The
production of platinum from Colombia is difficult to ascertain. The
quantity imported into the United States in 1911 was 6,371 troy ounces
of the crude sand, valued at $202,611. The total production for the
same year was probably about 12,000 troy ounces.
British Columbia.—The
presence of platinum metals in British Columbia has been known since
1887. The upper branches of Simil-kameen River are known to contain
platinum, especially the North Fork, usually referred to as the
Tulameen River. A considerable
b
production was at one time maintained from these gold and platinum earing placer deposits.1
Camsell estimates the total production of crude platinum from this
district at 9,860 ounces. The richest platinum ground was found on
Tulameen River between the mouths of Slate and Champion creeks. On
Tulameen River no platinum was found above the mouth of Champion Creek,
and below Slate Creek the grains became finer and the quantity
gradually decreased. The platinum in some cases was present in a ratio
of 1 to 3 by weight as compared to gold. During 1911 active prospecting
has been carried on, and it is stated that workable ground has been
discovered. Dredging is the process which it is intended to apply to
the deposit. During the last few years the annual production of
platinum from some of these placers has amounted to only a few ounces.
Statements in the press are to the effect that the depth to bedrock
averages 12 feet. A company organized in Vancouver has leased some 20
miles of Similkameen and Tulameen rivers from the Government. The
production for 1911 is estimated at 30 ounces. Much of the gold and
platinum in this district is coarse and the nuggets have not traveled
far from their original source. Much of the gold is still embedded in
quartz, while the platinum is often associated with chromite, olivine,
and pyroxene. Kemp mentions platinum inter-grown with olivine and
octahedral chromite from the district. One of these specimens shows the
contemporaneous development of the three minerals very clearly. The
rock from which the platinum was derived is probably a belt of basic
intrusives, mainly peridotite, having a flanking border of pyroxenite.
Kemp concluded that the original source of the platinum was in both the
peridotite and the
p
yroxenite, and this
conclusion is corroborated by Camsell. The heavy minerals associated
with platinum, besides those mentioned, are magnetite and native
copper. An analysis of the crude platinum gave, according to G. C.
Hoffman, quoted by Camsell, the following results:
