The weekly miner., 1879-11-11
HE WEEKLY MINER.


We are indebted to the New York Tribune
of October 20th, for the following extracts,
which we take from a letter written by its
staff correspondent, Mr.. q. L.. White, from
Butte, under date of Sept. 29th:
"Butte surpasses every other mining dis
trict have ever visited in the number of its
sleads or lodes. The number of claims al
ready staked out here is estimated by citizens
at from 1000 to 1000. All of these leads ;
| lie between Silver Bow creek on the south
and the top of the foothills at the Alice mine
in Walkerville on the north, within belt Of
country about two miles and half wide.
Let the reader accompany me as we take a
general survey OF this mineral district. And
| first, let us 50 down to the creek where it
| flows through Summit Valley, mile and
half south of the town. Standing on its
banks at point where it would be intersected
by Main street, if that thoroughfare We're
continued, and looking north, we have the
main range of the Rocky Mountains on our
right, eight or ten miles away, steep, rocky,
apparently impossible. Before us the foot
hills rise by gentle slopes, and the city of
Butte stands on sort of bench halfway to
the top. Suppose now trench twenty feet
deep to be dug from the point where we stand
due north through the town on the line of
Main street to the summit of the hills mile
and half above it. That trench would pass
through partially disintegrated granite, and
on an average at least once IN fifty feet would
intersect nearly at right angles quartz lead
containing gold, silver, or "copper" or perhaps
all three.
81 do not mean to say that all of these
leads, one half or even one tenth of them, are
rich enough to be developed into valuable
mines. Comparatively few Of them assay
high enough, OH the surface, to have war;
ranted the expenditure of any work upon them
thus far; but even the ledges that are barren
on the surface are of such character that in
any fully developed mining district their
owners would not be content until they had
prospected them to depth of 200 or 800 feet
and ascertained the character of the deposits
below the wate-line. 1t has been by follow
ing leads like these, barren on the surface
that some of the best mines in the country
have been discovered. Here, hundreds of
the lodges have been uncovered; but, unless
the ore found within few feet of the surface
has been rich enough to pay for working, bet
ter mines have been sought elsewhere.
These ledges lie generally parallel with each
other, vary in width from few inches to -
or IA feet, and dip to the south at an angle of
about go deg.
"Following up the trench, which have
supposed to have been opened through the
camp, we find that among the veins it inter-
sects are the largest and richest bodies of sill
yer ore that have yet been discovered in
Butte, and that, with one or two exceptions,
the developed mines that lie on or near it
have small amount of gold mixed with the
silver in the ore, but little or no copper. This
may be called the silver-gold belt, and, upon
it, or within 1900 feet on either side of it, are
situated all the bonanzas Of the camp. The
ores above the water-line are chiefly free
milling sulphurets of silver, with small streaks
Of galena and oxide and carbonate of man
ganese. The lead and manganese have to be
separated from the milling ores as they have
to be treated by other processes. Below the
watcr-lne the silver is still in the form of
sui phuret, but the ore becomes baser and has
to be roasted and chloridized before 1t can be |
sent to the mill. As a general rule, the ores
in the mines of this middle belt are richer at
the surface than at any other point between
the surface and the Water-line. For example |
in the main Shaft of the Lexington mine, at
the surface the ore assayed $50 ounces of sill |
yer to the ton. From that it gradually grew
poorer until the water was struck at depth
of 100 feet, when it assayed only 25 ounces |
to ton. In the Alice mine, also, the ore
was good at thesurface, and poor at the depth |
of 100 feet.
"One mile east of the belt l have been
describing is line of copper mines which |
promise, when fully developed, to be second |
only in importance to the silver mines of |
Butte. This belt has not been explored |
sufficiently to ascertain whether the number |
OF leads is as great as in the slver-gold |
belt, but number of good veins have been |
opened, and considerable quantities of copper
ore were shipped from these mines last year. |
when the price of copper was higher than it |
now is. The principal difficulty in the way |
of making the copper mines of this camp of
value is the presence of arsenic in |
the ore, which detracts very greatly from the |
marketable quality of the copper. Expert
ments are now being made with view OF
etfecting this separation, and those interested |
in the Butte mines are very confident that |
they will be successful. This problem seems
to be no more difficult than that presented
ten years ago OF making the lead of the Rocky
Mountains equal in quality to that which was
imported. Before 1870, the lead produced west !
OF the Missouri River was pretty poor stuff.
Now, that taken from the silver-lead mines of
Utah, Nevada, and Colorado is equal in quail
ity to that which was formerly imported, and |
has driven the foreign article out of the |
market. The copper veins which have eX-
amlned here are strong and very promising,
though as yet not much developed. The ores |
average about 10 per cent. of copper. There
is at present no way of reducing the ore in
this Territory, but smelter will probably be
erected here within few months
"The surface ores, those above water-line,
are generally free milling, that is, they may
be crushed under stamps, and the silver and
gold amalgamated without any previous treat
ment. Some Of the ores taken from below
water-line may be milled after being roasted
and chloridzed, but those containing oalena
in considerable quantities, manganese, and
copper can only be treated by fire. For the
of the free ores, there are nine mills
in and about Butte, with an aggregate of 1O3 |
stamps, and SIX or seven arastraS. Several of |
the mills treat only ores taken from mines
belonging to their owners, while others are
running almost exclusively on custom ores.
A year ago, the price charged for milling was