The Black Hills union and western stock review. [volume] (Rapid City, S.D.) 1904-19??, 1910-07-01

nsie.hrpi and doubie-hand. In single
..nH each man holds the drill with one
;,Hnd and strikes with the hammer held In
Ne other. At each strike the drill 10
g}esn Il turn to keep the hole clear and
ne drill free. In double-hSnd drilling one
.:,an holds the drill while the second
swings on 1t With a two-handed siedge.
ne work Is fatiguing and the men
''nnxe positions frequently.
fImbering forms an Important branch OF
. foreground mining. Afser each blast
'hr enormous masses OF ovcrhsnging
lnrks. weighing tens of thousands o. tons,
re carefully examined. The loose hould-
= ere care1uily forced down with picks.
ms work requiring quickness OF band
al eye MS we'll rs ability to leap aside
huge masses of boulders thunder to
:nor Of the workings. One false step
ID the worker is II crushed and manGled
..ss beneath tons of rocks. After this
.yt!i has been accomplished timbers are
pod where they will support the threat
"~'ng ceiling ana carefully hrnced to pre-
N"nt snpping. When the strain proves too
;s;aat for the timbsrs to resist they giva
warning by their gradual bullying and
cracking aud more supports are placed to
reinforce them. In many of the mines
supports Of reinforced concrete are com
'"S ihk' hoS hN MY ~ h''N '>'''
greater strain than the timbers and are
imperv!ous to the destroying action of
water and powder fumes. The larger
mines employ regular timbermen. but in
tue smaller properties every miner Is ex-
pected to perform his share of this work.
Every man Is also expected to see that
the overhead bodies of rock are broken
down If they are loosely held. Ordinarily
the loose rock falls Of its own weight af-
ter the blasts have exerted their tremeEd-
Gus forces.
In the lower workings. which are fire.
quently from two thousand to four thou
sand feet below the surface, great flows
Of water are struck and massive pumps
are provided to keep the flow from ris-
Ing and drowning out the property. These
pumps are operated either by water or
electricity and handle thousands of gal
Ions every minute. Sometimes the flow
of water is so large that the pumps are
drowned out and the company forced to
abandon work until more powerful ma
chimes can be installed. Nearly every
mine provides pumps with capacities
largely In excess ot normal requirements
In order to guard against such emek
|gencies. Many of these N raise the
water a thousand feet to an upper level,
where 1t Is received by a second pump
and carried further upwards in Its ANAL
Journey to the outlet. Where water Is
scarce OH the surface, as in many Ne
'vada properties. the streams from the
pumps are gathered into reservoirs near
the mill and used to furnish power to
drive the stamps, conpressors, engines
and other machinery. This IL accom-
plished by pumping the water to storage
reservoirs at a point several hundred feet
high and allowing 1t to fall upon man.
moth water wheels below. Tn power
thus developed is tremendous and Ii the
CHEAPEST known to man.
! From the surface bins the ore Is taken
to rock crushers where 1t Is reduced to
small pieces. the largest about two inches
In size. automatically fed TO the stamps
These are immense pieces Of fashioned
iron or steel weighing from loo to 1,5N
pounds apiece The larger mills contain
from so to 200 stamps. each falling from
a height Of a few inches about 80 time,
a minute. End the terrific blows o.
the stamp the ore IL crushed to a pull
ami much OF the gold caught by the quick
! silver &c 1t passes over the amalRnmatinf