In smaller mining adventures of this description, involving less capital,
large profits have been made in the gold-bearing zone treated of, by also
not having invested in costly canals, which would not have repaid the
latter investment; and thus it is evident that the water companies are
dependent blindly on the prosperity of the miners.
I will now more minutely describe the actual mining operations. The mining
ground being selected, a tunnel is projected from the nearest and most
convenient ravine, so that the starting-point on the bed rock toward the
face of the ravine shall approach the center of the material to be removed
at a gradient of 1 in 10 to 1 in 30. The dimensions of such tunnels are
usually 6 feet in width by 7 in height, and continuing in contact with the
hard river-bed, for the greater ease of excavation, collection of gold,
and conservation of quicksilver amalgam.
These tunnels vary in length from a few hundred feet to a mile, and some
of the longer ones occupying from one to seven years in execution, at a
cost of from 10 to 60 dollars per foot of frontage. The tunnel of the Blue
Gravel Company, with length of 1,358 feet, cost in labor alone 70,000
dollars, but it could now be driven for 35,000 dollars, as skilled labor
is cheaper now than then.
Pages:
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143