square
leagues. The price of this metal on the spot is $8, or 40 francs, per
pound, while in Paris it generally costs L30 francs to 150 francs.
The
Choco platinum is the purest and best sold in foreign markets, as it
contains from 80 to 85 per cent of pure metal. Its price had already
risen in 1894 to 900 francs, or £36 ($180), per pound. In spite of the
high price it commands in the world's markets, the exploitation of the
potentially rich platinum deposits of Colombia has been so slight that,
as stated by Air. P. P. Demers, the American consul at Barranquilla,
only 661 pounds of it were produced in the Choco in 1905.
The
region in which native Colombian platinum is found in greatest
abundance is in the western department of Cauca, more especially in
the south central and southern districts of the Choco, Barba-coas, and
Supia, between the western foothills of the Cordillera of the Andes and
the Pacific. The entire territory of this Cauca department has been
renowned, from the earliest days of the Spanish conquest, as the
richest of all the mineral-bearing sections of Colombia. From 1654 up
to 1890 the department yielded $137,000,000 in gold of which the Choco
region alone produced $115,000,000, or 84 per cent.
The
most profitable field for the extraction of platinum is on the divide
between the heads of the Atrato and the San Juan rivers, in the Choco
region, around Tado, the San Juan, Condoto, and Iro. This territory is
comprised between latitude 1°, 30' N. and latitude 6° X.—that is, in
the southern and equatorial portion of Colombia. The platinum lies
hidden in the auriferous sands and alluvial deposits of streams fed by
the melting snows of the Andes and flowing westward into the Pacific.
In these districts one finds a zone or layer of gravel, sand, stone,
and various clays, parallel with the horizon and lying within very
narrow limits. The lowest part of this layer lies at about 80 or 100
yards above sea level and the highest at about 800 or 820 yards, and
its thickness is about 720 yards. Higher up or lower down not one grain
of platinum has been found. The farther from the sea the more difficult
the extraction. The breadth of the zone is from 10 to 12 leagues. The
work of many thousands of negroes since their discovery has not
sufficed to exhaust these deposits (superficial). Their wealth is not
invariable; there are rich and poor spots in the zone. From latitude 1°
30' N. the wealth of the deposits gradually falls off; in latitude 1°
X. they are scarcely worked, and on the equator there is no trace of
them left. South of the equator the expressions, " gold or platinum
veins, mines," etc., are never heard.
The
platinum deposits of Colombia are comparatively easily accessible for
international exportation. Most of the platinum extracted is exported
from the Pacific port of Buenaventura, on the Bay of Choco, which is
conveniently reached in a few days by steamers sailing southward from
Panama city. To proceed thence inland to the alluvial deposits bearing
native platinum is not difficult. An alternate route, recommended by
Consul Manning, is to proceed, first, to Cartagena, on the Gulf of
Darien, in northern Colombia, thence south to the head of that gulf and
up the historic Atrato River 400 miles to its source, where it is
separated from the San Juan by such a low and narrow divide that this
route has been regarded as an available one for an interoceanic canal
connecting the Atlantic and
