Method of Developing and Equipping a 21st Centaury Haulage ...

1/23

MMeetthhoodd ooff DDeevveellooppiinngg aanndd EEqquuiippppiinngg aa 2211sstt CCeennttaauurryy

HHaauullaaggee aatt DDeepptthh

JD SPIES

General Manager, (Moab Khotsong Mine)

A BLOM

Section Manager, (Moab Khotsong Mine)

SYNOPSIS

This paper describes the methodology and design of tunneling at depth of the Moab Khotsong

project. It deals more in depth with the innovative excavation techniques and tunneling standards

employed whilst developing through weak MB 10 guartzites in order to access the orebody safely.

INTRODUCTION

The Moab Khotsong project forms part of Anglogold Vaal River Operations. The operation in

addition to the project consists of three other production mines situated near Klerksdorp in the

North West Province (see Locality Plan – Figure 1). Following the successful exploration of the

down dip extension of the Vaal Reef, situated to the south of the Great Noligwa Mine, it was

decided to exploit the orebody.

The orebody lies at depths between 2 000m and 3 800m below surface with only limited quantities

of ore lying above 2 300m. The geological structure is complex and highly faulted with large fault

loss areas. Due to the size of shaft pillars, as well as the fact that they cannot provide the necessary

protection against rock pressures at depth, it was decided to site the new shaft in Great Noligwa’s

lease area. This provided the opportunity of extracting the shaft pillar before the shaft was

excavated and equipped but required the development of long access tunnels to reef. The main

surface shaft and sub – vertical has been sunk and equipped down to a depth of 2 300m and 3 164m

respectively (see Shaft Layout – Figure 2 & 3).

The infrastructure and the access development on the first two levels will be excavated by means of

a mid shaft loading system. Inter level spacing on these levels are 300m apart, and this decision

was taken in order to reduce access development meters to the reef blocks which are 2 500m away.

A mid shaft loading system which consists of a single skip / cage combination with a 1 000 ton/day

hoisting capacity, limits the volume of development that can be excavated and serviced.

GEOLOGICAL INFORMATION

The upper levels are situated in the Commonage Formation, which is a fairly monotonous quartzite

with scattered white grains. The bedding thickness can vary up to 135 cm with intermittent thin

shale bands that could cause stability problems (avg. U.C.S.: 121 – 235 MPa). Abundant small

scale faulting is present as well as associated joints giving the rock formation a fractured

appearance. Major faults are also present with numerous sill and dyke intersections.

2/23

LOCALITY PLAN

TAU LEKOA

MINE

KOPANANG MINE

GREAT NOLIGWA

MINE

MOAB KHOTSONG

MINE

N

ORKNEY

KLERKSDORP

PROPOSED DECLINES FOR LOWER

REEF BLOCKS

101 LEV

95 LEV

85 LEV

SOUTH

VAAL

LEASE

EAST VAAL

LEASE

SUB RV

SHAFT

MAIN SHAFT

REEF

FAULT

FUTURE MAIN SHAFT EXTENSION

102 LEV

Figure 1

Figure 2

3/23

Figure 3

TUNNELING

Strategy

Definite tunneling strategies had to be formulated for Moab Khotsong as current mining methods

cannot simply be extended to deep level mines without compromising safety and would require

significant modifications to standards, work practices and mine design. During station development

on the main shaft it became apparent that because of poor ground conditions, conventional methods

of tunneling would not suffice on Moab Khotsong Mine where greater depths are anticipated. This

therefore necessitated that certain principal decisions be made that will ensure safety, be practical

and cost effective. In addition these decisions should be aligned with the horizontal transport vision

of a 21st century mine. The principal decisions and any subsequent decisions taken will be

discussed in detail under each aspect of tunneling.

Mine Design

The decision was taken to develop a main haulage and return airway with connecting crosscuts

100m apart on the two levels serviced by the mid shaft loading system because of the hoisting

constraint (see Figure 4). This limited the planned rate of advance to 180m per level per month (see

Production Profile).

> >

11F & G

11C

11B

11H

11E 11D

11A

Sub Main Shaft

RV Shaft Main Shaft

Lease Boundary

MOAB KHOTSONG PLAN

Great Noligwa

N

MINED ABOVE 101 LEV.

MINED BELOW 101 LEV

4/23

85 LEVE

L

MB 10 Quartz

ite

85 LEVEL85 LEVEL

Figure 4

Equipment Selection

From a workshop involving Technical Development Services it was decided to use handheld

jackhammers due to the length of round and support requirements in conjunction with LHD’s.

Tunneling commenced in August 1998 with jackhammers and diesel driven LHD’s in order to

complete all the infrastructure development around the shaft barrel. Subsequently the necessary

infrastructure was installed to accommodate track – bound equipment to follow 100m behind the

access development with electro – hydraulic LHD’s tipping directly into hoppers at established

tipping points.

MM..SS..DD.. PPRROODDUUCCTTIIOONN PPRROOFFIILLEE

0

50

100

150

200

250

300

350

400

450

Dev Act 106 274 317 348 366 365

Dev Plan 80 120 260 300 340 360 360 360 180 260 300 340 360 360 360 360 380 400

Jul-99 Aug-99 Sep-99 Oct-99 Nov-99 Dec-99 Jan-00 Feb-00 Mar-00 Apr-00 May-00 Jun-00 Jul-00 Aug-00 Sep-00 Oct-00 Nov-00 Dec-00

5/23

Mining Cycle

From the outset it was envisaged that 3 crews would be required to work 12 hour shifts. The main

reason behind this decision was to balance the mining cycle and to ensure that each crew could be

held accountable for the work required per shift. This required each crew to blast, clean and fully

support 2 ends per shift including the wetcreting of these ends (see Figure 5). Working 12 hour

shifts also reduced man traveling time in the shaft, thereby increasing rock and material hoisting

available time.

Figure 5

Tunnel Dimensions

The size and number of access tunnels in all future deep level mines will mainly depend on

ventilation requirements, such as system pressure losses and acceptable air velocities. This was also

relevant for the Moab project with an area requirement of 16m² per tunnel, which equates to an end

4.4m high x 4.5m wide (see Figure 6).

Tunnel Profiles

FLAC 3D computer modeling done by ITASCA was used to obtain the optimum tunnel profile.

Aspects considered for the various layouts were:

• The optimum shape of the tunnel in quartzite and shales;

• Support requirements for the optimum shape under virgin stress;

• The peak loading sustainable by each support system.

BAR FACE

SHOTCRETE

CLEAN

20 min

90 min

210 min

MARK OFF

END 1

END 2

20 min

50 min

0.5

hr5hr 30 min 5 hr 30 min

0.5

hr

12hr

EXTEND SERVICES

40 minL.H.D. MAINTENANCE

INSTALL PLATFORM

DRILL & INSTALL SUPPORT 90 min

DRILL FACE

CHARGE UP

RE ENTRY

BLAST

45 min

45 min

5 min

30 min

130 min

BAR FACE

SHOTCRETE

CLEAN

20 min

90 min

180 min

MARK OFF 20 min

50 min

EXTEND SERVICES

40 minL.H.D. MAINTENANCE

INSTALL PLATFORM

DRILL & INSTALL SUPPORT 90 min

DRILL FACE

CHARGE UP

RE ENTRY

BLAST

45 min

45 min

5 min

30 min

130 min

6/23

100100

937

1125

210

0

160

0

500 1750 188

762 1300

4500

400

160

02

40

0

440

0

A stress value corresponding to a virgin stress value for a depth of 2 850 m below surface

(93 Level) was used in the modeling. For the five different profiles modeled, rectangular, circular,

elliptical, elliptically arched and circular arched, the ellipse with a width to height ratio of 1.3 was

found to be most favorable profile. For practical reasons the elliptically arched profile was

therefore adopted (see Figure 6).

Figure 6

4.4 x 4.5 Tunnel

7/23

Breaking

Due to the fractured nature of the ground, the decision was made to limit the length of the blast

holes to 2.5m maximum. This eliminated the use of drill rigs both for utilization purposes as well

as cost effectiveness. Protecting machine operators from this environment will be discussed under

support. Due to the size of the required ends, breakaways and holing positions were identified as

potential high risk areas and certain well defined action steps have been put into place to counter

this (see the following).

Holings

Whenever two excavations come to within 20m of holing into one another, one of the ends shall be

stopped. This end will then be examined for misfires and shall have the primary support installed to

within 1m from the face position, with wetcrete being applied right up to the face on both side-walls

and hanging-wall (see Sketch 1).

Sketch 1

Breakaways

All breakaways are blasted according to a specific sequence in order to ensure that minimal blasting

fractures are induced at bull-nose positions (see Sketch 2).

ADVANCING FACE

HOLING POINT

4M

3M

SHOTCRETE UP

TO FACE BEFORE

HOLING

AREA IN WHICH THE PRIMARY

SUPPORT MUST BE REDUCED

TO A 1M DIAMOND PATTERN

4,5 M LONG MECHANICAL ANCHORS

8/23

Sketch 2

Underhand Development Faces

Due to frequent strain bursting occurring on the development faces, decisions were taken to carry

all the faces underhand. This would provide some means of protection for the workers in that the

rock if dislodged would slide down the face and not fall over.

Charging Up and Blast Initiation

Smooth-wall blasting is done using conventional cartridge explosives to charge up the perimeter

holes, and ammonium nitrate based explosives are used on the remaining holes. Conventional fuse

and igniter cord is used in conjunction with the above mentioned explosives. The blast is initiated

by means of battery operated shot exploders from a safe designated blasting point.

Trails conducted with shock tubes over the last three months on one particular level, not only

improved the face advance from 1.7m to 2.2m per blast but also reduced the explosive accessories

cost by R67 per meter. It is envisaged that when the trails have been concluded all development

will then utilize shock tubes.

Support

The depth at which tunneling is taking place has a significant effect on the ground conditions.

Strain bursting which is the sudden release of stored strain energy, close to the face, occurs

frequently when bedding planes with a width of > 1,2m are exposed. The mechanism of failure is

the buckling of the thin slabs created when large bedding planes are exposed (see Photo 1). The

high vertical stress which acts on the thin slab cause it to buckle inwards and results in the sudden

release of the strain energy. Counter measures employed, are de-stressing the face and installing

additional support into the > 1,2m bedding planes.

CROSS CUT

BREAK-AWAY

26 m RADIUS

MINIMUM

2.32.3

3,0

3.6

4.4 5.5

6.8

8.5

1

2 3

4 5

6 7

8

4.5m

9

0 2 4 6 8 10 12 14 16 17,5

10.0

10m

KEY NOTES

•All breakaways must be started according to survey notes

• Drill and blast rounds 2, 3 and 4 concurrently with the advancing face

• Advance the end 10m past the bullnose position

• Drill and blast a 4,5 m wide round into the sidewall at position 1 and support to standard

• Advance rounds 5 to 9 until a straight face is established

• When the breakaway has advanced 10 m install a waterblast

• All survey notes must indicate the frog position of the rail turnout

9/23

By adding construction lines the bulging of the upper sidewall becomes more evident.

Mirror zone

Transition zone Hackled

region

On three occasions large rocks (± 2 tons) were ejected into the excavations, and this necessitated

that the principal decision was made to protect the drilling crews by means of installing wire mesh

on the face, unsupported hanging and sidewall areas.

Photo 1

Photo showing strain bursting

10/23

By means of a vigorous safety campaign “NO ROCK WILL FALL UNCONTROLLED”, fall of

ground accidents were reduced to such extend that no fatal accident has occurred in the last

27 months. The following table illustrates to what extend fall of ground accidents have been

reduced.

F.O.G. 1995 1996 1997 1998 1999

DRESSINGS 77 29 32 2 6

L.T.I. 41 16 9 10 6

S.I.F.R. 25 12 6 3 4

EVENTS 118 45 41 12 12

Note the events include L.T.I. as well as dressing cases.

Making Safe

The Miner will on his initial examination of each working end after barring has been done,

demarcate any geological intrusions with yellow paint. This will serve as his personal signature to

indicate to his workers that he has personally examined the working place.

Temporary Support

This consists of wire-mesh on the unsupported hanging and side-walls secured by means of “Spies

props” and split-sets. The “Spies prop” consists of a 1,5m length of 200mm pipe with a base plate

welded onto it. Suitable slots are cut into the side of the pipe to accommodate the control valve of a

20 ton hydraulic prop inserted into the pipe. A suitable length of 150mm mining pole is then

inserted into the pipe on top of the hydraulic prop is then remotely pressurized to support the mesh

against the hanging-wall (see Sketch 3). The main reason for using these props is that because of

the height of the excavations no suitable mechanical props are available on the market that can give

the required support resistance of 20 tons.

Permanent Support

Due to the fact that wetcrete is carried 12m behind the advancing faces to accommodate the mining

cycle, primary as well as secondary support consisting mainly of 2.9m grouted rockstuds are

installed simultaneously on the advancing faces (see Sketch 4). Quality grouting is of paramount

importance when installing rockstuds and long anchors in deep level mines. Specific members of

each crew are responsible for grouting of support holes. They have been fully trained in all aspects

of grouting, and this enables supervisors to hold specific crew members accountable for quality

work.

11/23

2,0

m

0 ,7 5 m 3 ,6 m U n s u p p o rte d A re a

4,4

m

0 ,5 m

2 ,0 m

Spie

s P

rop

Spie

s P

rop

D r il l P la tfo rm m in . 3 ,0 m f ro m fa c e

W ir e m e s h o v e r la p o f 0 ,2 m

h e ld to g e th e r w ith B e llw ire

0 ,5 m m a x

Wir

e m

esh s

ecure

d to 4

,6m

fro

m face

S e c tio n

P e rm a n e n t S u p p o r t

P L A N K D R IL L IN G P L A T F O R M A N D P O S IT IO N IN G O F

S P IE S P R O P S IN A 4 ,4 M X 4 ,5 M E N D

S lin g E y e b o lt

S a fe ty C h a in

L a d d e r

Underhand face

Sketch 3

Sketch 4

Rock Engineering Training

The need for rock engineering training for Moab Khotsong employees was identified some time

back, as most of the employees had no previous deep level mining experience. All supervisors

therefore had to attend a formal accredited training course. In addition to this an informal “in

house” training course was compiled by the Moab Rock Engineering Department, which was based

on actual accident investigations and local modes of rock failure which was presented to all

Primary Support Standard For 4,4m High and 4,5m Wide

Excavations 1,5m Diamond Pattern

Centr

e L

ine

Section View of 4,4m x 4,5m Excavation

2,9m long, 20mm diameter

full column grouted

rockstuds

Grade Line

4,5m

4,4m

0,75m

NB! : - The two rows of support are offset by 0,75m (See Sidewall View)

2,0m

1,5m

1,5m

0,75m

0,75m

Side wall Vie w of 4,4m x 4,5m Excavation

2,9m long, 20mm diameter

full column grouted

rockstuds

12/23

employees (see Examples 1 – 3). The training also included standards and basic strata control

principals. These standards are dynamic and are updated as new experiences are gained, as we are

pioneering development and sinking in the Klerksdorp area at depths beyond 3 km and cannot gain

any experience from any adjacent mine.

In order to emphasize and create understanding a “Rock Engineering Zero Tolerance Board”

incorporating much of the material used in the informal course is displayed at all waiting places

underground. Models of major geological intersections are also made to create understanding and

to plan the sequence of events in order to traverse the intersection safely.

Example 1

Example 2

PREVENTING STRAIN BURSTING OF SIDE WALLS

BUCKLING OF THIN SLABS

IDENTIFY BEDS GREATER THAN 1,2 M THICK

1,2 M

HIGH VERTICAL STRESS

HIGH VERTICAL STRESS

INSTALL ROCKSTUDS IN THESE BEDS PRIOR TO ALL OTHER SUPPORT

STRAIN BURSTING

ALWAYS WORK UNDER MESH CANOPY

1,2 M

LARGE POTENTIAL FOR STRAIN BURSTING

ZONE OF HIGH STRESS ADJACENT TO FACE PRE - CONDITIONING HOLES MOVE ZONE OF HIGH STRESS FURTHER INTO THE SOLID

PRE - CONDITIONING HOLES

PREVENTING STRAIN BURSTING OF FACE

IDENTIFY BEDS GREATER THAN 1,2 M THICK

FRONT VIEW SHOWING POSITION OF PRE - CONDITIONING HOLES ALTERNATE POSITIONS EVERY DAY

BLAST HOLES

13/23

Example 3

Wetcrete

Strain bursting and rapid deterioration of exposed rock surfaces due to high stress in conjunction

with the dilation of the rock, necessitated the rapid application of wetcrete in current static

conditions as close to the advancing faces as possible. It is anticipated that the current wetcrete

application would suffice in the long- term stability of the access tunnels, and that the need for

meshing and lacing would not be necessary in rehabilitating these excavations in future. This

would be both cost effective and in line with the vision of creating maintenance free access tunnels.

In view of the above decision an underground batch plant which is electronically controlled was

installed on an upper level (see Sketch 5). This batch plant can supply wetcrete to all the

development done on the sub vertical shaft. The wetcrete is supplied via concrete columns installed

in the shaft barrel to the various levels (see Sketch 6).

The supply and demand for wetcrete is done via a voice recorded communication system to ensure

the timeous delivery of wetcrete to the respective levels. On levels equipped with tracks a

trackbound agi – car and loco collects the wetcrete at the station and transports it to the required

area. On trackless levels LHD’s with a receiver bin placed in the bucket (see Photo 2) is used to

transport the wetcrete to the required area. The wetcrete is then tipped directly into the receiver bin

of a high volume concrete pump and then sprayed onto the rock face. Currently the pump is

transported by the LHD to the specific end that needs to be sprayed and this leads to the disruption

of cleaning and drilling cycles. These pumps are costly and are easily damaged by transportation.

Therefore on one specific level the pump has now been installed in a semi–permanent position to

service both ends via pump columns up to a distance of 300m, and is moved forward as the need

arises. The main advantage of this installation is that it is now totally divorced from any other

mining activity, and spraying can now take place as and when required.

1,2 M

1,2 M

DYKE OR FAULT

SHOTCRETE THIS AREA CONCURRENT WITH ADVANCING FACE

BACKLOG

SHOTCRETE

SEQUENCE • APPLY STANDARD SUPPORT UNTIL A GEOLOGICAL FEATURE IS EXPOSED • MAP THE FEATURE & NOTIFY THE GEOLOGIST • DOUBLE SUPPORT THE CONTACTS • SHOTCRETE AN AREA 2M BACK FROM THE FEATURE UP TO THE FACE POSITION • SHOTCRETE CONCURRENT WITH ADVANCE UP TO 2M BEYOND THE FEATURE, MAPPING EVERY DAY • AFTER NEXT ROUND SHOTCRETE BACKLOG UNTIL COMPLETE • LEAVE BOTTOM 1M EXPOSED FOR MAPPING

PREVENTING STRAIN BURSTING AT GEOLOGICAL FEATURES

SHOTCRETE

1M

14/23

Sketch 5

Sketch 6

95 L 100 L 101 L 102 L

85 L

SURFACE BATCH PLANT FOR BULK CONCRETE SUPPLY

MAIN SHAFT COLUMN

TRANSFER PUTZMIESTER LAUNDER RV SHAFT CONCRETE COLUMNS

AGGREGATE STORAGE BINS

TRANSFER BELT

MSD CONCRETE COLUMNS

MOVABLE FEED CHUTE

UNDERGROUND BATCH PLANT

BATCH PLANT

102 LEV.

RECEIVER

WETCRETE TRANSPORT SYSTEM

VERTICAL PLANE

76 LEV.

85 LEV.

95 LEV.

100 LEV.

101 LEV.

KETTLE & 300M

108M

294M

42M

48M

15/23

Photo 2

Wetcrete is applied to within 12m meters from the face after the blast to coincide with the

ventilation standard. Dedicated trained crews apply the shotcrete to the rock faces. The rock face is

barred, properly washed down and all rock-studs are re-tensioned and cut off so that only 100mm

protrude from the rock. This then serves as a thickness indicator that must protrude 50mm when

spraying is completed.

Cleaning

Heat generation from diesel driven LHD’s at depth necessitated the introduction of Electro

Hydraulic LHD’s to clean the access development. Tipping points are established in the connecting

crosscuts that are always within 100m from the face. Tipping takes place directly into 8 ton bottom

discharge hoppers pulled by 8 ton battery loco’s (see Sketch 7).

The two levels developed by means of the mid-shaft loading system are critical for the

establishment of ore reserves. To eliminate any cleaning delays because of scaling due to dog-

earing (see Photo 3) of ore-passes they were supported, and Moab designed wearing blocks were

installed in tap-passes. The vertical ore-passes were supported by means of grouted loops and

shotcrete. The Moab wearing blocks consists of Andesite based concrete blocks and Manganese

grizzly bars cast into slots blasted into the foot-wall of the tap-pass at 4.5m intervals. These blocks

have been very successful to date, and have created “dead boxes” on the foot-wall of the tap-passes

thereby eliminating any further scaling (see Sketch 8).

Ventilation

The twin ends are ventilated with a minimum of 0.3m³/s/m² face area by means of 760mm diameter

force columns only, with all the connecting crosscuts sliped at 45 degree angles to accommodate the

columns within the tipping points (see Sketch 9). Re-entry periods of 30 minutes are maintained.

Closed loop high -pressure cooling cars are installed in connecting crosscuts and are moved forward

as required. These cooling cars ensure an available air temperature of 23.5°C wb at the inlet of the

force fans.

16/23

Sketch 7

Photo 3

TWIN MULTI BLAST ENDS

RETURN AIRWAY

VENTILATION WALL

12m MAX.

FORCE FANS

INTAKE AIRWAY

12m MAX.

SILENCERS

100m OVERHEAD TROLLEY LINE

VENTILATION COLUMNS PERMANENT SERVICE COLUMNS

TEMPORARY SERVICE COLUMNS

9 m MIN. SWITCH GEAR MIN 10 m FROM APEX

TIPPING POINT

17/23

Sketch 8

Construction

Pipe Suspension

Temporary pipe columns consisting of 100mm compressed air, 50mm service water and 50mm

pump columns are suspended at 4.5m intervals next to the ventilation columns by means of

eyebolts, chain and ‘S’ hooks.

Permanent pipes consisting of compressed air, service water, drinking water, pump and chilled

water columns will be suspended on vertical steel bearer sets concreted into the foot-wall.

MMaannggaanneessee GGrriizzzzllyy BBaarrss aass rree--iinnffoorrcciinngg

32 to 38°

Dead-box at the angle

of repose

Angle of influence

0 Hade angle

50 °°

Orepass flow direction

Pinning Steel / pigtail

eyebolts

Andesite Based Concrete

Section AA

A

A

Loops

Re- inforcing

PLAN

18/23

Rail Construction

Semi permanent tracks will be installed 1.6m below grade during the development phase in a

dedicated tramming haulage. The reason for this is that with the limited shaft time available, ballast

cannot be provided to grade the tracks to the final elevation of 1.5m below grade, this can only be

done when deepening of the main shaft is completed. Tracks with an A class rating will be installed

consisting of 30kg rails on 10 ton axle load concrete sleepers with thermal welded joints. In order

to ensure low maintenance on the track installations, drains will be installed 2.1m below grade and

satellite pump stations will be installed to ensure that no mine water comes into contact with the

ballast rock. The top elevation of the temporary roadway is of critical importance for track and

drain installations. The step by step sequence of track installation is shown in sketch 9.

Sketch 9

Cover Drilling

The length of the cover holes have been increased from 120m to 150m, in order to synchronize the

rate of advance of the ends to that of the site preparation and drilling time required for each hole.

To ensure that the ends are always in 20m of cover, instructions and the required sequence of events

are detailed in sketch 10. The purpose of the cover holes is threefold, to provide early warning of

flammable gas and secondly to identify high stress areas in the vicinity of geological intrusions by

means of core sampling. Thirdly to verify geological information obtained through the 3D seismic

survey in order to site tunnels in the best possible position relative to the reef (see Sketch 11).

SLEEPER AND DRAIN INSTALLATION

2.0 m

GRADE LINE SEMI PERMANENT RAIL STAGE 1

ROADWAY FOR L.H.D. CLEANING

1,875 m ROADWAY FOR L.H.D.

AND HOPPER CLEANING

SEMI PERMANENT RAIL STAGE 2 GRADE LINE


1,615 m

1,615 m


DRAIN POSITION RAIL AND KIMBERLY SLEEPERS

19/23

Sketch 10

Sketch 11

COVER DRILLING OF 150M LENGTH HOLES

RETURN AIRWAY

INTAKE AIRWAY

100m

20m

20m

Face position day 6

Hole position day 6

End of previous cover hole

IN ORDER TO ENSURE ENDS ARE ALWAYS WITHIN COVER WITH A 20M OVERLAP THE FOLLOWING PROCEDURE NEEDS TO BE FOLLOWED • ESTABLISH CUBBY 20M PAST THE LAST CON. X/C IN THE RAW

• CLEAN AND SUPPORT CUBBY TO MINE STANDARD

• ADVANCE RAW 6M PAST CUBBY POSITION • DAY 1 RIG DIAMOND DRILL MACHINE AND DRILL AND INSTALL CASING PIPE , ADVANCE RAW 4M / DAY • DAY 2 ONWARDS DRILL COVER HOLE 10M /DAY AND ADVANCE RAW AT 4M / DAY

95

T

IP C

ON

N

X/C

95 TR

AM X

/ C

95 C HLGE 2

Zui

ping

‘E’ F

ault

f

f

Shortcut Fault

f

MB 10 Quartzite

Roodepoort Formation• Quartzite

Roodepoort Formation

• Siltstone

f

Ma

jor

Fa

ult

f

f

Q uartzite Quartzite Siltstone

f

f

f

f

95 Haulage 1

Section

MK

67

MK

75

UCS = 183 Mpa

Tested

UCS = Uniaxial Compressive Strength

UCS = 132 – 291 MPa UCS = 60 – 240 MPa

GEOLOGY 95 LEVELGEOLOGY 95 LEVEL

MULTIPLE

ENDS

20/23

Water Handling

Water control in any tunneling operation is of the utmost importance, therefore proper handling

facilities must be provided at all times. Roadways must be kept dry to minimize tyre wear on

trackless vehicles. Use is made of air driven portable pumps installed in all tunneling faces, from

where the water is pumped via pipe columns to a vertical pump installation. From this position it is

pumped via a satellite pump station to the dams situated at the station.

Sketch 12

MANAGEMENT REVIEW PROCESSES

Safety Campaigns

Various safety campaigns are vigorously management driven in all aspects of the Moab project, and

are revived from time to time as the needs are identified. Examples of some of these campaigns are

listed below and are self-explanatory:

• No rock will fall uncontrolled;

• No equipment or material will be handled un-aided;

• No job is so important that it cannot be done safely;

• Do it right the first time;

• I will make a difference and collectively we will make a success;

• Every person has the right to a healthy retirement.

WATER HANDLING

PUMP INSTALLATION UNDER CONSTRUCTION

PERMANENT PUMP INSTALLATION

AIR DRIVEN PUMPS IN END

2 " PIPE COLUMN TO PERMANENT INSTALLATION

PERM. PUMP COLUMN

NOTE: PERMANENT PUMP INSTALLATIONS WILL BE LEAP-FROGGED

AS SOON AS CONNECTING X/C HAS HOLED.

21/23

Induction

Moab mine being a project with various phases of work that has to be performed, and when these

phases change induction of all employees is of paramount importance to ensure that the work is

carried out safety, on time and within budget. For this reason all the mid shaft development crews

were fully inducted in all aspects of tunneling as described in this paper. Supervisors were

subjected to a written examination of the relevant required standards of work.

Progress Control

Weekly progress meetings are held to monitor specific requirements for the project to ensure that no

delays are caused by inadequate planning, infrastructure or late ordering of equipment.

Monthly pre-planning meetings concentrate more on the work required for the forthcoming month

to meet the set targets, as well as any foreseen requirements or obstacles that can impede progress.

Scrutiny sessions held monthly reviews the performance of each aspect of the project. Detailed

analysis of safety statistics, production achievements and costs are scrutinized and corrective action

implemented where required.

Quality Control

Quality Controllers working directly under the supervision of the Rock Engineering Department,

conduct regular inspections on the quality of grouted support installations and the application of

wetcrete on the rock faces. The support as well as the application of the wetcrete is done by outside

contractors. The Quality Controllers must inspect and verify the quality of the work done during a

measuring month before payment can be made. This ensures that any sub -standard work can be

identified and rectified during the measuring month. Histograms of all the audits are compiled

during each month and presented to Management for identification of the critical few and to take

the necessary action.

Some examples of the histograms are included (see Support Histograms overleaf).

22/23

Histograms

SUPPORT OF BROWS & GEOLOGICAL FEATURES

020406080

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% t

o s

tandard

Visits 10 11 6 7

Actual 52 80 95 80 100 100 100 100 97 95 75 84

Target 100 100 100 100 100 100 100 100 100 100 100 100

Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec

WASHERS PROPERLY SECURED

020406080

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% t

o s

tandard

Visits 10 11 6 7

Actual 75 90 95 79 95 90 100 86 89 88 92 88

Target 100 100 100 100 100 100 100 100 100 100 100 100


CORRECT TYPE & NUMBER OF SUPPORT

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% t

o s

tandard

Visits 10 11 6 7

Actual 53 95 95 78 85 90 90 100 100 90 90 86

Target 100 100 100 100 100 100 100 100 100 100 100 100


HOLES GROUTED

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% to

sta

nd

ard

Visits 10 11 6 7

Actual 90 95 95 95 100 100 100 96 96 91 97 91

Target 100 100 100 100 100 100 100 100 100 100 100 100


PATTERN TO STANDARD

020406080

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% to

sta

nd

ard

Visits 10 11 6 7

Actual 67 98 90 85 95 85 100 98 96 90 90 82

Target 100 100 100 100 100 100 100 100 100 100 100 100


DEMARC. OF BROWS & GEOLOGICAL FEATURES

020406080

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% to

sta

nd

ard

Visits 10 11 6 7

Actual 80 90 95 80 100 100 100 100 100 90 90 80

Target 100 100 100 100 100 100 100 100 100 100 100 100


AREA COVERED WITH TEMPORARY SUPPORT

020406080

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% to

sta

nd

ard

Visits 10 11 6 7

Actual 65 90 95 90 100 95 100 86 93 92 91 92

Target 100 100 100 100 100 100 100 100 100 100 100 100


PULL TESTS

020406080

100120

% t

o s

tandard

Visits 10 11 6 7

Actual 100 100 100 0 0 0 100 0 100 100 0 0

Target 100 100 100 100 100 100 100 100 100 100 100 100


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CONCLUSION

Safety

Considerable success has been achieved in safety through the continuous commitment of

management and all employees, as well as the dynamic standards and work practices employed to

eliminate incidents. For the first time in mining history a sinking project achieved a million fatality

free shifts. In addition to this achievement the Anglogold Chairman’s Shield was won for the last

three consecutive years for the best improvement on the previous year’s Serious Injury Frequency

Rate.

Management realizes that the commitment to eliminate all injuries is a journey and not a

destination, and would therefore require dynamic standards and work practices as well as

continuous awareness and mindset campaigns.

Project Progress

With the initial planning of the production buildup, consideration was given to all the different

aspects of the tunneling operation. As most of the production crews were inexperienced in this type

of mining, a conservative target was set for the first few months which catered for a learning phase

in all aspects of the required work. As experience was gained targets were gradually increased and

achieved by the crews, and the tunneling project is now on schedule.

The main aim of the tunneling project was to deliver a quality developed meter that was aligned

with the 21st century haulage, in that no maintenance would be required to both the excavation as

well as the infrastructure installed.

ACKNOWLEDGEMENTS

The authors would like to thank Anglogold for their permission to publish this paper.

Method of Developing and Equipping a 21st Centaury Haulage ...

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