m (borehole 60D-619) to about 25 m measured in borehole 62E-172. Possibilities for an economic exploitation of pure quartz sands appear to be present in Area A (fig. 7), where the sands immmediately underlying the Morken browncoal are close to surface. In four pits north of the Feldbiss fault (east of Brunssum) sands of Upper Miocene age is dug just below the Pliocene gravels. The iron oxide content (Fe2 0 3) of these sands is low, but the regional distribution of the pure sands is very limited. The Fe203 content varies between 0.011 % and 1%.


75

FIg. 1 The occurrence of the MIocene and locatIOn of geologIcal sectIOns.

2. Area between the Heerlerheide and the Feldbiss faults The stratigraphical sequence of the Miocene can be best demonstrated on section B-B' (fig. 3). The thickness of the overburden on top of the Morken browncoal is decreasing from 150 m in the northwest to about 18 m in the southeast (borehole 60D-576). Further to the southeast the Morken layer is sub cropping. Area B on fig. 7 indicates the region where pure quartz sands can be found with an overburden of less than 50 m which is about the economic limit.

3. Area south of the Heerlerheide fault The Miocene sediments south of the Heerlerheide and Benzenrader faults probably belong to the lower part of the Middle Miocene (figs. 4, 5 and 6). There is, however, no palaeontological evidence as yet for their correct age. Besides loess and gravel, Miocene sands are being exploited in several pits in the region between Beek and Nuth south of the Benzenrader fault (fig. 7). These sands contain a large amount of limonite, making them suitable for filling material only. In the same faultblock, further to the northwest, no evidence exists of pure quartz sand of Miocene age. The pure sands have been largely removed by erosion of the river Meuse and replaced by material of the Gronsveld-Caberg terrace (B rue r e n, 1945). On the

~P(ioCene

o 2 3km ! ,.

left bank of the Meuse quartz sands of Miocene age are exploited in Belgium, west of Opgrimbie.

RESERVE CALCULATIONS OF EXPLOITABLE PURE QUARTZ SANDS

The possibilities to exploit pure quartz sand in South Limburg exist at two places:

mH .... P .,>0

·'00

.5O

·'00

,>0

NW

-- - ' -

SECTION A-A'

......-

D H IOCCHE .~POWHCO .. t

D LOWERPARI . Nlot:ENe

76

NW

mN,A,P'

.,00

-50

-100

- 150

s PIT

m N.A.P.

+100

+50

O.S. KUYL

-s

o 2km ',===d.. __ ..,j'

SECTION 6 - 6 1

. - . . ..... .

Oligocene

SE ." ,.,

N

60C 781

01r--------------------~~~--------------~~;t~;;~~~~~;;iJ~~'1:2-~D':~2':J'·~i2iliJL---z .- .. , - .. -.,-.,-

-50

-100

-150

Fig. 4

W ID

o 2km l::=1==d __ ~

SECTION C-C' I Oligocene

m N.A.P. SW

·'00

' 50

0

~1 -1001 -,.oj

-200

Fig. 5

Fig. 7

PURE MIOCENE QUARTZ SANDS IN SOUTHERN LIMBURG. THE NETHERLANDS, STRATIGRAPHICAL OCCURRENCE AND REGIONAL DISTRIBUTION

mN.A.P. +1 00

+ 50

sw 600 305

Oligocene

o 2km b'==d.._.....I'

~I -'I ~I

-50

-100 o 2km

77

NE

600 2,9

SECT ION 0 - 0'

I I I ~- frlmmer$dorf

SECTION E E'

" '(

"\

I Fig. 6

LEGEN D

Location of sandplts and region of potential quartzsand explOitatIOn.

78 O.S. KUYL

Fig. 8 Outcrop near HopeI. A layer of flintpebbles at the top of the lower part of the Miocene.

Fig. 9 Sandplt BeauJean at Heerlerhelde. Morken browncoallayer on top of pure quartz sands.


79

1. To the north of the Feldbiss fault: region A (fig. 7). This area has a size of about 3 km 2 . Within this area the wastedump of the mine Julia is situated as well as the abandoned brown coal pit Anna and the villages of Haanrade and Eygelshoven. The area still available for the exploitation of pure quartz sands is about 0.7 km2 in size. On Dutch territory we do not find any sand pits in this area and only one sand pit, Nievelstein, in Germany close to the Dutch border. Therefore a possibility for the occurrence of pure sands on Dutch territory is still present, but the region is densely populated. Assuming a sand sequence of 12 m thickness, about 8.4 million m3 will be available in region A. Part of the sand will be of high quality.

2. Between the Feldbiss and Heerlerheide faults: region B (fig. 7). The region as indicated on the map has a size of about II km2 . About 7.7 km2 of the area is covered by buildings, brown coal and sand quarries. Furthermore some 1.6 km2 has been put aside for recreational purposes, about 1.6 km2 is already under concession, leaving only 0.2 km2 for future exploitation of sand.

In general the heavy mineral assemblage of the pure quartz sands consists of stable minerals only; in the light mineral fraction the potash-feldspar content is low. This means that the weathering played a considerable role in the genesis of these sands during or after their deposition. Moreover the white sands of high industrial quality are only found when covered by an impermeable covering layer, including lignite (d e Jon g and van de r W a a Is, 1971). This layer is thought to prevent the infiltration of iron-bearing solutions from overlying Pleistocene sediments. The high-quality sands have therefore for the larger part been found below the Morken lignite.

As shown in fig. 3 the Morken lignite disappears towards the southeast, which might well deteriorate the quality of the

quartz sands in this area. However, by washing and milling it is possible to upgrade the quality of the sand. This process is applied by Sigrano Ltd. in the recently obtained concession situated near the former mineshaft of the mine Oranje Nassau IV.

There is reason to assume that the region east of the Heihof fault (fig. 7) has been uplifted and that east of the fault, instead of the pure white quartz sands, only the fine loamy glauconite sands of the lower part of the Middle Miocene occur. These sands are not suitable for use in the glass industry.

If the sands to be exploited are assumed to have a thickness of 15 m the area for future sand exploitation contains about 3 million m3 sand. In the area under concession about 24 million m3 sand is avaliable. The same amount is present in the recreation area.

LITERATURE

Bosch, M. van den (1964) - De stratigrafle van het MIOceen m het OosteltJk Noordzeebekken. Natuurhlst. Maandblad 53 (3), p. 36· 40.

Brueren, J.W.R. (1945) - Het terrassenlandschap van ZUld-LImburg. Med. Geol. Stichtmg, Sene C-VI-l, 93 p.

CIV! Report (1946) - Rapport inzake opsponng, mventansatie en toepassmg van oppervlakte-delfstoffen m Nederland. Med. Geol. StlChtmg, Nw. Serie No.1.

Jong, J.D. de and L. van der Waals (1971) - DeposItIOnal envlTonment and weathenng phenomena of the white Miocene sands of southern LImburg (the Netherlands). Geol. en Mljnb. 50 (3), p.417-424.

Manten, A.A. (1958) - Palynology of the Miocene browncoalmmes at Haanrade (LImburg, the Netherlands). Acta bot. neerl., 7, p. 445-488.

Muller, J.E. (1943) - SedlmentpetrologIe van het Dekgebergte m Limburg. Med. Geol. Stichting, Sene C-II-2, No.2, 78 p.

Rutten, M.G. (1969) - The Geology of Western Europe. ElseVIer PublIshmg Compo Amsterdam, 520 p.

Voorthuijzen, J.H. van (1962) - DIe Obermiozane TransgressIOn 1m Nordseebecken und dIe Tertlar-QuartIar-grenze. Memoires de la SocIete Beige de Geologie. Serie 8, No.6, p. 64-82.


THEGRAVELANDSANDSUPPLYINTHENETHERLANDS

E.OELE 1 )

ABSTRACT

Gravel resources In the Netherlands will be exhausted within a penod of 25 years from now. Sand for Industnal purposes IS present In sufficient quantities for a much longer penod. In order to meet the demand for sand to heighten terrains of future bUilding areas and to make road foundations In the western Netherlands, It appears to be necessary to use In future sea sand In increasing quantities.

1. INTRODUCTION

In the past stones or bricks, the latter as the more commonly used material, were utilized in the Netherlands for building purposes. The change-over to concrete implied a greater demand for gravel and coarse sand, which demand has given rise to supply problems in various densely populated areas in the world. On the one hand the fast growing cities require larger quantities of building material, on the other hand the areas where this material can be exploited become limited for environmental reasons.

In the Netherlands further difficulties arise due to poor soil conditions; large quantities of sand are required to heighten building grounds and to construct foundations for roads. The sand supply for these purposes has already become an awkward problem.

The quantities of the various materials, that were excavated and delivered during the years 1969 and 1970, are presented in table 1. It is a striking fact that the amounts of sand, used for heightening are considerably larger than those for other purposes.

II. GRAVEL

Geological setting

Only one area is of importance for the exploitation of gravel in the Netherlands. About 95 percent of the gravel

I) RIJks Geologlsche Dienst, Spaarne 17, Haarlem, The Netherlands.

TABLE 1 Dehvenes of sand and gravel produced In the Netherlands In mllhons of tons.

1969 1970

Gravel 12.4 14.4

Industnal Sand 19.2 21.2

of which exported 6.2 6.7

Fine sand 44.5 47.5

comes from the province of Limburg, where it is dredged in pits along the river Meuse (fig. 1).

The richest gravel deposits occur in the Central Graben, the main tectonic depression, which runs through the country in a SE-NW direction. Due to an uplift of the hinterland at the end of the Lower Pleistocene the rivers started to transport coarser material into the area under consideration. In the beginning of the Middle Pleistocene the Rhine deposited coarse sands, containing only small amounts of fine gravel. These sands, lithostratigraphic ally known as the Sterksel Formation (Z 0 nne vel d, 1958) are overlain by another sandy series, the Rosmalen Zone. The latter is a mixture of Rhine and Meuse material and as such is a first sign of the influence of the river Meuse in the area. Gradually the river Rhine changed its course and finally the area was fed by the Meuse only, which at that hme transported more and coarser material than before. The coarsest fractions were deposited during the Holsteinian InterglaCial and subsequent Sa ali an Glaciation, the so-called Veghel Formation.

The southward extension of the land-ice mass during the Saalian forced the Rhine to change its course again. As a result the Rhine once more traversed the area, depositing coarse sediments during the Upper Pleistocene, i.e. the Kreftenheye Formation.

During the last glaciation, the Weichselian, the older fluviatile sediments were covered by wind-blown loess deposits, after which period sedimentation came to a standstill.

82 E. OELE

Gravel supply

According to data of the National Bureau of Statistics the quantity of gravel delivered in the year 1970 amounted to 14.4 x 106 tons, which for 95 percent was provided by the Limburg area. This figure is not interesting in itself, but it is of great importance to know for what period the Limburg area can deliver such quantities.

The gravel production has rapidly expanded along the banks of the Meuse during the last thirty years. It is clear that such an expansion required a policy on the part of the authorities. Already seven years ago the provincial government started an investigation into the evaluation- of the quantities of gravel present and the expected demand . Based on this study a programme was initiated to make the most of the effects of the exploitation for the development of the area. The exhausted gravel pits are converted into lakes for water recreation. To this end the deep pits have to be partly filled in with material from the waste dumps of coal mines of the nearby mining area. Fig. 2 shows the situation as it will be after completion of the exploitation and conversion of the gravel pits into lakes.

It has been calculated that the Limburg area could supply gravel for another 30 years, provided that the yearly production would not surpass 14 x 106 tons. Since this figure was nearly reached already in 1970, the exploitation may well have to cease earlier. According to Mr. Raedts (personal communication) it is likely that the pits will be abandoned

LEGENOA

• AREA OF SAND· EXPLOITATION ~ c;;:=='_~ ........ _ FOR I NOUSTR I AL PURPOSES V--

• AREA OF SAND EXPLO ITATION 4> FOR OTHER PURPOSES G/

Ilm!!I AREA OF GRAYEL U EXPLOITATION

Fig. 1

. . . • + · + :++++

+'

"'"Jl ... +~

+ · +

" ... __ ./t .. v. .

Main sites of explOitatIOn of sand and gravelm the Netherlands.

Fig. 2 Planned situatIOn of gravel pitS after completion of the exploitation.

~ GU\lEl PIT TO at; ~[Pl'

~OPEN r-l {iFl'IlV(l PIT TO IE f lUfO(1 l_--1 AFT[A EXPI,.OI AriON

before the deepest gravel beds have been exploited, so that production per surface unit will be smaller than anticipated.

The conclusion can be drawn that within about 25 years from now the gravel deliveries from the Limbrug area will come to a halt. Unfortunately, there is no other gravel-bearing formation known in the Netherlands . The Tertiary sediments consist of fine marine sands and clays, whereas the Pleistocene fluviatile and marine sediments outside the area described here contain only a minor amount of gravel. The Pleistocene glacial deposits too are poor in gravel. The Holocene sediments are predominantly fine-grained; the coarser fluviatile deposits which locally occur contain only small amounts of fine gravel.

Recent investigations of the Dutch area of the North Sea (0 e 1 e, 1971) have confirmed that the North Sea sediments are to be considered as the downstream deposits of the Rhine-Meuse delta, intermingled with mainly fine-grained glacial deposits. Consequently, the Dutch area of the North Sea does not contain gravel deposits. In the southern North Sea along the British coast, gravel deposits occur which have initially been deposited by British Pleistocene rivers. These deposits constitute the British counterpart of the RhineMeuse gravels in Limburg.

In conclusion it can be stated that within some 25 years from now the Netherlands will have to import all the gravel required. It is obviously worthwhile to start an investigation into the possibilities of importing gravel from adjoining areas in Germany and Belgium or from the British area of the North Sea. It should be noted that, in order to satisfy the demand for the London area, large quantities of gravel from the North Sea are already being used. Perhaps after another 25 years it may even no longer be possible to export gravel from these areas .

THE GRAVEL AND SAND SUPPLY IN THE NETHERLANDS 83

III. COARSE SAND FOR INDUSTRIAL PURPOSES

Geological setting

Originally coarse sand was dredged from the great rivers. Already 15 years ago Rijkswaterstaat (Water control & Public Works Department) raised serious objections against this dredging. After negotiations between the authorities and companies concerned and based on a geological investigation an area in the northern part of the province of Limburg was designated as a centre for the exploitation of coarse sand (fig. I).

It has been mentioned above that the gravel is largely found in the Veghe1 Formation, deposited by the river Meuse. Further downstream, in northern Limburg the same formation consists of coarse sands, suitable for industrial purposes. In this area the Veghel Formation is overlain by the Well Sands, an equally coarse-grained deposit of the river Rhine of Saalian age. The sequence is shown on fig. 3.

lkm

Fig. 3 Cross-sectIOn, showmg geologICal situatIOn 111 area of coarse sand explOitatIOn.

The exploitable deposits directly overlie sediments of Pliocene age as the area is east of the Central Graben on a horst, where no deposition took place during the Lower Pleistocene. A series of fine-grained sediments deposited during the Weichselian Glaciation under periglacial conditions overlie the coarse sands.

Supply of coarse sand

The exploitation of the sand has remained below expectations due to the low price of the sand and the high costs of transport. The sand, mainly to be delivered in the industrialized western part of the Netherlands, has to be transported

by ship. Since the area is situated well above the water level of the Meuse, an expensive sluice had to be constructed, thus raising the transport costs of the sand, although the sluice was also necessary in view of the future plans of the area as a centre of water recreation. Moreover, the ships on their way to western Holland have to pass a number of other sluices: time consuming and increasing the costs of transport. Consequently, it appeared to be more economical to import coarse sand via the Rhine from Germany, where it is a secondary product of gravel exploitation, formerly regarded as worthless.

In 1970 Limburg delivered about 13 x 106 tons of which about 6 x 106 tons have been exported via the Meuse into Belgium and even northern France. Some 7 x 106 tons of coarse sand have been imported from Germany.

As a result of the present situation the area around Bergen, northern Limburg, can supply coarse sand in the quantities required for another 40 years.

IV. FINE SAND FOR BUILDING PURPOSES

General

Due to the poor soil conditions and high ground water level in the Netherlands it is necessary to heighten building areas with a sand cover. Since this cover may reach a thickness of several metres it is evident that large quantities of sand are required. For the same reason special techniques have to be used for road building. Normally a channel with a depth of 3 metres or more is cut into the soft peaty and clayey soil. The channel is filleci with sand, on top of which the road is constructed.

The requirements concerning the quality of the sand are rather wide. Despite the fact that even fine sands are still useful for this purpose, the demand can hardly be met. In quite a number of instances a lower quality has to be accepted because of the absence of material of the proper quality in the general area.

Geological setting

In general it can be stated that the sands are of Pleistocene age. In the northeastern part of the Netherlands mainly the cover sands of aeolian origin and the infilling material of tiny river channels, both Young Pleistocene in age, are used. In some instances older sands, deposited prior to the Saalian Glaciation are used.

Fig. 4 shows a cross-section through an area chosen for the digging of sand for the foundation of a road. The pre· sence of boulder clay prevents the exploitation in certain areas. The quality of the sand is poor due to thin intercalations of loam and gyttja. However, no better sites could be found in the neighbourhood.

Also in the area around the cities of 's-Hertogenbosch and Eindhoven, in the province of Noord-Brabant, it is difficult to obtain sands of good quality. The sands, which belong to

84 E. OELE

Fig. 4 Cross-sectIOn of area m the northeastern Netherlands, where fme sands are exploited.

the Twente and Eindhoven Formations, consist of windblown sediments deposited in the periglacial zone during the Weichselian and Saalian Glaciation respectively. Thin layers of loam are present in the sandy series. In many places the situation is even worse due to the occurrence of a loam layer near the surface. This very stiff "Brabant Loam" is assumed to be a deposit of wind-blown fine material in stagnant waters.

In the western part of the Netherlands the quality of the Pleistocene sands is much better (fig. 1). Ice-pushed fluviatile deposits of Middle Pleistocene age are dredged in the I1sselmeer to supply eastern Amsterdam and the adjoining area. Until recently fluviatile Young Pleistocene sands were dredged in one of the estuaries in the southwestern Netherlands, mainly for the Rotterdam area, but this had to be stopped in order to protect the bottom of the estuary against erosion. In the area between the cities of Amsterdam and Rotterdam Pleistocene sands of aeolian and fluviatile origin are dredged in some lakes, for instance in the Vinkeveense Plassen to a depth of over 50 metres, as well as in artificial lakes that originated after removal of the Holocene layers on top of the sand. The Holocene cover, however, may reach a thickness of 8 to 10 metres.

Locally sandy deposits of Holocene age are present. They are Lower Holocene fluviatile bars or channel fills of Young Holocene tidal channels, cut in the older clayey and peaty sediments.

Supply of the sand

Although of lesser quality, sands are available in sufficient amounts to meet the demand for a long period in the northeastern, eastern and southeastern Netherlands. Senous problems may be expected in the western provinces, where about 90% of the total amount of sand delivered is being used. The number of pits in the area between the cities of Amsterdam, Rotterdam and The Hague cannot be increased

unlimitedly. According to a study carried out by Rijkswaterstaat only 15 more pits can be made in this area with a total amount of 200 x 106 tons of sand. It is clear that within a period of 10 to 15 years from now a shortage of sand will arise in the western part of the Netherlands, unless an alternative supply could be found.

Such an alternative supply may be obtained by dredging sand in the North Sea. This has been done already near the I1muiden harbour, where sand has been dredged for use in the western part of Amsterdam.

Fig. 5 Cross-sectIOn of area m North Sea, where young sea sand has been explOited.

As is shown in fig .. 5 only a rather thin top layer has to be removed; already at shallow depths Lower Holocene tidal flat sands are present. However, these sands cannot be used for building purposes. When not covered by coarse Younger Holocene deposits, the sands may easily be eroded by sea currents which might endanger the coast. .

Extensive areas with suitable sand are available in the North Sea. The price of the sand depends largely on transport costs and on the additional expenditure for washing the sand to decrease its salinity. The closer to shore the sand can be dredged the lower the price of transport will be. Therefore, it is recommended to start an investigation in order to establish the shortest distance from shore at which sand can be dredged without the risk of damaging the coastal dunes.

REFERENCES

Maandstatlstlek voor de Bouwnijverheld (1971) - Nr. 12. Oele, E. (1971) - The Quaternary geology of the southern area of the

Dutch part of the North Sea. Geol. & Mljnb., Vol. 50, p. 561-574.

ProvmcJe Limburg (1969) - Toelichtmg structuurVlSle voor het gnndwmmngsgebled m Limburg.

RIJks Geologlsche Dienst (1948) - Zand en Gnnd Rapport, Rapport 69. (1966) - Gnndonderzoek Beegden, Rapport 464.

RIJkswaterstaat (1967) - Noordzeezand, noodzaak en mogelijkheden tot de Ultbreldmg van wmmng van Noordzeezand voor het westen des lands. Rapport Werkgroep Noordzeezand.

Zonneveld, J.I.S. (1958) - Lltho-stratlgraflsche eenheden m het Nederlandse Plelstoceen. Med. Geol. Stlchl. N.S., Vol. 12, p. 31-64.


PEAT DEPOSITS AND THE ACTIVE CARBON INDUSTRY IN THE NETHERLANDS

W.H. ZAGWIJN & H.M. HARSVELDT 1)

ABSTRACT

RaIsed bogs of Holocene age are found In the eastern part of the Netherlands and consIst of two superImposed types of Sphagnum peat. The older Sphagnum peat has a black-brown colour and IS strongly humifJed; the younger Sphagnum peat has a lIght-brown colour wIth lIttle humifIed materIal and is loosely textured.

In the manufacture of actIve carbon only the older Sphagnum peat IS used. After an extensIve drying process the peat IS carbonIzed In

large rotary kIlns. The absorption quality is a functIOn of temperature and gas concentratIOn.

The Netherlands export about 75% of theu productIon and IS the second largest producer in the world.

A. THE ORIGIN AND NATURE OF PEAT DEPOSITS

Extensive peat-formation took place in The Netherlands during the last 10,000 years, the Holocene. Climatic conditions were temperate and moist and highly favourable for peat accumulation, both in low moors as well as in raised bogs. The name raised bog derives from the observations that the surface of these moors is curved well above the surroundings, which is caused by the fact that their plant communities can grow independently of the ground water table, the necessary water supply being derived directly from rainfall. In such an environment mineral nutrients are rare and oligotrophic conditions previal. Especially Sphagnum, a genus of mosses which by the sponge-like texture of their tissue are adapted to retain excess of water, contributes to the peat accumulation in the raised bogs. The kind of peat formed in this environment is characterized by a very low ash content, generally less than 1 %, in contrast to the peat formed in low moors, where supply both of mineral nutrients and of clastic sediment result in much higher values of ash content, even up to 90% (V 0 n P 0 stand G ran I u n d, 1926).

1) Netherlands GeologIcal Survey, Spaarne 17, Haarlem.

In the raised bogs of the Eastern Netherlands, like elsewhere in NW Europe, two superimposed types of Sphagnum peat can be found. The lower one is strongly humified, blackbrown in colour, showing little texture and drying irreversibly, which means that once dried, it does not take water anymore. This is the Older Sphagnum peat (Dutch: Zwartveen, German: Schwarztorf). Overlying this is the Younger Sphagnum peat (Dutch: Bolsterveen, German: Weisztorf), consisting of little humified material, lightbrown in colour, of loose texture, as the original plant tissue is only partly decomposed. This peat, after drying, can re-absorb its original water content, a property in common with the living Sphagnum moss cushion. Often it looks as if the contact between the two kinds of peat is sharp. It is known as the "Grenzhorizont". In other cases a transitional type of peat is present.

As to the causes which have led to this differentiation in humification, little is known with certainty. On the one hand it is known now, that often repetitions are present, which means that several Grenzhorizons occur on top of each other. On the other hand it has been found, that a Grenzhorizon when followed laterally even within one peat bog c;an be of quite different age (Van Z e i s t, 1955; S c h nee k lot h, 1965). Probably a complicated process of climatic change (both temperature and precipitation) in combination with the local hydrological conditions in the peat bogs have been involved (C asp a r i e, 1969). The general well known picture of highly decomposed below little decomposed Sphagnum peat is extremely striking. It may reflect the overall decline in temperature from the middle of the Holocene towards present times.

Large parts of the surface of The Netherlands have been covered by peat in the Holocene. About 75% of its surface is (or rather was) covered by Holocene deposits. Originally about 14% (by volume) of the Holocene deposits consisted of peat (Van S t r a ate n, 1963). Now only in the low lying western part of the country extensive peat accumulations can be found. Greatest part of the former raised bogs in the east has been dug away by man.

Peat digging in this country is known since about the

86 W.H. ZAGWIJN & H.M. HARSVELDT

twelfth to thirteenth century A.D. As wood was scarce, peat was used increasingly as a fuel, especially since the large and systematic excavation of the raised bogs of Drenthe, Friesland and Groningen began about the end of the 16th century. Peat digging for fuel reached its culmination after the middle of the 19th century, but has lost its economic importance since the last 50 years, and is hardly carried out anywhere.

From about 1700 large areas of the raised bog surfaces of the Northern Netherlands and adjoining regions of Northwestern Germany were used in the cultivation of buckweat. In this type of culture the peat surface is tilled and burnt and buckweat is sown in. During five years a harvest is possible, after which a period of rest of some 25 years is required. Until, in the beginning of this century, this type of cultivation was forbidden, nearly all raised bogs of the area underwent one to several phases of burning. In the middle of the 19th century it is reported that 20% of the entire "raised bog" surface of the Netherlands was in flower with buckweat, the remainder by lymg fallow (V e n e m a, 1855). In this process much of the upper part of the Sphagnum peat, mainly consIsting of younger Sphagnum peat, was lost. During each campaign of burning and subsequent rest of say about 30 years up to more than 30 cm of peat was lost. In some areas, like southeast Drenthe, more than 1 m of peat had disappeared by burning for buckweat cultivation, before the final digging of fuel began.

Besides for the making of active carbon, which will be dealt with below, at present peat is dug for the making of peat litter, for the production of which only the little humified younger Sphagnum peat is suitable. It is used for agricultural purposes (improvement of heavy clayey soils) and in gardening.

B. THE EXPLOITATION OF PEAT IN THE MANUF ACTURE OF ACTIVE CARBON

Active or activated carbon is a form of manufactured porous "coal" with an extremely high adsorption capacity. It is prepared by heating organic material, e.g. wood or peat and for specific purposes coconutshells, to a high temperature of 900 to 1,000° centigrade.

1. History and development of the active carbon industry

In the Netherlands, active carbon was first used to purify and decolorise pressed sugar juice from the filter dirt in cane sugar refining. The active carbon was supplied by the Hollandsche Fabriek van Wasproducten founded in 1910 in Amsterdam. Initially the active carbon was obtained from central Europe but during World War I supplies became unavailable necessitating an alternative source of supply and domestic production.

At first the woodleavings from a sawmill at Zaandam were used as a raw material in a factory situated also in Zaandam.

However, with the scarcity of wood during the war, further experiments were undertaken with peat. Peat obtained from the province of Drenthe was of a satisfactory quality and cheap, thus supplies of peat from Drenthe were shipped to the factory.

Further uses were discovered for active carbon in the refining of oils and fats, the purification of drinking water, the decolorisation of glycerine and glucose juices and the decolorisation of various products in the chemical and

pharmaceutical industries. A rapidly developing market for active carbon was found

in the United States and United kingdom and the profitable sales potential of the active carbon industry attracted the N.V. Purit Maatschappij, founded in 1921 who owned vast fen-lands in the Netherlands. In 1924, Norit amalgamated with N.V. Purit Maatschappij, Norit buying the capital stock of Purit which became a purely production company. Affiliated companies were established abroad but these ended at the beginning of World War II. Norit still retains a factory in Scotland which manufactures active carbon from woodleavings and sawdust.

2. Concession regulations on exploitation of peat deposits

In 1948, Purit began exploitin(T peat in the Amsterdamsche Veld and the Schoonebekerveld within the munici-

J:jRICA

~VEENDERIJ ~ NV PURIT MIJ

Fig. 1

KLAZ I E NAVEEN

I

MIJ

+ + + + +

2km

PEAT DEPOSITS AND THE ACTIVE CARBON INDUSTRY IN THE NETHERLANDS 87

palities of Emmen and Schoonebeek. The Purit concession areas comprise some 1,400 hectares of which about 330 hectares is company property, the remainder having been obtained from the government or from third parties. Concession and peat-digging rights are valid for a period of 25 to 30 years.

The Mining Law of 1810, Article 3, describes peat as a mineral resource, the exploitation whereof establishes a "miniere". The Mining Law of 1895 disposes of the decrees with regard to the exploitation of peat and introduces a peat-digging law. The Mining Law of 1965, Article 32 has withdrawn this peat-digging law and imposes rules with regard to tillage, ("Ontgrondingswet").

In compliance with this law, permission for 'ohe exploitation of peat is given by the County Alderman of the province concerned. An application for the exploitation of peat is considered by the County Alderman, who establishes the rules of tillage after consultation with interested parties and experts and will grant, alter or refuse permission within three months of submitting the application.

3. The processing of peat in the manufacure of active carbon

The conversion from peat to active carbon is undertaken in the following stages.

The upper, younger Sphagnum peat and the peat at the Grenzhorizon (about 170 cm deep) is removed and the peat mould sold for agricultural purposes. The area containing the lower, older Sphagnum peat (some 150 cm deep) is levelled and drained. The older Sphagnum peat is removed, mixed, partially compressed and spread out on the field in 30 metre strands by excavators. These strands are cut into "turf' lengths by a cutter attached to the excavator. Each year an excavator makes two "round trips" along a continuously broadening peat pit cutting and removing some 3 to 3.40 metres width of peat from both sides of the pit. Each pit is 150 metres apart and may be several kilometres in length. Some 100 hectares of peat are excavated annually, taking some 25 years to strip an area of its peat. However, due to a gradual decrease in peat digging in the Netherlands and the continuous need for raw material alternative supplies are being obtained from adjacent peat diggings in western Germany which account for 60 hectares of the above annual production. The peat is left in the field to dry in the sun and wind as initially 100 parts of dry material contain some 900 parts of water. The peat required for thermal processing is not allowed to contain more than 45 parts of water. In the peatery about 500 million litres of water are removed annually by nature. After a few weeks, the outer layer of the peat hardens at which stage it may be referred to as "turf'. To hasten this natural drying process the turf is stacked in little piles, (Scots - stooked; Dutch -opstoeken), which are later turned, (Dutch - omstoeken). After six to ten weeks, the dried stacks of peat are

brought into a drying field, (Dutch - zetveld) and the process of stacking and turning is repeated. After a further period of six months to a year, the peat is transported to the factory at Klazienaveen and stored in drying rooms. The thermal treatment of the dried peat is a carbonisation process which is undertaken in large rotary kilns 36 metres high and 4.5 metres in diameter. In these kilns, the peat is subjected to a controlled reaction with water vapour and carbon dioxide at a high temperature to obtain the desired degree of activation. The temperature control and gas concentration determine the development and size of the pores (porosity) and the nature of their internal surface (microporosity). The adsorption qualities of active carbon are a result of porosity caused by the unbounded, molecular carbon crystal complexes. The number and size of these pores determines the quantity and speed by which the matter to be adsorbed is transported to the internal surface. The micro porosity of the internal surface is a result of a chemical reaction between the carbon of the dried peat and the water vapour, which produces carbon monoxide &nd hydrogen. These gases in escaping through the material expand and widen the original small crevices providing a microporosity which increases the internal surface area. The porosity and micro porosity of active carbon can be measured from adsorption isotherms obtained with benzene or nitrogen at low temperatures, which reflect the connection between the change of active carbon and the concentration of the material adsorbed. Large pores are measured by means of mercury penetration. In the initial carbonisation of the peat about 65% of the original substance is removed. In the following activation a further 60 to 70% of the remaining carbonised material is removed. In the manufacture of a high quality active carbon only 10 to 14% of the original weight of the dry peat remains. In the manufacture of powdered active carbon, the activated product as it comes from kilns passes through one or more rotating mills which grind the irregular lumps to the required fineness. However, in the manufacture of granul;tr active carbon, the raw material (dried peat) is finely ground and mixed with a binding agent. This mixture is passed through moulds forming strands which are dried, carboni sed and activated resulting in the production of cylindrical, hard grains with a diameter of 0.8 to 0.4 mm and a length of 3 to 8 mm. For chemical and pharmaceutical uses the inorganic components of active carbon are undesirable and are removed by treatment with diluted acids in a continuous washing process resulting in an active carbon with a high degree of purity.

4. Uses of active carbon

The most important uses of active carbon are: the decolorisation and purification of sugar and glucose juices

88 W.H. ZAGWIJN & H.M. HARSVELDT

and in chemical and pharmaceutical products; the purification of vegetable oils, animal oils and fats, polluted organic solvents, polluted air, sewage water and the adsorption of toxic gasses; the improvement of taste and odour of alcohol, drinking water, distilled water from seawater; the purification and separation of gases; the recapture of volatile solvents; catalytic and medicinal.

5. World production of active carbon

The world production of active carbon amounts to about 250,000 tons per annum. The Netherlands exporting about 75% of their production is the second highest producer of active carbon (25,000 to 30,000 tons per annum) preceded by the U.S.A. and followed by Japan, West Germany, France and U.K.

ACKNOWLEDGEMENT

Thanks are extended to the Management of the N.V. Algemene Norit Maatschappij, Amsterdam, for advice and

support received in preparing the technical part of this article.

LITERATURE

Casparie, W.A. (1969) - Bult- und SchlenkenbJidung im Hochmoortorf. VegetatlO - Vol. 19, p. 146-180.

Post, L. von & E. Granlund (1926) - Sodra Svenges torvtillgangar. I. Sver. Geol. Unders. Arsbok 19, No.2 (1925).

Schneekloth, H. (1965) - DIe Rekurrenztlache 1m Groszen Moor bel GIlliom - eme zeltglelche BIldung? Geol. Jhrb., Vol. 83, p. 477-496.

Straaten, L.M.J.U. van (1963) - Aspects of Holocene sedImentatIOn m The Netherlands. Verh. Kon. Ned. Geol. Mijnb. Gen., G.S. Vol. 21-1, p. 149-172.

Venema, G.A. (1855) - De Hooge Veenen en het Veenbranden. Landbouwboekje, Haarlem, 46 p.

Zelst, W. van (1954) - A contnbutlOn to the problem of the so-called Grenzhonzont. Palaeohistoria, Vol. 3, p. 220-224.


THE LAW AND MANAGEMENT OF GROUND-WATER RESOURCES

G.W. PUTT0 1)

When the Royal Netherlands Geological and Mining Society was founded in 1912, it would have been impossible to discuss ground-water problems adequately. Hydrogeology was still in its infancy and in view of the limited knowledge at this time fact was substituted by speculation in many cases. The legal consequence of this situation was given expression in a British court decision which stated: "The source and flow of these waters are so unknown that it is impossible to formulate any legal rules governing them".

Fortunately the science of hydrogeology advanced with the increase of the need for water. The subject of ground water appeared more frequently in courts of law due to disputes between owners of contiguous lands. As long as the law did not provide that ground-water management was a governmental task these disputes had to be settled by means of civil law. The rules of civil law differed according to the availability of water in the regions where the matter was brought before court. Es~ecially in the U.S.A., where so many different climatological and hydrological conditions exist, quite a diversity of water law rules arose from the court decisions.

In the eastern United States, where water is abundant, no restriction was applied to the abstraction of ground water even if water of a well on neighbouring lands would be intercepted or drained. Elsewhere, less favourable hydrological circumstances led to the rule of "reasonable use" stating that a man's right to use water on his own land is limited by the corresponding rights of his neighbour and restricting each to a reasonable exercise of his own right, a reasonable use of his property.

Where water was still scarcer the so-called California rule of "correlative rights" came into force. This rule stipulates that disputes are to be settled by giving to each a "just and fair" portion. In the very arid parts of the U.S.A., however, there was not even enough water to satisfy partially the

1) Deputy-DIrector of the RID (Government Institute for Dnnkmg Water Supply), Parkweg l3, The Hague, The Netherlands.

needs of all concerned. Here arose the gold miners rule, the doctrine of prior appropriation which provides that the first man who occupies an available source of water becomes the legal owner.

In the Netherlands the first court decision in this field was pronounced in 1944. The decision of the High Court of Justice corresponds with the above-mentioned rule of "reasonable use". In this case two landowners brought an action against the Municipality of The Hague because its pumping station abstracted water from their lands, causing damage to the vegetation. The Court declared this form of abstracting ground-water to be illegal and a violation of the law of property.

Not only civil law but also the Act of 1875 on installations which may cause danger, damage or nuisance was an infringement of ground-water withdrawal. The Crown, acting as an administrative court of appeal with regard to the enforcement of this act, had decided that the use of pumping engines may not be authorized if it could be expected that pumping would cause damage to neighbouring grounds.

The obstacles to ground-water withdrawal under private and public law led to the Water Undertakings GroundWater Act. This act requires a licence for the withdrawal of ground water by wat~r undertakers which may be granted even if this would cause damage to others. In this case, however, there must be a sound reason that the supply of drinking water should prevail. Further, the water undertakers have to compensate the damage they cause. This act only deals with ground-water withdrawal for drinking water purposes and thus only partIy regulates ground-water management.

The world-wide rapid increase in the demand for water is observed in the Netherlands as well, and is due to the population growth, the increase in the daily per capita domestic consumption and to the continuously growing needs of industry. The demand for water in the year 2000 has been estimated at 4,500 million cU.m. per annum, while the available amount of ground water is estimated at only 1,900 million cU.m. The present use of ground-water

90 G.W.PUTTO

amounts to 1,200 million cU.m. per annum. In view of this critical situation and considering the

serious problems involved with the unavoidable utilization of surface water the Government Institute for Drinking Water Supply was requested to prepare a masterplan for future water supplies. The situation requires a ground-water resources policy under the auspices of the State. The following points should be taken into account. 1. An inventory of the available amount of ground water

and its geographical distribution should be prepared. Cooperation between the appropriate governmental services and independent institutions equipped for groundwater investigations should be further stimulated.

2. The amount of ground water withdrawn should be registered. In most provinces this obligation has been promulgated by the provincial governments. It will be enacted in the ground-water legislation which is now being prepared.

3. The withdrawal of ground water should be licensed by the authority as designated by Act of Parliament, taking all interests concerned into consideration. In the first place there are the interests of the Water Supplies and industries, which may be conflicting when the available supply of water is not sufficient. Also the interests of various sections of society which may be injured by the lowering of the ground-water table have to be taken into account, such as agriculture, forestry, environmental conservation, buildings which may be damaged by setting of the soil and the possible increase in the salinity of water. A decision should always be in harmony with the public

interest, but it cannot be denied that in many cases it will be difficult to determine what the public interest requires. Therefore a decision should be preceded by consultion with experts and a hearing of interested parties.

4. It has been rightly said that we are living on the roof of our cistern. Therefore the protection of ground water is a necessity, be it for human consumption or for other purposes. Ground water may be polluted bacteriologically and chemically by domestic and industrial waste. Other harmful pollutants are oil products such as petrol and paraffin, which can make water unfit for use for a period of many years. The usual method of groundwater protection is to designate special areas where many activities are prohibited and only some are admitted under certain limitations. In the first instance the catchment areas used by the various water undertakings have to be protected. Some forms of pollution have to be prohibited in the whole of the country, unless authorized by special licence, e.g. the discharge of waste products into the subsoil by means of boreholes. In the Netherlands protected areas were designated within the framework of town and country planning. In that way the building and the execution of works such as roads, camp-sites and parking-places may be restricted and controlled. Complementary provisions were in many cases promulgated by provincial ordinances. A national legislation dealing with the protection of soil and ground-water is now being prepared.


DEVELOPMENT OF GROUND-WATER RESOURCES IN THE NETHERLANDS

E. ROMIJN 1 )

SAMENV ATTING

In dIt artlkel wordt een overzlcht gegeven van de studies die tot nu toe werden verncht m verband met de bepalmg van de mogeliJke grondwaterwmnmg m Nederland. De conc1usies zijn als voorlopig te beschouwen, daar een aantal studies nog met is vol to Old en daar over de gevolgen van de grondwaterwmning nog geen eenstemmtg oordeel heerst.

1. INTRODUCTION

In a previous article on the geohydrological research in the Netherlands the possible production of fresh ground water in the Netherlands was estimated at 1.9 X 109 m3

per year (R 0 m i j n, 1972). This estimate was based on the results of a number of regional investigations which had been carried out mainly by hydrologists of the RID, namely by 1.H. Beltman (province of Limburg), 1. Blom (province of Drente), M.C. Brandes (Alblasserwaard), 1.M.G. van Damme (province of Utrecht), K.G. Lamsvelt (provinces of Noord-Brabant, Overijssel), K. Meinardi (province of Gelderiand), E. Romijn (province of Gelderland), W. Visscher (province of Noord-Brabant) and H.G. van Waegeningh (province of Drente). These studies were either made at the request of the water undertakings or in behalf of the masterplan for the future water supply of the Netherlands. Some studies by other institutes will be mentioned in the text.

II. SHORT HISTORICAL REVIEW

At the beginning of this century the regional geohydrological research related to the supply of drinking water had already started. The object of this research was to estimate how much ground water could be abstracted in a certain area. Around the turn of the century the Dune-

1) RID (Government Institute for Dnnking Water Supply), Parkweg 13, The Hague, The Netherlands.

water Company at Leiduin, which was founded in 1853 and supplied Amsterdam with water, got into trouble because of exhaustion of the catchment area. The Municipality of Amsterdam looked for new sources. There was the plan Pennink (1901) which suggested irrigation of the dunes with water from the Rhine taken in at Schoonhoven. In 1902 it was proposed to pump ground water from the Veluwe, while some years later investigation wells were drilled in the "Gelderse Vallei" by the Municipality of Amsterdam. After 1910 the impulse to the development of water resources was given by the foundation of regional water undertakings, at first in the southwest and west of the country. The Government gave advice and support, amongst others by setting up the Central Committee for Drinking water Supply in 1913 and the State Office for Drinking water Supply (later the RID) and by giving risk guarantees. Many studies have been carried out in this connection: the report "Friesland" (RID, 1919a) and the report "CDV" (RID, 1919b) can serve as examples. In these reports a planning over 30 years was chosen after an investigation of the optimization of costs of construction and the interest of the pipelines. Thus a prognosis for the year 1950 was made. In the report "Friesland" the domestic consumption for the year 1950 was estimated at 40 litres per head per day (l/h.d), which in fact turned out to be 941/h.d.

In the urbanized western part of the Netherlands with its continuously expanding population the consumption per head also increased as well as the supply of drinking water to the industry (C e n t r a I e Com m iss i e, 1940). In this report a prognosis of 12 million inhabitants for the whole of the Netherlands in the year 2000 was given, of which 6 million would live in the west. For the year 2000 the demand for drinking water in the west was estimated at 385 X 106 m3 • How these figures have been overtaken by events is shown in table 1. In recent literature (Z u ide m a, 1970) the population of the Netherlands in the year 2000 is estimated at 17.9 million inhabitants, and the demand for drinking water of population and industry at 4.5 to 5.5 X 109 m3 .

The explosive development after 1945 led to a revision of

92 E. ROMIJN

TABLE 1

Increase m the consumptIOn of dnnkmg water m the Netherlands.

YEAR

PopulatIOn on 1st January

ProductIOn water undertakmgs

1840

2.9 X 106

1940

8.8 X 106

230 X 106

1950

10.0 X 106

319 X 106

1960

11.4 X 106

504 X 106

1970

13.0 X 106

872 X 106

the report "Westen des Lands" (C e n t r ale Com m i s -s i e, 1940). The new report (C e n t r ale Com m iss i e, 1967) estimated the possible production of fresh ground water at 1.5 X 109 m3 per year. Earlier the same figure had been mentioned by B.A. van N e s (1965). It had been calculated in the following way. The 23,000 km2 of high grounds in the Netherlands had been multiplied by a mean of precipitation minus evapotranspiration of 200 mm per year, which gives a total of 4.5 X 109 m3 per year. It was assumed that about one third could be withdrawn, that is to say 1.5 X 109 m3 per year. This would mean a doubling of the ground-water production of 750 X 106 by water undertakings and industry in 1964. Comparing this figure with the above-mentioned demand for drinking water, it becomes evident that it is of prime importance that an inventory should be made of the available ground water, as the costs of production from surface-water sources will continue to grow because of the increasing pollution. A survey of the water production in 1967 is given below, 1967 being the year in which the C.B.S. (Central Bureau of Statistics) held an inquiry on this subject (table 2).

III. GEOLOGICAL AND HYDROLOGICAL ASPECTS OF THE GROUND-WATER ABSTRACTION

a. Hydrogeology and hydrochemistry

Regarding the geology of the Netherlands the reader is referred to the Transactions of the KNGMG (1963). Recently a number of hydrogeological maps were published (J e 1 g e r sma and Vis s e r, 1972). It should be mentioned here that in the Netherlands fresh ground water is mainly obtained from Pleistocene deposits. In the lower part of the Netherlands however these deposits have become salty except, for instance, below the dunes (fig. 4). In the east, southeast and southwest of the Netherlands water is also obtained from pre-Quaternary deposits.

As the ground water in the Netherlands usually flows slowly, for instance some tenths of metres per year, one may presume that with regard to its chemical and biological aspects the ground water will be in balance with its surroundings (Schoeller, 1956; Lips et al., 1969; B r i e f van deS t a a t sse c ret a r i s, 1969). If one follows the cycle: precipitation, infiltration into the soil, percolation and ground-water flow, seepage, river discharge,

TABLE 2 WaJer 3balance for the drmking- and industry-water supply m 1967 m 10m (C.B.S.).

Abstraction ConsumptIOn

1. fresh ground water 1. domestic (U81/h.d.) by waterworks 496 2. mdustry by mdustry 427 a. delivered by Imported 3 waterworks

2. brackish and salt b. pnvate productIOn ground water by - process water* mdustry (mamly - cooling water** cooling water) 46

3. artifiCial recharge by waterworks 105

4. surface water by water works 156 by mdustry 2086

Total abstraction 3319 Total consumptIOn

* process water = ground water 195, surface water 190. **cooling water = ground water 275, surface water 1896,

except cooling water power plants (= 5.6 x 109 m3).

538

225

385 2171

3319

sea (evaporation ...... precipitation), amongst other things the following chemical phenomena take place.

Precipitation. Near the Dutch coast Cl- values up to 22 mg/l have been measured in the precipitation, and in the centre of the Netherlands up to 3 to 4 mg/l only. Non-polluted rainwater contains about 0.5 mg/l of CO2 which is in balance with the atmosphere.

Infiltration, percolation. While the precipitation infiltrates into the soil oxidization and hydratation (weathering) take place and directly connected with this also biochemical weathering. Through respiration and desintegration of organic matter CO2 can reach values up to 500mg/l (S c hoe 11 e r, 1956). The lithosphere is for 99.34 weight percent composed of 0, Si, AI, H, Na, Ca, Fe, Mg, K, Ti, (in sequence of atom percentage), while another 0.41 weight percent is composed of Mn, P, F, S, C and Cl. During the weathering process Si02 is very resistant, while the sesquioxides (AI, Fe) dependent on the PH dissolve. Aluminium (Al) dissolves mainly at a PH less than 4.5 or more than 8.5. For the ferro-ion (Fe ++) in balance with Fe(OHh holds that the concentration of Fe ++ diminishes with an increase in the oxygen content and with an increase in the PH of the solution. Fe +++ precipitates in H2 0. In the temperate zone

DEVELOPMENT OF GROUND-WATER RESOURCES IN THE NETHERLANDS 93

clay minerals originate from the dissolved Si, Al and Fe-ions. In the tropical zone resistant sesquioxides can form bauxite or laterite (W est e r vel d, 1951). Alkaline earth metals are mainly dissolved as a hydrogencarbonate under the influence of CO2 pressure; alkalies remain dissolved be it that especially K is adsorbed to clayminerals.

Through the flow of ground water the dissolved minerals reach the surface water. The colloidal particles in the river water (clayminerals, iron-humus compounds, etc.) precipitate near the sea due to an increasing percentage of electrolytes. For the composition of sea water see table 3.

Other important hydrochemical aspects are:

1. Biochemical phenomena. - To a large extent these are determined by the PH and the redox potential of the environment. Organic acids and decay matter, and afterwards H20 and CO2 are formed by the diSintegration of assimilation products. Trace elements (such as B, Cu, Mn) which had been withdrawn from the soil by the vegetation, nitrates, sulfates, phosphates, alkalies and alkaline earth metals are liberated. Due to the consumption of oxygen by bacteria and

TABLE 3 Water quality

- :; no d a t a t = t r Cl ce

LOCATION

date number

ground level (m)

filter depth em)

FRESH GROUND-WATER FROM SANDLAYERS

ZANDVOORT

17-7 -'S3

24F-34

+ 12,3

34-36

BAREN -DRECHT

8- 3 - 68

37 H-271

NAP

35,7 -47,5

APElDOORN SUSTEREN RU! NERWOLD

28-8-66 19-3-65 15-1-63

33B -164 60A-193 16H -24

+30 +31,5 +2,5

49,2 -97,2 109,7-122,9 38,8-57,2

fungi for mineralization the environment can become anaerobic. As a result Fe ++ and Mn ++ can dissolve (also colloidal by humus acids), while H2 S, NH4 + or CH4 can be formed. Inversely the bacteria oxidize NH4.+ (nitrification), H2 S, Fe ++

and Mn++. The N03 - and SO; can disappear from the water by resp. denitrificating bacteria (-+ N 2 t) and by sulfate reducing bacteria (-+H2 St), while nitrogen binding bacteria can convert N2 from the atmosphere into N03 -. Finally ground water can be polluted by human action (fertilizers, domestic salt, oilproducts, etc.).

2. Long reSidence time of ground water below surface. Stagnant ground water or ground water flowing deeper into the soil can still undergo a change in composition under the influence of temperature (the solubility of salt often increases, but that of gas instead decreases with increasing temperature), pressure (solubility of gas increases with higher pressure), contamination (mixing or diffusion, influence of other ground water, oil, gas, juvenile components) and time of contact between soil and water through which the amount of salt can increase from 1 to 20 g NaCI/I (S c hoe II e r,

SALT GROUND·WATER

GRQEDE

20-12-51

4S C - 27

NAP

15 - 16

HEERLEN

1956

° N [ - 133 a

+120

250

WORLD MEAN

RIVER-WATER

RH INE ("pure" )

± 1875

RHI NE (RHENEN)

1928 - 31

(P04 '932t38)

SEA

STANDARD

remarks Ee:m f Kedlchem f Fluv 8runssum t Enschede- Holocene Carboni_

fero us

FWCarke

(1924)

USGeolS

no 770

E L Molt

(1961)

TH Delft

(1: formation)

cOlor{mg Ptl

cond ().IS Icm)

suspended lOad

pH

KMn04 demand

CI

NO,

NO,

S0,

H C0 3

CO,

PO,

51 ° 2

H,5

sum m val/I(Olo)

NH, organic NH4

F,

"0 Co

"9 No

m va III (ala)

alKolln (No HCO l )

O 2 (sat a/a)

°0 (toto I)

°0 (HC0 3 )

J(gammo)

ot hers

Pie Istocene HarderwlJ"- f

(preglac) sand

lime rich

clayey

peat

Lime rich lime less Lime less LI me less

quartz -

sand

Lime rich sandstone

clayey (some pe:at) clayey humuous (1956=40 0 C)

peat humuous (19S0= 50°C)

mg/l mvol/l mg/l mval/I mgll mvolll mgtl mval/l mg/l mvol/I mg /1 m va III mg/l mvol/I

15

424

7,84

'"

20

1090

7,41

33

98

<6,5

17

100

7,02

11

335

7,33

12

270,76(7,2) 732,06(7,2) 14 0,40(15,8 9 0,2519,5) ,4 0,39(4,1)155004362(4153)24800698,6(4815

o 0 0

12,2 0,25(2,3} 8,0 0,17(0,6) 10,3 0,21(8,2) 1,0 0,02(0.8) 6,S 0,14(1,5) 50,3 1,1 (0,1) 624

262 4,30(40,5) 729 11,95{42,1 40 0,66(26,0 64 1,05(39,7) 256 4,20(44,2) 2700 44,3(4,6) 519

13,0 (0,9)

8,5 (D,6)

47 27

1,02 0,03(O,1} 0,07

42,4

5,31 (50)

1,4 0,08 (O,B) 1,2

0,17 0,40

1,9 315

0,29 0,12

12,0

14,21{50l

0,07(0,3 0,07

0,06

0,03

1,27 (50)

1S

0,04

1,32 (50)

29 95,3

0,64 0,0210,2) 31,8

84

4,75(50)

0,14 OO,HO,4) 0,53 0,03(0,3) 8,8

2,9

0,13

5,8

0,10 0,19

1,S

2.4

2,57

481,6(50) 720,1(50)

O,S(O,l} 50 2.8

80,04,00(37,6) 152,0 7.60(26,8 10,6 0,53(20,9) 15,8 0,79(30,1) 68,0 3,40(35,1 299 15,111,5) 1852 92,S{6,4)

4,8 0,40(3,8) 22,6 1,88(S,6) 1,6 0,13(5,1) 3,7 0,31(11,8) 7,2 0,60(6,2106088,2(9,1) 336 27,5(1,9)

19,00,83(7,8) 103 4,48(15,8) 14 0,61(240} 4,6 0,20(7,7) 18,7 O,Bl(S,4) B610 3744ll85) 360759110(407)

6 0,15(0,5) 315 S,1{D,B) 573 147(1,0)

5,31 (50) 14,18(50) 1,27{SO)

207

12,3 4,40 26,5 9,4B 1,8 0,66 3,1

12,0 4,30 26,5 9,48 1,B 0,66 2,9

1,31 (50) 4,B4 (50) 4B6,3{5Q) 729,2(50)

1,10 11,2 4,00 2B9 103,3 33S,3 120,1

1,05 11,2 4,00 12,4 4,6 23,7 8,5

1,27

Br= 32 mg/l (CH",C0 2 ,N 2

He, A r)

mg/l mvolll

(e,O)

(0,7)

(12,6)

(289)

(50)

mgtl

10

10

mval/I mgt! mvol/ I

22

449

34,1

7,S7

20,3

H U Sverdrup

(1949)

The oceans ----chloroslty

mg/l mvol/l

(8)

12 0,34(4,6) 62,S 1,77(16,3)18980~34,7("!51)

0,118 t

0,03(0,4) 3,2 0,05(0,5 <0,7

35 a,73 (9,8) 45,2 0,94{S,7) 2649 55,1 (4,7)

160 2,62(35,Z 163 2,67(24,5) 140 2,3 (D,2)

5.2

0,125

7.7 0,01-7

3,72(50) 5,43(50) 592,1(50)

0,32 0,02 (0,2) t

0,15 0,01 (0,1)

(2,1) 0,2 0,35 0,01 (0,1)

0,03

(30,4) 50 2,50(33,B 64,5 3,23(29,6 400 20,0 (1,7)

(8,5) 10 0,84(11,4 9,9 0,83 (7,6) 1272 106,0(B,9)

(7,4) 0,23(3,1) 29,6 1,29(11,8) 105564589 (3831

(16) 0,13(1,7) 2,B 0,07(0,6) 3BO 13,1 (1,1)

(50) 3,70 (50) 5,4 (50) 59B,0(50)

(95) 8,7 (7B)

11,3 4,06 352,5 126,0

7,5 2,67 6,4 2,3

00

Br =65mgll F = 1 mg/l H3 B0 3=26mgll Sr =13 mgll

94 E. ROMIJN

1956) in marl or claystones. Fossile salt deposits are also of great influence.

Another aspect is the capacity of clay minerals, glauconite and organic matter to adsorb or to exchange kations. A marine clay will exchange Na + for Ca ++ after coming into contact with fresh ground water containing Ca(HC0 3h, so that the ground water will contain NaHC0 3 • In case this ground water was saturated with CaS04 new sulfates can dissolve through this exchange of kations. Finally evaporation is of importance. For instance in the Sahara ground water is found locally with about 2000 mg CI/I (S c hoe I -ler, 1956), moreover it is assumed that salt water can "concentrate" because of earth gases which should cause water vapour to escape from the aquifer. The general tendency is that the percentage of salt in the ground water increases with depth, either through solution of minerals, through evaporation, or through contamination with fossil sea water (mixing, diffusion).

3. The influence of surface water. ~ When surface water (river water, sea water) infiltrates, for instance during storm surges, high river levels or by continuous land subsidence, the infiltrate will determine the composition of the ground water. Thereupon (bio )chemical changes and mixing with other ground water will take place. It is possible to study the processes in a geological sence; the artificial infiltration of river water in the dunes has also yielded important data (L ips et aI., 1969). The dune infiltration has proved that biochemical changes take place only in the first few metres of the soil, while adsorption is especially linked to the bottom ooze of the infiltration basin. Further down in the soil adsorption of organic matter and of P04= still occurs. Some analyses are given in table 3. See also V e win (1970).

b. Calculation methods

When calculating the exploitable quantity of ground water one ventures into the field of the systems engineer. By

ground-water level --t'-\-:--,I

FIg. 1 Outlme of a hydrologIC cycle.

systems engineering is meant: "The art and science of selecting from a large number of feasible alternatives, involving substantial engineering content, that particular set of actions which will best accomplish the overall objectives of the decision makers, within the constraints of law, morality, economics, resources, political and social pressures, and laws governing the physical, life and other natural sciences". (H a 11 & D r a cup, 1970).

In figure 1 the hydrological cycle is depicted, to be understood as a hydrological system, and to be subdivided into subsystems. The "art" is now to isolate and outline the subsystem in such a way as to make it suitable for calculations. Such an outline can be called a "model". These models can be distinguished into physical (hydraulic), analogue (electric, warmth) and mathematical (analytic, numerical) models. In figure 2 a diagram of the subsystem "discharge" is given (C how, 1964). In figure 3 this diagram

'rotal preCl PI tatl.on

Tnfl1 tratl.on I

0ther abstractions

I-~-l C'lJrface runoff Subsurface 'ieeo -percolatlon

(overland flow) rur,off I

i r ""J ''"": "'"""-."" I runoff

Prompt T\elayed

I subs. runoff subs. r 1 naff

L----r--;:~:~:~:::-~T

FIg. 2

I VOYles

DIrect

runoff L

"ase runoff

____ I~ __ J 'i'otal runoff

DIscharge (after V.T. C how, 1964).


FIg. 3

"'? == preCIpItatIon

F ::: infIltration towards unsaturated zone E == evaporation

T = transpiratlon

R = percolatIon towards saturated zone Qs = dlrect runoff

Qb = base runoff

Q = total runoff

DIscharge (after J.c.I. D 0 0 g e, 1968).

is more simplified. When schematizing even more, one loses sight of the relations within the (sub )system; the (sub )system becomes a "black box". The determination of the relationship between input and output of the "black box" can be carried out statistically.

In the calculations of the exploitable quantity of ground water, usually the "subsystem ground water" only is considered with as input: precipitation, subsurface inflow, and as output: evaporation, natural discharge (subsurface outflow and seepage) and artificial abstraction. The ground-water flow in the Netherlands is often practically horizontal. In this case the model can be:

continuity: div(Hy) = - O~~) ± Q(1), which means that at a

given moment the change in the flow rate (Hy) in a specific water column (H) equals the change in the stored ground

water O~tS) plus or minus infiltration or withdrawal (Q).

velocity: y = -K grad ¢ (2), which means that the seepage velocity y is proportional to the hydraulic gradient (grad ¢). Hereby H = thickness of aquifer, y = seepage velocity, t = time, S = storage coefficient of H, Q = discharge or recharge of the ground-water system, K = permeability coefficient, ¢ = potential or piezometric head.

Substitution gives: KH ,/ ¢ = S ~~ ± Q(3). Equation (3) can

only be solved analytically with simple boundary conditions, while with a more complicated soil structure and multiple phase flow the system parameters H, Sand K become more

complicated: K =~with k = intrinsic permeability [12] of 77

the medium, 'Y = specific weight of the fluid, 77 = dynamic

viscosity of the fluid (poise [~D, while Sand k are functions

of the coordinates. For further details the reader is referred to Verruyt (1970) and the Reports of the Commit tee for H y d r 0 log i cal Res ear c h TNO (1952 - present).

Furthermore the side-effects of ground-water abstraction

should also be considered, namely: the influence on the ground-water level with regard to damage due to drought (agriculture, horticulture, nature conservation) and subsidence, influence on brook and river discharge, influence on the subsurface flow, for instance with regard to the danger of salinization near the coast.

It is also of importance to recognize the influences which limit the ground-water abstraction such as pollution of water catchment areas or seepage of ground water of unwanted quality from elsewhere.

IV. EVALUATION OF GROUNO-WATER RESOURCES

a. The south of the Netherlands

1. South Limburg to the Feldbiss. - In figure 4 a survey is given of the structural units in the south of the Netherlands. The faults are taken from Zag w i j n (1971). South of the Feldbiss the following formations are aquifers.

At greater depths the Carboniferous contains salt ground water (table 3). Sometimes fresh ground water occurs above this salt water. In the mining district of South Limburg the limit of 10 mval CI- /1*) lies at 300 to 500 m below NAP (at faults and folds sometimes less deep). Both fresh and salt ground water show a zonation due to an exchange of kations: the upper Ca(HC0 3 h zone passes into a NaHC0 3

zone, which in its higher parts is still fresh (150 to 300 m thick), becoming more salty with depth until above the 150 to 200 mval CI- /1 level the ground water contains CaCl2

(K imp e, 1963). Part of the excess water (33 m3 /min. in 1968) of the coalmines which are successively closing could be used. To prevent those mines not yet closed from flooding, the mineshaft Beerenbosch II (Oomaniale Colliery) will discharge 10 to 18 m3 /min. in order to lower the water table down to a depth of NAP -170 m, whereby it is expected that only fresh water will be pumped (C r a s -b 0 r n et al., 1971). Here the Carboniferous surface is situated at NAP +l00 m; the ground level is at NAP +145 m.

The "Krijt" in Limburg (U pper Cretaceous to Palaeocene) is of importance for water production to the south of the Heerlerheide Fault only. The productive "Krijt" area is thus restricted to 470 km2 , the infiltration area to about 240 km2 . By multiplying this figure by the precipitation excess (= 35% of the precipitation of 750 mm/year) the area could yield 63 X 106 m3 /year (RID, 1965a). Of this amount only two thirds is economically exploitable (42 X 106 m3 /year; production in 1964: 26 X 106 m3 ). The "Krijt" water has a hardness of 15-20°0, the lowest layers (Akens and Hervens) contain softer water and in those places where the Akens and Hervens formations lie at a greater depth (100 to 300 m below NAP) fresh NaHC0 3 water (cf. Carboniferous) is found; beneath this level these formations contain salt water.

The Miocene ground water has a hardness of 12-14°0.

rug x valence IOnIC weIght

96 E. ROMIJN

tl o- . Pump."" .to toO" o r Woter SUPOI)f COIrID-O"", "'0011111:1 _0110 01 IJrOvll(l~

........... wal'l' 0& lOilS,."l.1I 1'11'71 (ou i pottlnlulh 01 cI •• p gt'oufld _wolor

o PI ' DC."'., 1I'1.,stOC4"''' (111011'1 1, ,.& .. ) ~M' OC.fI. (1963 )

...... 80ll"dOry O. mOrift. dtlPOll l ti 01

\_. ,,' [ ti m lO'IIIotion

Fig. 4

Ch l or l dtl conlont ot ~.tlPQO. wat.,. btll9W Ha l oc_nt! dtlpoul:.. E3 0. 30 0 11'1$11 '

~ 300 .1 000""$1/ '

m 100 0 -!)OOOmg/ l

_ )!)OOO mg/ l

SouRC£ De Wat.rFl" . •

The South of the Netherlands Inset Map salimty of ground water

The exploitable quantity (including the Wormvalley north of the Feldbiss) is estimated at 5 X 106 m3 /year (production in 1961: 1.9 X 106 m3 ) .

The Quaternary (the terraces of the Meuse) can produce about 30 X 106 m3 /year(production in 1961: 21 X 106 m3 ).

The water has a hardness of 14-20oD.

2. Limburg north of the Feldbiss and Noord-Brabant. -From the Upper Oligocene onwards the Roer valley graben has been sinking with regard to the Peel area . During the Neogene the Venlo graben was formed within the Peel area . The Pliocene (except for the Peelhorst of Limburg) and the Pleistocene are of importance for the water production . They are separated by thick layers of clay in the southeast of the Roer valley graben (formations of Brunssum and Reuver) . From the Pliocene of Middle Limburg (about 200 m thick) about 30 X 106 m3 of water can be obtained from below these clay layers (production in 1971 : 11 X 106 m3 , hardness 2_6°D; see table 3).

10 :Z:Okm L-__ L...' __ -I'

Elsewhere the Pliocene deposits (in Noord-Brabant mainly marine) , the Icenian and the coarse Pleistocene deposits of the Rhine and Meuse (Tegelen, Sterksel, Veghel and Kreftenheye formations) form a more or less uniform aquifer (base in the Peelhorst is at about NAP +10 m, in the Venlo graben at NAP - 60 m , in the Roer valley graben at NAP - 350 m) . In western Brabant the formations lie stepwise higher, in the southwest water is even abstracted from the Miocene (top at NAP - 60 m) . Hardness and iron-content of the water vary strongly (in Limburg hardness up to 16°D, Fe up to 35 mg/l), the marine Pliocene often contains harder water (in the west of Brabant 10-20oD).

Water balances have been made up for the whole area, while the relationship between brook discharge and groundwater level has been studied statistically for the drainage basins of the Grote Molenbeek (Peelhorst) , the Vlootbeek and the Dommel (Roer valley graben of Limburg and Brabant respectively). (RID, 1965b, 1967c, 1967d, 1972 and


Vis s c her, 1970). For the north and middle of Limburg the precipitation minus evapotranspiration has been estimated at 250 mm/year (=345 X106 m3 /year), of which 43 mm/year (=52 X 106 m3 /year) flows subsurface to the Meuse and 207 mm/year (=293 X 106 m3 /year) via the brooks and small rivers. Beyond the production of about 38 X106 m3 /year in 1965, a third of the subsurface flow of 52 X 106 m3 /year (=15 X lCf' m3 /year) and 345 m3 /ha over 11 00 km 2 (= 38 X 106 m3 /year) is still thought to be exploitable, whereby the ground-water table would fall by 10 cm on an average.

The excess precipitation in eastern Brabant (Roer valley graben) averaged 225 mm/year in 1953-1964, of which 180 mm was discharged via the brooks. Calculations show that at an extra production of 40 mm/year over 3000 km2

(= 120 X 106 m 3/year) the ground-water table would fall by 10 to 15 cm. This production of 120 X 106 m3 , added to the production of 100 X 106 m3 in 1964 and a consumption of ground water for sprinkler irrigation of 25 X 106 m3 , should result in a total of 245 X 106 m3 /year of exploitable ground water. The possible abstraction in the Reijen-Tilburg area is estimated at 30 X 106 m3 /year; in western Brabant this was recently estimated at 145 X 106 m3 /year (RID, 1972). Previously water-balance calculations (RID, 1965b) showed that the precipitation excess of some river basins (Mark and Weerijs) in western Brabant varied between 240 and 285 mm/year. The possible abstraction would amount to a third to one half of the precipitation excess. Furthermore the danger of salt encroachment in the west and northwest of Brabant should be kept in mind.

b. The Centre of the Netherlands

l. The area of the Great Rivers. - In the land strip between the German frontier and the city of Oordrecht (fig. 51 the base of the water-bearing layers are the fine, saline, marine formations of Upper Tertiary age and the Icenian. As the area is cut by faults (the displacement becoming smaller to the north) the tops of these formations are situated at different levels: Roer valley graben NAP -100 to -150 m, Peelhorst NAP -25 m (near Oss) or deeper (Lien den and Oruten NAP -50 m), Venlo graben NAP -75 to -100 m. Above the Icenian the Rhine-Meuse deposits of Pleistocene age are found, which in the Alblasserwaard are divided into two aquifers by clay layers of the Kedichem formation (top of Kedichem at NAP -20 to -50 m). The central and western areas are covered by Holocene clay-peat layers, which become thicker towards the west (to about 10 m). These layers are cut by old and often sandy river beds. To the west of Dordrecht, except along the Great Rivers, the deposits have been largely salinated by the Holocene transgressions (Calais, Duinkerke).

The whole area is surrounded by dikes; most of it is drained, causing seepage: in the area of the Alblasserwaard the seepage is about 82 mm/year (=47 X 106 m3 /year; RID, 1967a). For the area in the province of Gelderland a total

annual seepage has been calculated of about 130 X 106 m3 /year. In addition to this seepage water an extra amount of ground water could be produced, partly from induced river water and partly from the precipitation excess in the polders. Taking this into account the possible abstraction from the Alblasserwaard has been estimated at 50 X 106 m3 /year; in the area in the province of Gelderland at 200 X 106 m3 /year. It should be mentioned that domes of salt water exist locally, as for instance in the Alblasserwaard (to NAP -10 m) and near Zaltbommel (to NAP -20 m).

The ground water has usually a hardness of 10_20°0, containing 10-20 mg Cl- /1 and less than 20 mg S04' /1; however, under the influence of the seepage water of the polluted Rhine (table 3) one may find 20-150 mg Cl- /1 and 30-50 mg S04' /1 (5-25% of the anions; G e i rna e r t, 1972). At a greater depth a fresh NaHC0 3 -bearing zone is found as a transition to the salty ground water. Along the ice pushed hills of the province of Utrecht and the Veluwe -particularly under the Pleistocene clay layers - soft Ca(HC03 )2 containing water (hardness 5_7° D) is found coming from these hills.

2. Utrecht. - The Peelhorst on which the hills of Utrecht, consisting of ice-pushed strata of Pleistocene age, are situated, can still be recognized at greater depths. The base of the water-bearing layers is formed by the clay of the Tegelen formation. The top is at NAP -150 m near Montfoort (graben) and at NAP -100 m near Zeist (horst). Further to the north the top lies at about NAP -175 m. 50 m deeper yet Icenian deposits are found, partly consisting of sand. Above the Tegelen formation we find the river deposits of the Harderwijk and Enschede formations (of eastern origin) and Rhine deposits. In the west the aquifer is divided into two by the clays of the Kedichem and Sterksel formations (top at NAP -50 m). East of the hills the glacial basin with marine Eem layers is found (see "Gelderse Vallei"). West of the hills Holocene clay-peat layers (to 10 m thick) cover the aquifer. The quality of the water it' the low western part of the province of Utrecht is similar to that in the area of the Great Rivers. In the hills it is similar to that of the Veluwe (G e i rna e r t, 1972). In the northwest the water is saline because of salt water seepages in the deep polders near Mijdrecht. A rough water balance has been drawn up for the "Eem Vallei' , (900 km2 , of which 450 km2 are covered by Eemian). The precipitation excess amounts to about 290 mm/year (=4.1 m3 /sec). The seepage is 0.7 mm/day (= 3.8 m3 /sec). The discharge at the river-mouth of the Eem is 11.4 m3 /sec, the difference of 3.5 m3 /sec comes from household and industry effluents and from the tributary rivers. In this area research on the exploitable quantity of ground water is still going on. For some areas in Utrecht provisional water balances have been made up (RID, 1970a), from which it appeared that from the low western and southern parts about 14 X 106 m3 /year could be obtained frem influent ground water and about 68 X 106 m3 /year from the precipitation excess (200 to 300 mm/year). Furthermore 40 X 106 m3 /yea:

98

Fig. 5 The Centre of the Netherlands. Legend see fig. 4.

E. ROMIJN

10 I

/J SSE L M E E

99 DEVELOPMENT OF GROUND-WATER RESOURCES IN THE NETHERLANDS

could be obtained from the ice-pushed hills, 7 X 106 m3 /year from the western part of the "Eem Vallei", and perhaps 10 X 106 m3 /year of deep ground water from below the clay of the Tegelen formation. In total it amounts to about 140 X 106 m3 /year. Of the seepage in the "Bethune" polder 25 X 106 m3 /year is delivered to the municipal water works of Amsterdam as surface water.

3. Gelderse Vallei, Veluwe and southern Ilsselmeer Polders. - The hills of the Veluwe - pushed by the glaciers during the Saalian period - consist of Pleistocene fluvial deposits of eastern and southern origin. They are surrounded by deepcut glacial valleys such as the "Gelderse Vallei" and the "Usselvallei" (down to NAP -100 m). Here again the base of the aquifer is formed by the clay layers of the Tegelen formation: the top in the "Gelderse Vallei" decreases from NAP -75 m in the south to NAP -175 m in the north; the top in the Veluwe decreases from NAP -80 m in the south and northeast to NAP -200 m along the "Usselmeer" coast. These glacial valleys are mainly filled up with glacial and Eemian layers of clay which are covered by layers of very fine sand of the Weichselian period. (In the "Usselvallei" also the coarser deposits of the Kreftenheye formation are encountered).

In the report of the committee Van Dissel (Van Dis s e 1, 1933) the precipitation excess in the infiltration area of the Veluwe was estimated at 200 to 250 mm/year. Recently it has been estimated at 350 mm/year (RID, 1970b). For an infiltration area of 1270 km2 this is about 400 X 106 m3 /year. It is estimated that about half of this amount can be abstracted namely about 60 X 106 m3 /year from the ice-pushed hills, about 55 X 106 m3 /year from below the glacial and Eemian clay layers in the "Gelderse Vallei", about 20 X 106 m3 /year from the "Usselvallei" (west of the Ussel) and about 20 X 106 m3 from the coastal strip, while another 55 X 106 m3 /year could be obtained from the southern border of the Veluwe. The total amount would be about 210 X 106 m3 /year (RID, 1970b).

The ground water from the ice-pushed hills and from below the Young Pleistocene clay layers is soft (hardness 5°D), with a content of less than 20 mg/l of both Cl- and SO; . The upper water layers in the ice-pushed hills are often aerobic. The iron content is usually less than 1 mg/l (table 3).

The clay layers of glacial and Eemian age are also found below the polders of the Usselmeer (fig. 5). In the centre of South Flevoland they reach to a depth of NAP -130 m. The natural infiltration water coming from the Veluwe flows partly below these clay layers to the Usselmeer (see fresh-water tongues, fig. 4). This underground drainage amounts to about 100 X 106 m3 /year. With an intensive ground-water production in the Veluwe this underground discharge could be reduced by half; perhaps 25 X 106 m 3/ year of this water could be abstracted in the IJsselmeer polders. The still saline Weichselian layers above the Eemian clay will eventually become fresh because of the seepage of fresh water from the IJsselmeer to the polders so that it

might become possible to produce water from the shallow aquifer. The total amount of abstractable ground water within the U sselmeer polders has provisionally been estimated at 30 X 106 m3 /year at the maximum expansion of the water production in Gelderland. Research on the abovementioned regions is still in progress.

c. The north and east of the Netherlands

1. Achterhoek (see fig. 6). - A number of studies have been carried out on the consequences of ground-water abstraction in the Achterhoek (D e V r i e s, 1967; B r u y n, 1970). Today the Achterhoek serves as an experimental area for the realization of a water management model in which amongst other things the relationship between ground-water abstraction and the damage to agriculture is being studied.

From a hydrological point of view the area of the "Oude IJssel" is a favourable region for ground-water abstraction. From April 1954 to March 1969 the precipitation averaged 822 mm/year, the discharge at the weir of Doesburg amounted to 303 mm/year and 40 mm/year was calculated for seepage and loss through locking. If 40 mm/year of this excess precipitation of 343 mm/year would be pumped, then the ground-water table would decrease to 20 cm in spring and less than 35 cm in autumn, except near the wells themselves (B r u y n, 1970). According to other calculations the drought damage to the agriculture could amount to 10% of the normal yield at a total ground-water abstraction of 90 X 106 m3 /year spread over the Achterhoek. However, if the location of the production wells are well chosen (for instance in the valley of the "Oude Ussel") the damage will be less.

The geohydrological structures are complex. East of the line Neede-Aalten coarse high-terrace deposits (5 to 10 m thick) form local remnants. They lie directly on the impermeable Tertiary deposits (top of these near Eibergen is at NAP +20 m, east of Winterswijk at NAP +40 m). East of Winterswijk the Mesozoic deposits lie at less than 50 m below surface. Their tectonic structure is determined by the east-west trending upthrust of Winterswijk. South of the upthrust amongst others Cretaceous limestone is found, north of it Mu.schelkalk and Bunter. These formations are possibly aquifers. West of the line Neede-Aalten the Tertiary (top near Doetinchem at NAP -40 m, near Doer.burg at NAP -75 m) lies deeper. Some north-south oriented valleys, filled with glacial sands and clays, reach down to the Tertiary ("Usselvallei", the valley west of the line Neede-Aalten and the valley Haaksbergen-Aalten-Dinxperlo). Locally they reach down to a depth of NAP -70 m. Between the valleys ice-pushed Pleistocene deposits are found; in the valleys continental Eemian deposits (containing organic matter) are found at NAP-level and on top of the Eemian we see coarse Rhine deposits which are covered by fine sands (Weichselian).

Along the terrace border (west of the line Neede-Aalten), along the Berkel, the Oude IJssel and the Ussel the deeper

100 E. ROMlJN

Fig. 6 The North and East of the Netherlands. legend see fig. 4.


ground water has an over-pressure and seepage occurs. This ground water is often harder (> 15°D) than in other areas. Especially in the area Borculo-Lichtenvoorde the iron content is high (I5 to 20 mg/l) , while on the other hand the sulfate content is low. This is probably due to the presence of organic matter in the Eemian layers. The quality of the ground water in the ice-pushed areas is similar to that of the Veluwe.

2. Overijssel. - In Twente just as in the Achterhoek, and especially east of the line Neede-Almelo, impermeable marine layers of Tertiary age occur close to surface. Glacial valleys surrounded by ice-pushed hills are cut in north-south direction. East of Enschede Lower Cretaceous sand and sandstones occur locally at shallow depth below the Tertiary. Near Losser the top of the Lower Cretaceous is at 1 GO m below surface (which lies at NAP +45 m) and water is produced from this layer. Nothing is known about the possibilities of a drinking-water production from the Bunter (top near Buurse is at 65 m below surface, Rot salt layers, however, are at NAP -250 m or deeper) or from the Muschelkalk (south of Hengelo-Enschede at NAP -100 m). To the north and west the Tertiary layers lie deeper, so that Pleistocene river deposits are found as an aquifer. West of the Holterberg and of Heino the continental Pliocene sediments change into sandy marine Pliocene, while to the west the marine Pliocene is covered by Icenian (top near Deventer at NAP -100 m, near Zwartsluis at NAP -140 m). The "I1sselvallei" contains glacial deposits (often clay) which, north of Zutphen, sometimes reach down to NAP -100 m. In the valley of the Vecht the glacial deposits reach down to NAP -50 m. The upper layers in these valleys consist of coarse river deposits (Kreftenheye formation) with a thickness of some tenths of metres (locally continental Eemian clay occurs in these deposits). At surface nearly the whole province is covered by fine sand (Weichselian).

Only recently a salt water encroachment has been observed near Deventer, where water is obtained from below the glacial clay. The waters in the North East Polder and in the corner between the river I1ssel and the Zwarte Water are largely saline (fig. 4).

Water-balance calculations have been made in some smaller areas (RID, 1968). In the area of the "Weteringen" of Salland (to the west of the Holterberg) the precipitation averaged 767 mm/year over the period 1953-1965 of which 335 mm/year infiltrated and was later discharged by the brooks. The average discharge in summertime over the period 1953-1965 amounted to 10 mm/month. If half of that amount (5 mm/month) would be abstracted over two thirds of the area (= 12 X let m3/year) in addition to the already existing production, the ground-water table would fall about 10 cm according to the statistical relationship between brook discharge and ground-water level. From the balance of the river basin of the Regge a precipitation excess has been calculated of 387 mm/year and an average discharge of 18 mm/month in summertime. An additional production of

25 X 106 m3/year would decrease the ground-water level by about 5 to 25 cm. In the basin of the river Vecht it would be possible to abstract a supplementary 36 mm/year over two thirds of the area (= 15 X 106m3/year). In the area ZwolleDeventer a supplementary 3 X 106 m3/year and in northwest Overijssel a supplementary 50 X 106 m3/year could be obtained. Here some polders are situated which show severe seepage (the seepage in the "De Koekoek" polder is 35 to 40 X 106m3/year). Nevertheless the danger of salt water encroachment exists. A total supplementary quantity of 105 X 106m3/year of ground water could eventually be produced. Research, especially in Salland, is still in progress.

3. Friesland, Groningen. Drente. - Research on the possible ground-water production in Drente and the east of Groningen is still in progress. In older reports on Drente (RID, 1967b, reviewed in 1969) the total of abstractable ground water is indicated at 200 X 106m3/year, of which 120 X 10 6m 3/year could be produced from the "Drents plateau". In figure 6 the infiltration area of the "Drents plateau" is very obvious. In contrast to the Veluwe, the precipitation infiltrating into the soil is soon drained by the brooks due to the type of drainage system and because clay layers are present just below surface (most of these layers are part of the ground moraine of the Saalian). From waterbalance calculations of the river basins of the Amer- and Loonerdiep, the Eelderdiep and the Wold A as made over the years 1953 to 1964 the precipitation excess in these areas are found to be 389, 346 and 347 mm/year respectively. For the whole of the "Drents plateau" (1500 km 2 ) 360 mm/year was taken as an average (=540 X 106m3/year, of which 38 mm/year would discharge into the subsurface and 322 mm/year would run off via the brooks (RID, 1967b). To the east the plateau is bounded by the Hunze valley and to the south by the Vecht valley, both partly filled with fluvioglacial sands. The glacial deposits (Saalian) which are covered by fine sands (Weichselian) disappear towards the north and west under the Holocene clay and peat layers; in the south and east of Drente and in the east of Groningen vast areas of (largely removed) peat moor are found. Below the glacial deposits (Saalian) and the Eemian clay layers (Hunze valley) the actual aquifer is found consisting of Pleistocene river deposits of eastern, southern and local origin and of Pliocene river depOSits. The base (marine Tertiary and in the west the Icenian) is found to the north and west at a gradually increasing depth (top near Emmen is about NAP -60 m, near Terwisscha at about NAP -160 m). The structure of the aquifer is complicated because of the occurrence of deep valleys (deeper than NAP -100 m) filled with "pot clay" (formation of Peelo/Elsterian) which is often found directly below the Saalian. Moreover, the diapiric structures in the northeastern Netherlands complicate the situation (Zechstein salt domes, e.g. the dome of Schoonlo where the caprock reaches up to 150 m and the salt to 225 m below surface). For further information see Gis chi e r (1967) and the Rep 0 r t Bas i s p I ann e n N 0 0 r d (1970).

102 E. ROMIJN

The ground water produced in Drente is of the Ca(HC03)2 type with a varying hardness (usually < 10°D) and a varying iron content (0.1 to 2l.6 mg/l). These variations can mostly be explained by the presence of the peat layers. In Friesland the produced ground water becomes harder towards the north and west (to ISoD). Immediately south of the city of Groningen the hardness amounts to 14°D. In the vicinity of the saline areas the ground water contains NaHC0 3 just as near the marine Pleistocene layers of the Eemian in the Hunze valley.

As has been mentioned above, about 120X 106 m 3 /year (=SO mm/year) could be produced from the "Drents plateau". Furthermore about 30 X 106 m3 /year (= SO mm/ year) could be produced in southeastern Drente (area of the Loo- and Drostendiep and the Schoonebekerdiep) and 50 X 106 m3 /year (= 60 mm/year) in the east, south and west peat moor areas of Drente, a total therefore of 200 X 106 m3 /year. In the province of Groningen fresh water can be found over an area of about SOO km 2 (150 km 2 in the southwest and 650 km2 in the southeast). The Westerkwartier as well as Westerwolde could produce about 10 X 106 m3 /year. The pumping stations Haren and Onnen, southeast of the city of Groningen, are not allowed to produce more than 2 X 106 and 15 X 106 m3 /year respectively (R e p 0 r t Bas i s pia nne n No 0 r d, 1970) as otherwise there will be the danger of salt water encroachment. The total for Groningen will therefore amount to 37 X 106 m3 /

year. In Friesland the possible abstraction has been calculated at 100 mm/year over an area of 1500 km 2

(=150 X10 6 m 3 /year).

d. The north and west of the Netherlands.

The ground water of the lower part of the Netherlands has become saline (fig. 4) by Holocene transgressions, by diffusion of salt water from the marine Pleistocene layers and by seepage of sea water in the polders. Due to precipitation the drained first few metres near surface contain fresh water, allowing farming. Ground-water abstraction is only possible in those areas where a sufficient amount of precipitation or river water can infiltrate, i.e. in the dunes along the coast, in the ice-pushed hills of the Gooi and alc,ng the Great Rivers. As the most densily populated areas are situated in the west of the Netherlands, ground-water abstraction has been the object of extensive studies.

In the catchment area of Leiduin for instance the precipitation excess has been measured with lysimeters amounting to 460 mm/year. A number of studies (G erne e n t e w ate r 1 e i din g en, 1940, 1945; Ed e 1-m a n, 1947) indicated that because of the abstraction of fresh water from below the Holocene clay layers, which started in 1903, the fresh-water lense of Leiduin had been reduced by 230 X 106 m3 in 50 years' time.

The abstraction of water from shallow depth occuring in many dunes caused a drying up resulting in damage to the vegetation, especially to woody plants (C e n t r ale

Com m iss i e, 1940) and the disappearance of the moist dune valleys with their unique flora. In the last-named report much attention was paid to recreation and nature conservation. The conclusion was reached that judicious management would serve best the interest both of the drinking-water supply and of the recreation and nature conservation. The maximum allowable withdrawal of ground water was estimated at 270 mm/year over an area of IS7 km2 representing the catchment area of the dunes (= 205 km2 ) in the provinces of North and South Holland, amounting to 50 X 106 m3 /year (in 1935 the production already was 57 X 106 m3 /year!).

From 1940 onwards artificial infiltration of river water in the dunes was applied more and more often to prevent the welling up of salt ground water; table 3 gives the composition of natural dune water. In a number of studies the possibilities to obtain drinking water from the dunes of the islands of the provinces of Zeeland, South Holland and the Wadden Islands has been investigated. It became apparent that no expansion of the present production is possible. Locally artificial recharge is applied (Goeree, Zeeuws Vlaanderen).

Research on ground-water abstraction in Het Gooi (RID, 1956) proved thatlS X 106 m3 / year of fresh water can be produced without any risk of salt water encroachment.

In the province of South Holland the possible abstraction of ground water is estimated at 140 X 10 6 m3 /year (S t u die Com m iss i e, 1965) of which 13 X 106 m3 /year would be fresh dune water without artificial infiltration. Along the river Oude Rijn it would be possible to abstract 10 X 106 m3 /year, along the Lek (Krimpenerwaard) 30 X 106 m3 /year, in Oost IJsselmonde, the Hoekse Waard and the Island of Dordrecht possibly 37 X 106 m3 /year and in the Alblasserwaard and Vijfheerenlanden 50 X 106 m3 /year (see area of the Great Rivers). The possible production from the area along the Oude Rijn appears to have been over-estimated (saline problems). It should be mentioned that the water obtained from the area along the Great Rivers will partly consist of induced water of doubtful quality.

V. CONCLUSIONS

The above-mentioned studies have been used to draft the Masterplan for the Future Water Supply. In this plan, however, some quantities of ground water which could be exploited have been amended.

As the exploitation of ground water from the Carboniferous and deeper Pli6cene layers in Limburg is doubtful, only 190 X 106 m3 /year can. be counted upon. From the given data it can be assumed that the province of NoordBrabant could produce 420 X 106 minus 25 X 106 (for sprinkling water) amounting to a total of 395 X 106 m3 /year. From this amount 15 X 106 m3 /year must be delivered to Zeeland which province can produce only 5 X 10 6 m3 /year. In the province of Gelderland some 500 X 106 m3 /year should be abstractable (area of the Great Rivers 200 X 106 ,


Veluwe 210X 10 6 , Achterhoek 100 X 106 ). However, the Masterplan is counting upon only 140 X 106 m3 /year for the area of the Great Rivers, thus giving a total of 450 X 106 m3 /year. Utrecht will allow 30 X 106 m3 /year of seepage water from the Bethune polder to be delivered as surface water to Amsterdam, thus leaving some 110 X 106 m3 /year as exploitable ground water. Overijssel (table 4) produced about 75 X 106 m3 /year in 1967. With the possibility of a supplementary ground-water production of 105 X 106 m3 /year a total of 180 X 106 m3 /year is exploitable. From this amount 30 X 106 m3 /year is reserved for sprinkling water, leaving about 150 X 106 m3 /year for the supply of drinking water.

The ground water abstracted by the industry in the provinces of North Holland and Groningen, although stated by the C.B.S. as fresh water (table 4), is probably brackish. Groningen is therefore listed for only 40 X 106 m3 /year and North Holland for only 50 X 106 m3 /year.

TABLE 4 Ground water resources in 106 m3 /year -

Maximum 1967 1971 fresh water C.B.S. V.E.W.I.N. avauable

Provmce (Water-Industry Water- Water- works +

fresh salt works works Industry)

Fnesland 26.3 2.0 24.6 33.7 150 Gromngen 13.9 5.2 28.1 25.7 40 Drente 28.9 30.8 40.9 200 Overi]ssel 29.9 46.6 55.3 150 Gelderland 103.4 67.8 87.7 450 Utrecht 17.6 44.9 55.8 110 Noord Holland 30.3 33.5 57.0 54.4 50 ZUld Holland 30.2 2.2 46.1 59.1 130 Zeeland 0.1 2.5 4.2 4.3 5 Noord-Brabant 86.0 0.2 103.7 139.3 395 Limburg 60.6 0.2 41.0 53.2 190 S. IJ sselmeer

Polders 0.6 1.9 30

The Netherlands 427.2 45.8 496.0 611.3 1900

The total amount of fresh ground water produced in the Netherlands amounted to 1.1 X 109 m3 in 1971.

ACKNOWLEDGEMENTS

The author wishes to thank Mr. T. Verheul, director of the RID, for his kind permission to publish the provisional results of these studies.

REFERENCES

Bnef van de Staatssecretans van Soclale Zaken en Volksgezondheld (1969) - De toekomstlge dnnkwatervoorzlenmg van Nederland. Staatsuitgeven], 's-Gravenhage.

Bruyn, J. (1970) - Dalmg van de grondwaterstand als gevolg van grondwateronttrekkmg. H20 (3) no. 23.

Centrale Commissle voor Drinkwatervoorzlenmg (1940) - Rapport van de Commissie Drinkwatervoorzlening Westen des Lands. StaatsultgevenJ, 's-Gravenhage. (1967) - De toekomstIge dnnkwatervoorzlemng van Nederland. Staatsuitgevenj, 's-Gravenhage.

Chow, V.T. (ed) (1964) - Handbook of Hydrology. McGraw-Hill. New York.

Committee for hydrologIcal research TNO (1952 - present) -Proceedmgs and InformatIOns, 's-Gravenhage.

Crasborn, 1.R.P., H.N. van den Heuvel, W.F.M. Klmpe, W. Maas, (1971) - Mijnwaterproblemen m het kader van opeenvolgende mi]nsIUltmgen. Geol. en Mljnb. (50) Mijnsluitingsnummer.

Dlssel, E.D. van (1933) - Wateronttrekking aan de Veluwe. Staatsuitgevenj, 's-Gravenhage.

Edelman, J.H. (1947) - Over de berekening van grondwaterstrommgen. TheSIS Delft.

Gemeentewaterleldmgen (1940, 1948) - De watervoorzlemng van Amsterdam. Gemeente Amsterdam.

Geunaert, W.C. (1972) - CompositIOn and history of ground-water in the Netherlands. Thesis Leiden.

Glschler, C.E. (1967) - A semi qualitative study of the hydrogeology of the North Netherlands. Trans. KNGMG, Geol. Sene no. 24.

Hall, W.A., 1.A. Dracup (1970) - Water resources systems engmeermg. Mc Graw-HIlI, New York.

Jelgersma, S., W.A. Visser (1972) - Hydrogeological maps of the Netherlands. Geol. en Mljnb. (51) no 1.

Klmpe, W.F.M. (1963) - Geochlmie des eaux dans Ie HOUlller du Limbourg (Pays-Bas). Trans. KNGMG, Geol. Serie no 21.

LIps, H.J.M., B. Bulten, J. van Puffelen (1969) - Kwaliteltsverandermg bl] mfiltratle in de dumen. Unpubbshed report of the WIRDU, 's-Gravenhage.

Nes, B.A. van (1965) - Raming van de beschlkbare hoeveelheld grondwater m Nederland. Water (49) no 7.

Rapport Baslsplannen Watervoorzlenmg Noord (1970). Roml]n, E. (1972) - ReView of geohydrologlcal actlVltIes m the

Netherlands smce World War II, m partIcular of the Government Institute for Water Supply. Geol. en MIJnb. (51) no 1.

Rljksmstituut voor Drmkwatervoorzlening (1919a) - Rapport betreffende een centrale dnnkwatervoorziemng voor de provmcle FrIesland. StaatsuItgevenj, 's-Gravenhage. (1919b) - Rapport betreffende de centrale dnnkwatervoorzlenmg m ZUld-Holland, Noord-Holland en Utrecht (CDV). StaatsUltgevenj, 's-Gravenhage. (1956) - Nota mzake de gevolgen van een vergrotmg van de wateronttrekkmg aan het GOOI. (RID, unpublIshed). (1965a) - De dnnkwatervoorzlenmg m ZUld-Limburg, nu en m de toekomst. (RID, unpublIshed). (1965b) - Grondwaterwinmng m westelijk Noord-Brabant. (RID, unpublished). (1967a) - GeohydrologIsch onderzoek van de Alblasserwaard en de VIJfherenlanden t.b.v. de toekomstIge dnnkwatervoorzlemng. (RID, unpublIshed). (1967b) - Grondwaterwinnmg m de provlncle Drente, (herzlenmg 1969), (RID, unpublIshed). (1967c) - Grondwaterwmmng m de provincle Noord-Brabant. (RID, unpublIshed). (1967d) - Grondwaterwmmng m Mldden- en Noord-Llmburg. Nu en in de toekomst. (RID, unpublIshed). (1968) - Grondwaterwmnmg in de provmcle OveriJssel. (RID, unpublIshed). (1970a) - De winbare hoeveelheid grondwater m de provmcle Utrecht. (RID, unpublIshed). (1970b) - Nota mzake de mogelijkheden voor de grondwaterwmmng op de Veluwe. (RID, unpublIshed). (1972) - Rapport betreffende het reglOnaal geohydrologlsch onderzoek in het zandgebied van westelijk Noord-Brabant. (RID, unpublished).

104 E. ROMIJN

Schoeller, H (1956) - Geochlmie des eaux souterrames. ApplicatIOn aux eaux des gisements de petro Ie. Inst. Fran~als du petro Ie, Paris.

Studiecommissle organisatle drinkwatervoorzlemng ZUld-Holiand (1968) - De toekomstlge dnnkwatervoorzlening m ZUld-Holland.

TransactIOns of the Jubilee ConventIOn (1963) - Trans. KNGMG, Geol. Sene no 21.

Verruyt, A. (1970) - Theory of groundwater flow. MacMillan, London.

VEWIN (1970) - Statlstlsch overzlcht der Waterleidingen m Nederland overdejaren 1964 tot en met 1967.

Visscher, W. (1970) - Regionaal geohydrologlsch onderzoek bij de bepaling van de optlmale grondwateronttrekking in een groot stroomgebied. H20 (3) no. 4.

Vries, J.1. de (1967) - De consequenties van grondwateronttrekkmg m de Achterhoek. LC.W. nota no 423.

Westerveld, J. (1951) - De schelkundige samenstelhng der aarde Servue, 's-Gravenhage.

Zagwijn, W.H. (1971) - Toehchtmg blj de voorlopige kaart "Breuken ill het kwartair van Zuid- en Midden-Nederland". schaal I. : 250.000 (RGD - Haarlem, unpubhshed).

ZUidema, R. (1970) - Verkort eindrapport van de werkgroep waterverbrUlk. Grondslagen Basisplannen 9. H2 0 (3) no. 26.


AN EAST-WEST GEO-HYDROLOGICAL SECTION ACROSS THE NETHERLANDS

J.B. BREEUWER 1 ) and S. JELGERSMA1 )

1. INTRODUCTION

A large amount of sediments was deposited in Tertiairy and Quaternary times in the Netherlands, situated at the edge of the subsiding North Sea basin. The base of the Quaternary in the northwest and west Netherlands lies between 300 and 500 m below sea level.

In the Central Graben, the Peel High and the Venlo Deep the base of the Quaternary lies at a depht between 150 m and 250 m. In the eastern, southern and southeastern parts of the Netherlands the Quaternary is much thinner. In these areas the Tertiary sediments subcrop near the surface; here also Mesozoic and Palaeozoic strata lie near or at surface.

It can be stated that for the water supply only the uppermost 200 m of strata are of interest, not only for technical reasons, but also for the fact that salt water is often found at less than 200 m below surface. Therefore potableand industrial water is produced from the Quaternary only in large areas of the Netherlands. In South Limburg the Upper Cretaceous and Miocene and Pliocene sediments are the main aquifers.

However, in the area as pictured in the section (fig. 1), the main production of waters is from the Quaternary.

Due to the alternation of glacial, interglacial and interstadial periods the sedimentation in the Quaternary was rather varied. In large parts of the country mainly fluviatile sands were deposited by the Rhine, Meuse, Ems and Weser. These sands have a high porosity and are therefore of importance for the water supply.

During the Saalien glaciation clays and other glacial clays were deposited. As a result of the advancing ice-tongues deep glacial valleys and hilly ice-pushed ridges came into being. These morphological features are of importance for the hydrogeology. The sometimes 100 m high, ice-pushed ridges lowered the salt water - fresh water boundary considerably. Not all deep glacial valleys have been filled with sediments at once. Therefore, the Eem sea could transgress far inland using these pre-existing valleys during the interglacial Eemien

1) R1Jks GeologJsche Dienst, Spaarne 17, Haarlem, The Netherlands.

period, following the Saalien. This caused a considerable increase in the salt content of the ground water. The same phenomenon took place again during the Holocene transgression.

The morphology of the northern and eastern parts of the country, as a result of the ice action, together with the subsidence of the North Sea basin, are mainly responsible for the present situation of the "Low Lands", where brackish to salt water is found from surface to great dephts.

II. DESCRIPTION OF THE CROSS-SECTION

The East-West section through the centre of the Netherlands (Wassenaar-Lattrop) gives a profile of the Quaternary and Tertiairy deposits. At first sight a division into two lithological units can be made:

a. The upper 100-150 m consisting mainly of coarse sands with intercalated clay beds.

Between Wassenaar and Driebergen two important aquifers of Pleistocene age can be distinguished:

the formations of Sterksel, Urk and Kreftenheye; - the formation of Harderwijk.

These two aquifers are separated by the clays of the Kedichem formation and covered by the clays and peat layers of Holocene age.

Near the coast the Holocene dunes form a third and important aquifer. Below the dunes a deep fresh water pocket is found. In this area the two above-mentioned Pleistocene aquifers contain only salt water.

More eastward towards Utrecht the lowest aquifer, the Harderwijk formation, becomes the most important.

In the eastern part of the section between Driebergen and Vriezenveen a twofold division in the fresh-water bearing layers can be recognised. Over large areas fluvio-glacial clays of the Drente formation are present, separating the two aquifers: above the Kreftenheye formation and below the Enschede and Harderwijk formations.

Below the ice-pushed ridges we find in general only one

106 J.B. BREEUWER & S. JELGERSMA

aquifer. Dipping loam layers are causing irregularities in the ground water pattern.

Near Raalte the deepest aquifer is of Pliocene age. To the east of Raalte impermeable layers of Miocene age subcrop at a low angle close to surface.

b. Below 150 m depth fine-grained sands and clay beds are found to be considered as the base of the main aquifer in the Netherlands.

In the east these lower beds consist of Oligocene marine

clays, sub cropping not far below surface. In the western part of the section in the province of Zuid-Holland the Oligocene clays lie at about 600 m depth. Here the marine Icean deposits and the fluviatile deposits of the Tegelen formation are the base of the aquifers.

The marine beds of Miocene also lie near surface in the eastern part. The shell and glauconite bearing, finegrained marine sands of Pliocene age are of low permeability and contain salt or brackish water, which in this part of the section could be considered as fossil water of Tertiary age.

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New aspects of mineral and water resources in The Netherlands

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Transcript of New aspects of mineral and water resources in The Netherlands