New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1879-08-23
GOLD IN THE BLACK HILLS.
wit.

HANDLING AND LOADING IN THE MINES hhDoOhD
TO MINMUM-ORE IN THE MINES HIGHER
THAN THE LEVEL OF THE MILLs-rHE STAMP
MILIs-doLD PRODUCT OF THE HILLS PER
MONTH.
frRom A STAFF CORRESPONDENT or THE rRIBUSEl
DEADwooD. ID. T., Aug. 81 have said in former
letters that the wonderful development of gold
mining in the Black Hills during the past two
years has been due tine experience and skill when
the great California companies have brought to the
working Of their mines. and the liberal investment
of capital in facilities for taking out and reducing
the ore with the least possible expense In this let
ter it Is my purpose to explain how 1t Is possible 10
mine and mill ore In the Black Hills at cost OF less
than So ton, and in one instance for about ~
ton The ledge or belt of ore, it passes through
the range OF hills nearly in north and south dlrec
tion crops out at the top Of each mountain, ana Is
covered Oh the sides only by thin layer OK Orilt
and sOll. When this is stripped off the VEN Is eA-
posed TO view in the form Of a great quarry Of red
quartz from fifty TO two hundred feet WIDE, ana
bounded on each side by wall of slate ofneary the
same color, standing upon its edge at an angle OF
SO.
This quartz rock. which is oil ore and which may
be blasted ont as easily rough stone for building
or road-makng is obtained in the East, is all sent TO
the mill and crushed without selection and even II
tramways had TO be laid up 10 the face of theqnary
and the ore had TO be loaded upon cars by hand the
expense would not be great, But In most OF the
mines even the cost of handling and loading IS re-
duced TO a minimum in the following manner: In
developing mine it Is customary to construct tun-
nels, some of which cut the vein at right angles
while others follow the general direction OF the
ledge If the tunnel runs the vein, drifts OF
| passace-ways are cut at right angles TO the main
tunnel which, of course, follow the general drec-
ton Of the lode. One of these tunnels. starting at
| point on the side Of the hall nearly level
with the feeders of the stamp mill In
which the ore is to be crushed is driven In directly
beneath the open cut or quarry from which the ore
is to be TAKEN and winze OF shaft from the sur
face of the rock is opened PRECAUTIONARY to the
tunnel tramway leading to the mill is built
into the tunnel, and chutes similar TO those by
which coal Is loaded into cars vessels are built
at the bottom Of the Wine. AS rhe men blast out
the rock or loosen it with their picks they push it
down through the shaft and, being caught by the
chutes it is allowed 10 slide into the cars which are
placed Immediately beneath.
All of the mines on the great belt are worked
by this method. / do not mean to say that none OF
the ore of these great mines has to be loaded
into the cars by hand. The managers of every
mine if they work it properly, develop at
least as much new every month as
they take out. Otherwise the mine might stop pro-
| ducing some month, not because it contained no
ore, but because it not accessible This deyel-
opment is effected by extending or constructing
new tunnels, drifts and cross-cuts, and the ore or
waste that taken out of these has, of course to be
loaded into cars by bond. Some mines, too, take a
| much larger proportion of their ore from the open
| ledge than others. The workings Of the DeadwOod
Nine for instance, for the month Of July were en-
| tirely above ground and all Of the ore taken out
| was delivered IN the cars through Wine such as
! have described. This mine was therefore worked
cheaper than any other in the Black Hills the cost
of mining and milling 1890 tons Of ore
being stated to me at less than $S,000 or cOnsid-
ably less than 81 q ton In other words, the profit
Oh every ton Of ore taken out was than 70.
All of the mines on the great belt have ore
enough IN sight, above the level of their mills, To
last for several wears, with the increased mill
ing facilities that now proposed, so that it will
not be necessary at present to raise any ore through
shafts or inclines. The only workings the belt
now reached by an incline, believe, are in the
Honestake which has an incline down 100 feet be-
low their main level. This has been built more to
ascertain the quality and quantity Of the ore be-
meath than because the rock will be needed in the
near future.
Ali the ores on the belt are of the variety known
"a free mlling that is the PARTICLES Of gold in the
rock are nearly pure and are easily amalgamated
after the rock is crushed. The machinery of a
stamp mill is not very complicated. In the upper
part of It, where the is delivered from the cars,
there are rock-breakers in which the larger pieces
of ore are first broken. The stamps, which consist
of heavy pieces ofiron, shaped something like the
bottom of a mortar-pestle, and called shoes, are
raised about foot by means of a cam working on
a shoulder attached to an upright shaft, and
dropped upon the which is fed beneath them.
Mercury is placed in the battery under the stamps,
and small stream of water constantly runs through
it. AS the rock IS thoroughly puverized. the quick
silver taxes up the PARTICLES of gold contained
il, and part of the anal gam remains IN the bottom
of the battery, while the remainder, with the rock,
which has now become n thin mud Is washed ont
upon the plates IN front OF the stamps Inc plates
sheets of bright copper placed az an incline AS
the water carrying the pulYerlZed rock aud the
analgam passes over them, the latter is attracted
bv the copper and held on ITS surface, while the
former Is carried away TO the ta-dltch. The anal
gam adheres very evenly all over the plates, and
looks exactly like the quicksilver on the back OF
mirror. Once IN two weeks the plates are scraped
of, aud once month the batterIes-the spaces un-
der the stamps-are also cleaned. The amalgam
obtained is formed into balls by hand, and the mer-
curry is separated from the gold by distllatlon In
retOrt. The bullion thus obtained Is cast into
bricks. and is then ready for the market
ore IS reduced much more economically in large
than in small mills. IL requires just as many super
intendents, engineers and fremen, and almost as
many amalgamatOrs and feeders, TO run mill OF 20
stamps as 10 operate one Oh lZO, Wlle Ine lalIcf
will crush six times rs much ore The first mills
erected on the belt were small, and the machinery
of them was mostly of inferior character, so that
the cost of CRUSHING the low-grade ores of these
mines IN them nearly or quite as great as the
value of the gold obtained. The new mills erected
by the California COMPANIES are all arge-each run
ming FROM 60 to 100 stampS-and their machinery
Is Of the best character. 1t has been built to per
form the best work with the greatest economy of
labor. The saving effected IN mining aud milling, |
az have described IN this letter. constitutes the
handsome profit which these mines have yielded TO
their fortunate owners,