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988
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MINERAL RESOURCES.
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In
1911 crude platinum sand was imported into the United States to the
amount of 34,412 ounces. Assummg a content of fine platinum of 80 per
Cent we arrive at the approximate figure of 27,500 ounces of refined
platinum produced in the United States in domestic refineries from
foreign sands.
PRODUCTION FROM GOLD AND COPPER BULLION.
In
calculating the production from bullion there is some difficulty
because of some refineries like that of the United States Mint, the
output of which is in large part derived from secondary sources— that
is, from scrap platinum and from sweepings, etc., bought from jewelers
and dentists. During 1910 private refineries also began the separation
of platinum metals from gold bullion.
According to the best estimate that can be made domestic refineries
f
produced in 1911
about 1,200 fine ounces of platinum from bullion, It is not possible to
differentiate between that derived from domestic and that from foreign
ores. Probably not more than 500 ounces were obtained from bullion
derived from domestic mines.
In
conclusion, the total quantity of refined platinum produced in domestic
refineries would be approximately 29,140 fine ounces, of which only
about 940 ounces, valued at $40,890, were derived from domestic sources
of various kinds. The corresponding estimate in 1910 was 773 ounces,
valued at $25,277.
PRODUCTION OF PLATINUM FROM LODE MINES.
Most
of the platinum recovered is contained in the gold and copper bullion
only in very small quantities, and consequently it is in still smaller
quantities in the original ores, which can therefore not be considered
as platinum ores. During 1911 a shipment of material which may properly
be classed as a copper-platinum-palladium ore was made from the New
Rambler mine, in Wyoming. The quantity recovered was not large compared
to the total production of refined platinum given above, but
nevertheless the shipment constitutes a notable event.
The New Rambler mine, as described by S. F. Emmons,1
is situated in the Medicine Bow Range about 32 miles west of Laramie.
The deposit which mainly contains oxidized copper ores and secondary
covellite is contained in dioritic rock of pre-Cambrian age. The
original form and nature of the deposit could not be determined. H. L.
Wells and S. L. Penfield2 found that sperrylite (arsenide of
platinum) was contained in well-defined crystals in this ore in
association with covellite and pyrite. The occurrence of platinum in
the ore was first announced by Prof. Wilbur C. Knight. It is reported
that the rich ores and concentrates shipped contained about 0.5 ounce
of platinum and 1 ounce of palladium per ton. A secondary concentration
of the platinum metals has doubtless been effected during the oxidation
of the deposits.
According to a statement in the Engineering and Mining Journal,3 some
of the concentrates examined by Ledoux & Co. assayed 14.66 ounces
per ton in platinum and 2.82 ounces in gold. The sample
i
Platinum In copper ores in Wyoming: Bull. U. S. Qeol. Survey No.
213,1903, pp. 94-97. a Am. Jour. Sci., 4th ser., vol. 13,1902, p. 95. a
Eng. and Min. Jour., Mar. 4,1911, p. 460.
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