The Vein Things of the World ©2010 Dr B. C. Paul Materials in these slides have been organized by...
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The Vein Things of the World ©2010 Dr B. C. Paul Materials in these slides have been organized by the author but many of the facts and images are taken from other sources.
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Transcript of The Vein Things of the World ©2010 Dr B. C. Paul Materials in these slides have been organized by...
The Vein Things of the World
©2010 Dr B. C. Paul
Materials in these slides have been organized by the author but many of the facts and images are taken from other sources.
Vein Minerals
• Fractures and voids in rock masses are available to be filled in by something else
• Often water solutions will precipitate minerals to fill those voids
• Solutions commonly come from 3 places– Water percolating down from the surface– Water forced out of volcanic magma– Water forced out of rocks that are under great
heat and pressure
Where Solutions Get Their Minerals
• They can leach them out of the rocks around them
• They can pick them up from the molten rock mass they come from
• They can pick them up from rock that is being metamorphosed
The Hydrothermal Driver
• Solutions normally pick up minerals when they are hot and then deposit them in vein fillings as they cool down
• Example – The Carlin Trend Gold Deposits of Nevada (about 8% of world gold production)– Water percolated down from the surface– Mantle convection was trying to rip North America
apart under Nevada so the crust was thinning and the Mantle heat was near the surface
– The water heated up – dissolved gold out of granetic rock masses and then deposited dispersed veinlets of gold.
More Drivers
• The Rand in South Africa (about 40% of Worlds Gold Reserves)– About 3 billion years ago before continents were well
developed mantle intrusives rich in gold spewed out in lava flows
– These mantle lava flows became elevated around a basin (the Rand)
• Erosion weathered away other rock and left placer deposits of gold in the basin.
– The gold placers became trapped in new rock deposits that were metamorphosed
Gold
• Gold tends not to react well with other elements– Thus it is very common as native gold
• Native gold metal is usually always loaded up with something else– Silver will almost always be present, but other
things can be there too.
• Gold does form minerals with Tellurium so you do get Gold Telluride minerals
Native Gold
Load in QuartzPlacer Nuggets
Electrum (Gold/Silver)
AuHardness 2.5-3Density 15 to 19.31 depending on purity
Calaverite
AuTe2 43.5% Gold
Color Yellow to Yellowish WhiteHardness 2.5S.G. 9.04Non Fluorescent Non Magentic
Krennerite
AuTe2 43.5% Gold
Color White to Blackish YellowHardness 2.5S.G. 8.53Non Fluorescent Non Magnetic
Sylvanite
(Au,Ag)2Te4 34.4% Gold
Color Yellowish silver white to whiteHardness 1.5-2S.G. 7.9-8.3Non Fluorescent Magnetic after heating
Petzite
Ag3AuTe2 25.4% Gold 41.7% Silver
Color Iron Black to Steel GrayHardness 2.5S.G. 8.92Non Fluorescent Non Magnetic
Native Silver
Ag
Color Silver White, Gray White, GrayHardness 2.5-3S.G. 10-11Non Fluorescent Non Magnetic
Chlorargyrite
AgCl 75.3% Silver
Color Purplish Gray, Green, White, ColorlessHardness 1-1.5S.G. 5.55Non Fluorescent Non Magnetic
Argentite
Ag2S 87.1% Silver
Color Black to Lead GrayHardness 2-2.5S.G. 7.3Non FluorescentNon Magnetic
Acanthite
Ag2S 87.1% Silver
(Low Temperature crystal structureArgentite is high temp structure)Color Lead Gray, Gray, Iron BlackHardness 2-2.5S.G. 7.3Non Fluorescent Non Magnetic
Proustite
Ag3AsS3 65.4% Silver
Color Blood Red, Redish grayHardness 2-2.5S.G. 5.55Non FluorescentNon Magnetic
Hessite
Ag2Te 62.8% Silver
Color Lead Gray, Steel GrayHardness 1.5-2S.G. 7.55Non Fluorescent Non Magnetic
Gold UsesGold Uses
72
7
21
Jew elry/ Art
Electronics
Dental/ Other
Processing Gold
• How coarse is the gold? (and is it in a native state)– Grind the ore– Use shaking tables or gravity concentrators to get
coarse “free milling gold”• If gold is fine an old method is mercury
amalgamation– Gold and mercury form a heavy complex that settles
to the bottom of the reaction vessel– Heating will drive off the mercury and leave the gold– Mercury water pollution makes method unacceptable
in many areas for large scale work.
Method of Choice is Cyanide Leach
Solution
Ground Ore
Heap Leach
Boosting Solution Concentration(If Needed)
Carbon will adsorb gold from cyanide solutions
Can back flush the columns with strong alkali to release the gold back to highGrade solutions
Merrill Crowe Process
Solutions are clarified (crud settled or filtered out). Zinc is added under vacuumAnd the gold precipitates out.
Overcoming Challenges
• Other minerals or Gold in Telluride– Boost cyanide strength– Roast the ore to destroy interfering sulfides
• The Preg Robbing Problem– Carbon in the ore will adsorb the gold back if
you leach it• Roast the ore to destroy the carbon – hope you
have plenty of money• Bubble through Chlorine to destroy the carbon
Carbon in Pulp – Carbon in Leach
Load it with your own activated carbon and suck up the gold right out of theLeach with your own better carbon.
Gold Production and ReservesGold Production and Reserves
0
500
1000
1500
2000
2500
Production Reserves/20
Met
ric
To
nn
es
Other
Uzbekistan
South Africa
Russia
Peru
Papau New Guinea
Mexico
Indonesia
Ghana
China
Chile
Canada
Brazil
Australia
United States
What is Gold Worth?
Gold Value
0
5000
10000
15000
20000
25000
19
00
19
09
19
18
19
27
19
36
19
45
19
54
19
63
19
72
19
81
19
90
19
99
20
08
$2
00
9 p
er
po
un
d
Gold Price
About $5000 to $15000 a pound
Silver Uses
Silver Uses
Coins/ Medals
Electrical / Solders/Biocides
Jewlry/ Silver Ware
Photography
Production and Reserves
Silver Production and Reserves
0
5000
10000
15000
20000
25000
Production Reserves/20
Met
ric
ton
nes
Other
Russia
Poland
Peru
Mexico
China
Chile
Canada
Bolivia
Australia
United States
What is Silver Worth?Silver Price
0
100
200
300
400
500
600
700
800
900
19
00
19
09
19
18
19
27
19
36
19
45
19
54
19
63
19
72
19
81
19
90
19
99
20
08
$2
00
9 p
er
Lb
Silver Price
About $100 to $250 per pound
Tellurium Uses
• A metal alloy to increase machinability without changing electrical resistance– Reduces metal fatigue problems
• Biggest use is in chemicals and catalysts– Vulcanizing, rubber, synthetic fibers
• Electronics and imaging devices• Cadmium and Tellurium based solar cells
may be a coming breakthrough technology– Not a fact yet
Tellurium Processing and Reserves
• When copper is electrorefined elements left behind in the “slimes”– Selenium– Tellurium
• They are byproducts
Tellurium Recovery
• Electrowinning of copper leaves solid residues at the bottom of cells (Copper Anode Slimes)
• The Slimes are Sulfuric Acid Leached– Dissolves residual copper and tellurium
• Iron is added to precipitate copper and tellurium
• Precipitate is leached with caustic soda– Dissolves out the Tellurium
Tellurium Recovery Continued
• Acid is then used to neutralize the caustic solution– Tellurium precipitates as Tellurus Acid
• Re-dissolve the Tellurus Acid with Caustic Soda– Put it in a electrowinning cell and electrowin
Tellurium
What is Tellurium Worth?Tellurium Price
0
20
40
60
80
100
120
1917
1926
1935
1944
1953
1962
1971
1980
1989
1998
2007
$200
9 p
er L
b
Tellurium Price
About $40 to $60 per pound
Arsenic Uses
• About 50% is used as a wood preserving agent – use is declining due to public fear
• A hardening agent in metal alloys
• Added to lead shot
• Pure forms used in gallium arsenide for computer chips and electronics
Arsenopyrite
Massive
Crystalline
FeAsS 46% arsenic
Color Tin white, light steel grayHardness 5S.G. 6.07Non FluorescentMagnetic after heating
Orpiment
As2S3 60.9% Arsenic
Color Lemon Yellow, Brownish Yellow, Orangish YellowHardness 1.5-2S.G. 3.52Non Fluorescent Non Magnetic
Realgar
AsS 70% Arsenic
Color Auro Red Dark Red, Orange YellowHardness 1.5-2S.G. 3.56Non Fluorescent Non Magnetic
Sources of Arsenic
• Usually a coproduct or byproduct• Can roast arsenopyrite for direct
production• Copper often comes with arsenic minerals• Arsenic minerals are markers found with
Gold• Actual arsenic production may follow more
where production takes place than original source
What is Arsenic Worth
Arsenic Price
0
0.5
1
1.5
2
2.5
3
3.5
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
$200
9 p
er L
b
Arsenic Price
Around 50 cents a pound
Mercury Uses
Uses of Mercury
Caustic Soda
Fluorescent Lights /Dental / Other
Cinnabar
HgS 86.2% Mercury
Color Red, Brownish Pink, Brown, can be grayHardness 2-2.5S.G. 8.1Non Fluorescent Non Magnetic
Processing of Mercury
• Cinnabar will sweat mercury and break down on heating
• Is a lot of byproduct recovery from gold operations
Production and Reserves of Mercury
Mercury Production and Reserves
0
200
400
600
800
1,000
1,200
1,400
Production Reserves/50
Met
ric
To
nn
es Other
Peru
Kyrgyzstan
China
US actually has byproduct production and is considered to have a surplus ofMercury from recycle.
What is Mercury Worth?
Mercury Value
0
10
20
30
40
50
60
19
00
19
10
19
20
19
30
19
40
19
50
19
60
19
70
19
80
19
90
20
00
$2
00
9 p
er
Lb
Mercury Value
About $3 to $10 per pound
Antimony UsesAntimony Uses
Flame Retardants
Transportation /Batteries
Chemicals
Ceramics / Glass
Other
Stibnite
Sb2S3 71.7% Antimony
Color Gray, Bluish Gray, BlackHardness 2 S.G. 4.63Non Fluorescent Non Magnetic
Tennantite
(Cu,Fe)12As4S13 20.4% Arsenic, 47.51% Copper
Color Steel Gray, BlackHardness 3.5-4S.G. 4.65Non Fluorescent Non Magnetic
Production and Reserves of Antimony
Antimony Production and Reserves
0.000
50000.000
100000.000
150000.000
200000.000
250000.000
Production Reserves/10
Me
tric
To
nn
es
Other
Thailand
Tajikistan
South Africa
Russia
China
Bolivia
What is Antimony WorthAntimony Value
0
1
2
3
4
5
6
7
8
9
19
00
19
09
19
18
19
27
19
36
19
45
19
54
19
63
19
72
19
81
19
90
19
99
20
08
$2
00
9 p
er
Lb
Antimony Value
About $1 to $3 per pound
Fluorspar Uses
Fluorspar Uses
60
15
15
HF for Flourine Chem
Petroleum Ref
Flux/ Glass/ Enamel
Fluorite
CaF2 48.7% FluorineColor White, Yellow, Green, Red, BlueHardness 4S.G. 3.13Fluorescent Non Magnetic
Processing Fluorite
• Fluorspar can be a direct fluxing agent as a mineral in its own right– Recovered by grinding and floatation– Trick is that there are usually things like
Galena, Sphalerite, and Barite with it• Have to float these sulfides out first• Then have to float fluorspar in heated floation cells
• If acid HF is to be produced for chemicals the Fluorite is treated with sulfuric acid in a reactor
World Production and ReservesFluorspar Production and Reserves
0
1000
2000
3000
4000
5000
6000
Production Reserves/40
Th
ou
san
ds
Met
ric
To
nn
es
Other
Spain
South Africa
Russia
Namibia
Morocco
Mongolia
Mexico
Kenya
China
What is Fluorspar Worth?Fluospar Value
0
0.05
0.1
0.15
0.2
0.25
1900
1911
1922
1933
1944
1955
1966
1977
1988
1999
$2
00
9 p
er
Lb
Fluospar Value
Around 10 to 15 centsPer Pound
