52 HISTORY AND DEVELOPMENT OF PLACER-MINING.
pede
of miners and speculators to British Columbia. The subsequent
developments of these gravel fields occasioned loss to those who had
been attracted thither by the desire of gain.
In 1859-60 came the exodus to the Comstock, and in 1862 the rush to Idaho followed.
Hydraulic
mining gained ground steadily from 1852 to 1865. As the river bars and
surface diggings one after another were exhausted, the working of the
old river deposits by the hydraulic process became a necessity. At the
present time it is by this modern method of mining that the bulk of the
gold of this State is produced, and in this business nearly
$100,000,000 of capital are invested.
The
hydraulic process is now carried on upon such a gigantic scale and to
so vast an extent as to require the assistance of the science of
hydraulics and engineering. Heretofore, apart from the construction of
ditches and tunnels necessary for washing the gold-bearing dirt,
engineers have had but little to do with the management of hydraulic
claims.
The
primitive placer-mining of 1852 to 1865 has passed into history.
Forty-inch wrought-iron pipes have been substituted for canvas hose and
stove-pipe, and with the replacing of one-inch streams by a mass of
water discharged through nine-inch nozzles under 450-foot pressure
the last remnants of the early methods disappeared.
