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60
THE MINERAL WEALTH OF BRAZIL
an
analysis reveals 85.5% platinum and varying quantities of osmiridium,
iridium and palladium. The ore of the Fazenda do Condado has a density
of 16.3 and from 73% to 74% platinum, 21.8% palladium and small
quantities of iridium. The heavier minerals which accompany platinum
are magnetite, hematite, rutile, xenotime, monazite, oligiste, zircon,
goid, diamonds, martite, tourmalines, pyrites, disthene and columbite.
In
the Abaete River, platinum occurs in gravel and is associated with
diamonds, gold, magnetite, perovakite, chromite, garnets, rutile.
disthene, limo-nite, pyrites and phosphatic formations. They have a
round, thin disk form, a density of 17.5, 82.8% platinum and traces of
palladium.
The
occurrences of platinum in the alluvium of Minas Gerais are of greater
importance, the most significant being those in the volcanic soil and
rock and basic rock of the Mata da Corda. In Patos, Coromandel and
Carmo da Paranaiba, the former Servigo Geologico do Brasil carried out
some prospects and tests with the following results:
1) — At the Fazenda Cascata in Patos, 0.6 grams of platinum per
metric ton of volcanic soil and 1 gram per metric ton of dia-basic olivine were found;
2) — in Coromandel, the average platinum content for a ton of vol-
canic rock was 0.81 grams and 0.42 grams for a ton of filitos;
3) — in Carmo da Parnaiba, two samples of volcanic soil tested 1.95
and 4.76 grams of platinum per metric ton.
Platinum
also occurs in the northeastern section of the state of Minas Gerais in
the alluvium of several rivers and ravines of the Sao Matheus and
Suaasui Grande basins. Analyses made of hundreds of samples of the
deposits there showed 0.35 grams of platinum per metric ton of gravel.
Imports
of platinum bars, sheets, and wire have been irregular in recent years,
the total in 1937 having been 19 kilos, 8 kilos in 1938, 14 kilos in
1939 and 3 kilos in 1940. Very recent imports are thus little different
in quantity as compared to the average during the 1920-9 decade when
they amounted to 10 kilograms but are considerably less than that of
the 1930-4 quinquennium when they averaged 21 kilograms, it .being
worthy of note that the importation of 63 kilograms in 1934 was the
largest in twenty odd years. The 1935-9 quantity was 24 kilograms. In
1939, the principal sources were the United States and Great Britain,
48% of the total being from the former and 47% from the latter. The
other suppliers were Germany and France. In 1940, the total imports
were from the United States.
In
1939, platinum semi-manufactures which were imported were priced at
22,209 milreis per kilogram (CIF Brazil) as compared to the 21,832
milreis of 1940.
Imports
of platinum manufactures show a similar irregularity and from the 1.4
kilos of 1937, purchases rose to 3.2 kilos in 1938 and decreased to 0.6
kilos in 1939. The United States and Great Britain are also the
principal sources of supply of these manufactures. In 1940, imports
totalled 1.2 kilos, all of which was from the United States.
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