These are 50 in number, 10 having been recently added. The first 40 are
four feet by six feet and four feet deep, the remaining 10 twice as
large. About two tons of burnt ore is put in the small vats (twice as
much in the larger ones), half the vats being tilled at one time, and
then enough cold water is turned in to cover the ore. Steam is then
injected beneath the ore, thus boiling the water. After boiling for some
time, the steam is turned off and the water allowed to go cold. The
water, which after the boiling process turns to a dark red color, is
then drawn off. This water carries the copper in a state of solution.
The ore is then boiled a second time, after which the tank residues are
thrown out and water kept sprinkling over them. This water collects the
copper still left in the residues, and is then run into a reservoir, and
from the reservoirs still further on into settling tanks, previous to