The Black Hills union and western stock review. [volume] (Rapid City, S.D.) 1904-19??, 1906-01-19

sv1y1yvs This mine may be OF interest,"
to. the mining students, especially u 'no
Black Hills, for several reasons.
First. that the country rock is the same
- tho+ of tho great Homestake belt, beng
algonkian schists.
Second. on account Of the great flow OF
water in the mine.
Third, outside Of the Homestake mlnes'
it is the largest and most complete plant IN
the Black Hills.
The first development work was don
twenty years ago, whore a rich outrcropplng
of white quartz was found on the side OF
the hill near the southern border OF Elk
Creek Valley. A small stamp mill was
erected for the purpose Of crushing the sur
face rock, which was quite rich in free gold,
occurring as shot and nuggets lmpeoaeu
in the white quartz.
The ore body is a large saddle shapeo
mass Of quartz enclosedin the metamorpnlc
schists with it's apex striking N 64U..W and
pitching to the southwark at an angle OF ~.
The horizontal section of the quartz body
as exposed on the 200 foot level has the
appearance Of a letter u, with slightly
aaring arms, evidently two veins come to-
gether forming the U. The quartz body is
thickest at the crest. The inclosing schists
and quartz are SO curved as to give the
whole mass the appearance Of q folded tense
at the crest Of a pitching anticlinal fold.
The gold is contained in the quartz, in
which it often appears free but generally
49, % I.A1 E-.Ll. 5000 II - ork:o1oo of n0Iona +4
The quartz. and schists are heavily i'm
pregnated with pyrite, which at the surface
Is completely oxidized. The ore amalga-
mates readily. The metallic sulphides have
not increased in quantity and quality
enough as yet to justify concentration or
Il the cyanidation Of the tailings.
The original. opening on the deposit was
made through an incline, which was sunk
at1the intersection Of the two veins. One
ofSthese veins standing vertical; the other
dipping at about 445o. At the surface the
out-crop was not SO prominent.
The rock inclosing the veins is soft and
loose near the surface, and is favorable to
the passage Of water into the mine work.
b q The incline was abandoned on ac-
count Of the water. A vertical shaft was
sunk in the hanging wall some distance from
the vein to q depth Of 72O feet. It is IL
ia 10 feet in the clear, divided into three
compartments, two for cages. n the other
for pipes al dladders.
The pipe compartment contains 9 SIX
inch compressor air line. smaller pipas
leading to the different slopes and driyss,
There are three independent water
columns homthesurface to the lowest level,
Two being an eight inch column and the
other q ton inch.
ThereSare two steam lines, 9 five inch
line which is covered with asbestos, also
two auxiliary lines Of four inch pipe also
protected by asbestos covering for use in
care of emergency. There is also 9 fifteen
inch galvanized ventilating pipe leading
ansexhaust fan.
Formerly it was necessary to have pump
stations on each level from the 400 foot
down, until the 100 foot.level was opened,
which drained the upperlevels, there being
decided water channel struck at the south
end 81 tho vein on thisslevel.
The principal pumps in use are aSPres-
gcottts duplex, triple expansion, surface con-
densiing pump with cylinders, is inches,
2239iin. md 339in. lOin. pain. ALSO aduplex
SSco,npound condensing Prescott with cylin-
sdears hin. and 26iin. 1Oin. $ 18in. withcon-
denserSS7i 12in. l2in; several minor
having been iscardedw henthe water
Msrrln1lnnnlla ted on helowest level.
sSS d4rteaats sdidRcnllty has been encountered in