PHILIPPINE ISLANDS.
The output of gold in the Philippine Islands from 1907 to 1921, inclusive, has been $12,948,901.
Gold.—The
mine production of gold for 1921 was $1,313,096, against $1,276,561 in
1920, $1,309,722 in 1919, $1,290,000 in 1918, $1,408,161 in 1917,
$1,514,200 in 1916, $1,320,900 in 1915, $1,371,514 in 1914, $868,362 in
1913, and $570,212 in 1912. Siliceous ores produced $1,235,577 and
placers $77,519 in 1921.
The
milling plant of the Benguet Consolidated Mining Co., in the Province
of Luzon, the largest producer of gold in the Philippine Islands, is
described in the Mining and Scientific Press of December 4 and 11,
1920. The ore is cyanided and yields about $15 a ton in gold and
silver. The cost of mining and milling the ore is about $8 a ton.
Another large producer was the Colorado mine, at Aroroy.
Silver.—The
mine production of silver in the Philippine Islands in 1921 was 26,191
ounces and was recovered entirely from gold bullion refined, as no
attempt was made to develop the known deposits of silver ore.
NUMBER OF PRODUCING MINES.
The
following table indicates the number of mines producing gold and silver
in 1921. The placers are those in which the gold and the silver in
natural alloy with the gold and, in a few placers, with platinum also,
are recovered from gravels and sands, whether by hand washing,
sluicing, hydraulicking, drifting (in frozen ground or ancient buried
river channels), or by dredging. The deep mines are those producing
gold and silver (from ores as distinguished from gravels) mainly from
underground workings, including those whose ores are valuable chiefly
for copper, lead, or zinc, but which contribute precious metals as
by-products. In addition to producing mines here enumerated, many
properties were being prospected and developed (though prospecting and
development were less active than usual) without making any output in
1921, and many other mining claims were being held by assessment work
only.
The
enumeration of placer mines is less satisfactory than that of deep
mines, because some of the operations are only temporary and
individually small and because much of the production is made by
transitory miners not regularly working placer ground. The unit so far
as possible is, however, as for deep mines, not the operator, but the
mining claim or group of claims.
