PLATINUM-GROUP METALS 



541 



(A recent analysis of chalcopyrite-bearing dump ma- 

 terial by L. T. Riley and O. M. Parker, U.S. Geol. Sur- 

 vey, gives 0.37 ppm Pt and 0.45 ppm Pd.) Analyses 

 by the U.S. Bureau of Mines from samples in the 

 small area immediately surrounding the glory hole 

 of the Copper Hill mine averaged 1.87 percent Cu, 

 0.49 ounce Ag, and 0.005 ounce platinum metals. 

 Other recognized minerals are hematite, magnetite, 

 pyrite, garnet, ankerite, quartz, and fluorite. The 

 ore zone seems to be the result of intense late-stage 

 fracturing and subsequent replacement of the rock 

 with orthoclase and ore minerals, mainly chalcopy- 

 rite, in a highly sericitized and feldspathized 

 porphyry. 



Another chalcopyrite deposit, in a syenite near 

 Cooke City, Mont., contains 0.5 to 10 ppm Pt, 0.15 

 to 3 ppm Pd, and as much as 0.04 ppm Rh (U.S. Geol. 

 Survey, 1971). This deposit also is associated with 

 widespread potassium metasomatism and veining of 

 potassium feldspar. 



The Boss mine, Nevada (Hewett, 1931), is a typi- 

 cal example of the gold-quartz association. (For oth- 

 er examples, see Mertie, 1969.) About 1,000 ounces 

 of platinum metals were recovered from a pipe- 

 shaped gold-copper-quartz deposit in a minor fault 

 zone. 



RESOURCES 



IDENTIFIED AND HYPOTHETICAL RESOURCES 



Identified and hypothetical resources estimates are 

 given in table 112. The numbers of ounces of plati- 

 num-group metals should be viewed with extreme 

 caution and recognized as estimates of order of mag- 

 nitude. Total known and potential platinum-group 

 metal resources obviously must not exceed the total 

 production to date and the amount in the earth's 

 crust. The lower limit is 63,685,000 ounces; the up- 

 per limit, using Poldervaart's (1955) estimated mass 

 of the earth's crust and Mason's (1958) average 

 abundance of platinum-group metals, must be much 

 less than 1.5 xlO^'' ounces. Ageton and Ryan (1970) 

 estimated the world reserves at 424 million ounces — 

 probably a conservative estimate. 



The estimates of subeconomic resources of plati- 

 num-group metals in the concentric zoned ultramafic 

 complexes of Alaska are based on published reserves 

 of 500x10** tons of titaniferous magnetite at the 

 Klukwan deposit (averaging 0.0027 oz per ton plati- 

 num metals) and 500x10'' tons of titaniferous mag- 

 netite at the Snettisham deposit (average 0.0027 oz 

 per ton platinum metals) . Additional areas of titani- 

 ferous magnetite associated with both of the bodies 

 have a total potential of 3.5x10" tons (averaging 

 0.0027 oz per ton platinum metals) . 



Table 112. — Identified, hypothetical, and speculative resources 

 of platinum-group metals, in million troy ounces 



IDENTIFIED RESOURCES' 

 Summary data from Ageton and Ryan (1970) 



World (total) 424 



United States (total) 3 



Goodnews Bay, Alaska .3 



Salt Chuck, Alaska .012 



South Africa 200 



U.S.S.R. 200 



Canada 16 



Colombia 5 



Data from various sources 



Alaska : 



Snettisham 



Klukwan 



Goodnews Bay 



Lodes 1.3 



Bays B.O 



Beaches .5 



Lituya Bay beaches 



Gold placers 



Porphyry copper 



Copper deposits 



Montana, Stillwater Complex: 



Basal zone 



Chromites 



California, Tertiary gravels 



Western United States, porphyry copper 



United States, minor occurrences 



South Africa, Bushveld Complex 



Rhodesia, Great Dyke 



South Africa. Witwatersrand 



4.55 

 7.55 

 6.8 



.06 

 .016 

 .06 

 .002 



2.4 

 2.2 

 .008 

 ^002 

 .002 

 656 

 '100 

 \075 



HYPOTHETICAL RESOURCES ' 



150 



.15 

 .032 



Alaska : 



Concentric complexes 



Porphyry copper 



Gold deposits 



Montana, Stillwater Complex: Basal zone - 



Conterminous United States: 



Gold placers 



Chromite deposits, excluding Stillwater 

 Complex 



.057 

 .002 



SPECULATIVE RESOURCES' 



Alaska: 



Continental shelf 



Kenai-Chugach ultramafic belt 



Fairbanks-Livingood ultrafafic belt _ 

 Southeastern Alaska ultramafic belt 



Porphyry copper, Alaska Range 



Alkalic rocks, Seward Peninsula 



California-Oregon-Washington : 



Continental shelf 



Beaches 



Antarctica, Dufek intrusive 



Brazil, Goias serpentine belt 



Worldwide : 



Syenitic and alkalic rocks 



Basaltic rocks 



^ Identified resources: Specific, identified mineral deposits that may or 

 may not be evaluated as to extent and grade, and whose contained min- 

 erals may or may not be profitably recoverable with present technology, 



= From Ageton and Ryan (1970). 



"Based on Ageton's (1970) reserve estimates of gold for South Africa 

 and on Cousins' (1972) ratio of osmiridium to gold produced. 



* Hypothetical resources: Undiscovered mineral deposits, whether of re- 

 coverable or subeconomic grade, that are geologically predictable as 

 existing in known distiicts. 



'■ Speculative resources: Undiscovered mineral deposits, whether of re- 

 coverable or subeconomic grade, that may exist in unknown districts or 

 in unrecognized or unconventional form. 



