17·Gold 369 TABLE 17.1.World gold production and reserves in 2001 Production of world Reserves of world Country [tons] production [tons] reserves South Africa 400 15.8 19,000 38 USA 350 13.8 5,600 11.2 Australia 290 11.5 5,000 10 China 185 7.3 1,000 2 Canada 160 6.3 1,500 3 Russia 155 6.1 3.000 6 Peru 140 5.5 200 0.4 Indonesia 120 4.7 1,800 3.6 Others (Ghana 69, 725 28.6 13.000 26 Brazil 52, Colombia 22) World total 2,530 100 50.000 100 Source:Drillbits Tailings,September 2002. teem for gold results,however,from its inertness to environ- mental influences combined with a relatively high reflectivity, which is about 93%in the yellow-red spectral region and 98%in the infrared.The latter property makes gold useful as heat shields for satellites,visors in space suits,and for thin,IR-reflecting films on windows.Because of its relatively high conductivity(71%of that found for copper)and its corrosion resistance,gold is used in large quantities by the electronics industry,for example,for conducting pads and for extremely thin wires which connect computer chips with the pins of headers.Further,gold is used in dental restoration.(Dental alloys contain,for example,85.6% gold,12.7%platinum,0.2%iridium,0.1%rhodium and traces of indium,zinc,titanium,iron,etc.)Fine particles of gold (colloidal gold)mixed with glass produces a deep red color.Gold leaves are green-blue in transmission. Native gold,that is,gold in its pure(unoxidized)state,is widely found on all continents and in all climate zones,albeit often in finest distribution.It appears near igneous rocks,occasionally in combination with silver,selenium,tellurium,or bismuth.Gold- bearing rock formations,that is,gold accumulations in cracks of rocks,called vein deposits or lode deposits,include hydrothermal veins which are associated with quartz and pyrite (fool's gold). It is believed that superheated water dissolved gold in the earth's interior which,after rising to the surface,deposited in cracks of rocks.Another theory proposes that liquid,gold-containing rocks (magma)emerged from great depths of the earth,out of which gold eventually precipitated.Crystals as large as 3 cm in size haveteem for gold results, however, from its inertness to environ￾mental influences combined with a relatively high reflectivity, which is about 93% in the yellow-red spectral region and 98% in the infrared. The latter property makes gold useful as heat shields for satellites, visors in space suits, and for thin, IR-reflecting films on windows. Because of its relatively high conductivity (71% of that found for copper) and its corrosion resistance, gold is used in large quantities by the electronics industry, for example, for conducting pads and for extremely thin wires which connect computer chips with the pins of headers. Further, gold is used in dental restoration. (Dental alloys contain, for example, 85.6% gold, 12.7% platinum, 0.2% iridium, 0.1% rhodium and traces of indium, zinc, titanium, iron, etc.) Fine particles of gold (colloidal gold) mixed with glass produces a deep red color. Gold leaves are green-blue in transmission. Native gold, that is, gold in its pure (unoxidized) state, is widely found on all continents and in all climate zones, albeit often in finest distribution. It appears near igneous rocks, occasionally in combination with silver, selenium, tellurium, or bismuth. Gold￾bearing rock formations, that is, gold accumulations in cracks of rocks, called vein deposits or lode deposits, include hydrothermal veins which are associated with quartz and pyrite (fool’s gold). It is believed that superheated water dissolved gold in the earth’s interior which, after rising to the surface, deposited in cracks of rocks. Another theory proposes that liquid, gold-containing rocks (magma) emerged from great depths of the earth, out of which gold eventually precipitated. Crystals as large as 3 cm in size have 17 • Gold 369 TABLE 17.1. World gold production and reserves in 2001 Production % of world Reserves % of world Country [tons] production [tons] reserves South Africa 400 15.8 19,000 38 USA 350 13.8 5,600 11.2 Australia 290 11.5 5,000 10 China 185 7.3 1,000 2 Canada 160 6.3 1,500 3 Russia 155 6.1 3,000 6 Peru 140 5.5 200 0.4 Indonesia 120 4.7 1,800 3.6 Others (Ghana 69, 725 28.6 13,000 26 Brazil 52, Colombia 22) World total 2,530 100 50,000 100 Source: Drillbits & Tailings, September 2002