imperiled. The majority of accidents arising from caves have been caused by this style of work.
High Banks.—Where
the banks exceed 150 feet in height it is advisable to wash the deposit
in two benches. At Malakoff and Smartsville single benches have been
used to the limit of 250 feet, and above this double benches.
When
the man at the pipe sees that the bank is about to cave the water
should be immediately turned away from the falling masses ; if the cave
falls upon the water in the ground cut, a rush of d6bris ensues, and in
many instances the men at the pipe have to run for their lives. Such
occurrences, arising either from carelessness or accident, cause a
loss of time and frequently entail damage to the pipe and machines.
Caves, when practicable, are generally made towards evening, the night
shift running them off.
Light.—Locomotive
reflectors or fires of pitch-wood are used to illuminate the banks
during the night. In some large claims electric lights have been
substituted. No doubt the latter would be more generally used were it
not for the cost attendant on their introduction.
Electric Light.—The
electric-light machine used in illuminating the North Bloomfield mine
is of the Brush pattern and nominally of 12,000 candle-power. To run it
requires four horse-power, supplied through a hurdy-gurdy wheel. The
light is used in two lamps.
The
machine, lamps, wire, and connections cost two thousand dollars set up.
It has been in almost constant use for two and a half years, running
from eight to twelve hours each night.
Its running cost per night is:
