The Alaska citizen., 1911-09-04

concerning the value of the ore. he locates his
claim. and begins to prospect it either by sinking
shaft driving tunnel according to the to-
Biography of the country.
A tunnel is cheaper and less laborious than a
shaft, for the latter requires windlass and much
time and work to raise the broken material to the
surface If the tunnel be "crosscut'-that is. a
tunnel to intersect the mineral body at an angle
and must be driven through the country rock the
work of drilling and breaking ground" can be
done much more cheaply and expedtously
than by the sinking OF a shaft vertically through
the same kind of rock.
If the ore proves to be very high in value and
exists in large quantities, the prospector is indie
pendent of capital. for he ship it direct a
smelter he takes it the surface, and
so get money necessary develop his mine.
Except in such unusual instances the prospector
is no better off after he has discovered and To-
Gated his claim" and proved the existence
mineral than he prior TO the discovery, unless
he get the cooperation of capital sell the
property. Until mine is developed and the
blocked the work of mining often be
done profit.
1t is less apparent therefore that to
develop mine and the time insure
the safety of the workings, operations con
Quoted and perforCe must be. with approximately
Geometrical precision The size of block of
varies with the character of the vein and the
wishes of the mine manager, but is usually 100
feet in length and height
As an illustrations let it be assumed that the
is in vertical fssure vein not a perpen-
dicular vein for verticals have a decided
incline "dip'-and that the prospect work
sists of a tunnel driven upon the vein for 200 or
800 feet. The encountered the tunnel
level is driven out, of course, the tunnel is
driven. but the above and below the tunnel
level and beyond the breast of the tunnel remains
uneXplOred As the dimensions OF tunnel
usually four by six feet. the amount of ore ex
racted in this exploratory work depends upon the
size of the vein, but in event is a considerable
quantity. The above the tunnel level may be
developed by putting up raises" 100 feet apart.
and the below may be developed by putting
down "winzes" 100 feet apart and to depth of 100
fee and then connecting them by another tunnel,
or technically a level"
If the discovery tunnel the surface,
ant Typographical conditions did PENN, lower
tunnels to be driven, prospect of the sort de
srrjbed would be developed by sinking a shaft
from the surface and running levels or drifts upon
the vein every 100 feet connected by raises.
Then the various block of ready for
stopping" which is the actual mining of the ore
In STOPPING or breaking down the ore, the miner
is always beneath the body The method OF
stopping depends upon the character of the
The soft oxides and carbonates frequently can be
stopped with a pick. The sulphdes broken
down by drilling and blasting. AS the is
broken down. the "muckers" load it into mine cars,
and the "trammers" push the of the tunnel
to the shaft.
The size of stope varies with the size of the
body. 1t may be large ordinary
room, simply large enough to enable the
miners do their work
Methods of operating mines vary in details
cordng to topography, the character of the
ground" that is say, the formation, whether it
is hard soft, and the physical characteristics
of the deposits. For number of years there
has been constant progress in mining methods
which has resulted in great economies. The ORR
ginal method of developing and operating mine
through working shaft-the most expensive
of all methods, necessitating large outlay for
machinery and power, not only to hoist the
but to pump water and pump air into the
mine. The large of shaft operation have
been reduced in many by the substitution of
electrical power for steam, but the outlay for
aipst no Mo fhn6 Of hat