gold mining by nick o’brien. today’s golden agenda gold gold –facts –history gold mining...
TRANSCRIPT
Today’s Golden Agenda
Gold– Facts– History
Gold Mining– Process– Players
Environmental Impact– Problems
Future– Movements within
industry
Gold
Gold – symbol Au– Comes from Latin
aurum meaning “shining dawn”
Soft and shiny Usually yellow
color– Can be black or
ruby
Golden Properties
79 on Periodic Table– MW 196.96 g/mol– MP 3129 K– Cp 25.418 J/mol K
Most malleable and ductile metal known– 1g can be beaten into a sheet one
square meter/ 1 ounce into 300 ft2
Good conductor of heat and electricity
Not affected by air or most corrosive agents
Easy to alloy with other metals
Golden History
May have been first metal human’s used
3500 BCE Egyptian Jewelry
Mentioned in Old Testament
World’s earliest coinage around 643 BCE in Lydia
Fueled European exploration of the America’s
Primary goal of Alchemists Gold Rushes Formed the basis for a
monetary standard (IMF)
Golden Uses
Jewelry Computers Jet Aircraft Gold (III) chloride is a
catalyst in Organic Chemistry
Gold Isotope AU-198 – cancer treatment
Gold Flake– $1,000 cocktail
Gold Standard Unit of currency was
equivalent to certain weight of gold (in troy ounce)– 1934 $35.00/oz ($1.13/g)– 1959 $518/oz– 2005 $37,831/oz
Open Market Value 1968– Highest 1980 $850/oz– Lowest 1999 $252.90/oz
Bans in US– From 1933 to 1975 private
possession banned Largest Gold reserve in
U.S.– Federal Reserve Bank in
NY
Gold all around
Gold is widely distributed on the earth’s crust at a background level– .03g/1000 kg (0.03 ppm by
weight)– Occasionally as nuggets, but
mostly as small grains Gold in sea water
– .1 to 2 mg/t (0.1 to 2 ppb by weight)
Gold mines
Economic gold extraction – can be achieved from
ore grades as little as 0.5g/1000kg (0.5 ppm)
– Usually open pit mines 1-5 g/1000kg (1-5ppm)
– Underground or hard rock mines at least 3 g/1000kg (3 ppm)
– Gold not visible until 30g/1000 kg (30ppm)
Open Pit
Blasthole Drilling– Pattern of holes
filled with explosives
– The explosives are detonated so it can be loaded with large shovels into haul trucks
Underground Mining
Adit is dug into earth
Surface containing the ore is loaded with explosives and blasted
Loaded into trucks
Backfilled with cement compound
Gold Mining Step 4
Ore and Waste Haulage– Trucks transport
the ore to various areas for processing
– Higher grade ore goes to mills
– Lower grade ores to leach pads
Gold Mining step 5
Heap Leaching– Crushed ore is
placed leach pads where weak cyanide solution percolates down through the ore
Milling and oxidation
The ore is fed into a series of grinding mills where steel balls grind the ore to a fine slurry or powder
Sometimes the slurry is fed through a roaster to get oxidized
Leaching
The slurry is thickened and run through a series of leaching tanks. The gold adheres to the carbon in the tanks.
Gold Mining Step 6
Stripping– The gold is
removes from the carbon by pumping a hot caustic solution through the carbon.
Gold Mining step 7
Electro-winning – Gold-bearing
solution is pumped through electro-winning cells or through a zinc precipitation circuit
– Gold is recovered
Gold Mining Step 8
Smelting– The gold is
melted in a furnace and poured into molds, creating dore’ bars at 60% to 90% gold
Environmental Issues
Cyanide in water– “Toxic Bob” Friedland– Summitville, CO gold
mine 1996 – Leach pad failed– Leaked cyanide and
had 1000 to 2000 lbs of dissolved heavy metals leaving the site daily
– No life in the river for 17 miles
– $200 million federal cleanup
More Environmental Issues Molycorp Molybdenum
Mine– New Mexico– Over 5 years 100 tailings
slurry spills into red river– 8 miles of the red river
dead– Local high schools had to
relocate because of toxic dust clouds
Baia Mare Gold Mine– Romania– 2000 tailings
impoundment dam failed, 130 cubic yards of waste contaminated with cyanide and heavy metals
– 24 locations of drinking water for 2.5 million people disrupted
– Massive fish kill in Tisza River
Future “No Dirty Gold”
Council for Responsible Jewelry Practices– London next January– Release responsible
mining standards for gold and metal mines
– Mostly volunteer audits Who’s joined in
– Zale Corporation (2006)– Tiffany uses gold from a
mine in Utah that doesn’t use cyanide
– Wal-mart is attempting to come up with a certification process
How much gold?
Approximately 1/3 the size of the Washington Monument.
Approximately 1 cube at 20 meters a side.
References http://en.wikipedia.org/wiki/Barrick_Gold_Corporation http://en.wikipedia.org/wiki/Tailings http://en.wikipedia.org/wiki/Gold_mine http://en.wikipedia.org/wiki/Gold_extraction http://en.wikipedia.org/wiki/Placer_mining http://www.bullion.org.za/MiningEducation/Images/GOLDBARS.jpg http://memory.loc.gov/afc/afccc/p000/p046r.jpg http://serc.carleton.edu/research_education/nativelands/ftbelknap/explorationanddevelopment.html http://www.tocqueville.com/images/upload/GoldSupply.gif http://www.acrat.com/DeLeon-SM.jpg http://www.expedition360.com/australia_lessons_science/mine_shaft_sign.jpg http://www.kengerbino.com/images/MoneySupplyGraph.gif http://www.pbs.org/frontlineworld/stories/peru404/images/environmentalchart2.gif http://www.pbs.org/frontlineworld/stories/peru404/environmental.html http://www.responsiblegold.org/codes.asp http://www.webpennys.com/images/new_mined_gold_output.gif http://www.cyanidepoisoning.org/img/map_users_county.gif http://www.cyanidepoisoning.org/pages/gold_mining.asp http://www.sonoraca.com/visitsonora/images/gold_mining.jpg http://img.dailymail.co.uk/i/pix/2007/03_02/GoldMineLM_468x310.jpg http://www.arizonagoldprospectors.org/ http://www.midwestprospector.com/glacialgoldinfo.html http://www.metalinecontactmines.com/pictures/GoldPour.jpg http://www.sikhspectrum.com/092002/gold.htm
References Additional
http://www.indybay.org/uploads/2007/06/23/marinduque.jpg http://money.howstuffworks.com/question213.htm http://maps.howstuffworks.com/gold-coast-overview-map.ht
m http://www.manifold.net/home/full_scrn_lode.png http://www.akmining.com/mine/bignug4.jpg http://www.akmining.com/mine/minclass.htm http://www.panama-guide.com/article.php/200609191646579
98 http://www.newscientist.com/blog/environment/labels/gold%2
0mine%20fred's%20blog.html http://www.msnbc.msn.com/id/8836974/ http://content.answers.com/main/content/wp/en/thumb/b/b0/
290px-Klondike_mining_camp.jpg SME Mining Engineering Handbook, 2nd edition volume 2 Google Images Men’s Journal, Sept 2007 www.newmont.com/en/about/goldmining