The weekly miner. [volume] (Butte, Mont.) 1878-1881, 1880-05-18
The.Bonanzn Chief Mine, Montana
Editor Engineering and Mining Journal:

Editor Engineering and Mining Journal:
SIR: l have just returned from visit of
nearly two weeks duration, inspecting the
Bonanza Chief, Alta, Custer, North Pacific,
and other mines of the Alta-Montana com
pany. The Bonanza Chief, however, is
another and separate concern from the Alta
Montana, although the management and most
of the stockholders are the same. The
Bonanza Chief mine was located just one year
ago by three old Montana miners, Messrs. o.
I. Boyd. W. A. RAIDER and II. A. Fisk. First
shaft was sunk some % feet deep, OF until
water was struck; then the owners began
stripping the surface off the lead, to find, if
possible, its width and extent. In some places
the ore body came clear to the top Of the
ground in other places, as much as four feet
of waste dirt had to be removed before the
vein was uncovered.
At the time of my visit to the mine, few
days ago, about 80 feet square of the surface
ground had been stripped, and there was no
sign of any walls yet being found. An incline
cut was run through the center of the opening
aud the mine looks more like quarry than a
| gold mine. Wagons or carts can be driven
right into the excavation, loaded, and the ore
hauled to the mill. The quartz is a brown,
jasperized rock, stained with iron, and readily
crumbles to dust when exposed to the atmos-
phere. Streaks of carbonates of copper also
run through the vein, and small specimens cf
| HdllNc copper nave DStIl lOtlnu. All Ille
different kinds of gold quartz carry free gold,
visible to the naked eye Mr. Ernest Grenier,
metallurgist for the Alta-Montana company,
informed me th:.t he took sample from every
three feet square of the stripped ground, so
that every part of the exposed ledge was
represented, and made assays which averaged
$29.97 per ton. A lot of 26 tons of ore crushed
in Captain H. Guyer's gold stamp mill yielded
$5S per ton. Some of the ore, on being ex-
A,,t lao, ~, Il,, tl>n%,
be panned. As much as $3 has been taken
from one pan of decomposed ore.
Milo Courtright, veteran mlllwright oi
Montana, who has been at the mine from a
period dating back to within short time after
its discovery, informed me that the surface
dirt for several hundred feet below the ledge
would pay well for milling as it was thor
oughly impregnated with tree gold.
The flow of water being so great in the
shaft sunk on the lode, the present owrers
concluded to run a tunnel and cut the vein
about 40 feet below the present floor of the
mine, or G1 feet below the surface. An open
cut was run 200 feet, and at the time of my
visit a tunnel was in 23O feet from its mouth,
but lacked about 70 feet Of tapping the ledge.
An open cut is also making, which will strike
the ledge SIX feet below the present floor of
the mine, SO that four horse wagon can be
driven right into the vein, loaded, and the ore
at GuC by tHlS IlCdllo, SCNCIdl
tons can be mined or quarred out ana shov-
eled into the wagon. Mr.. Courtright says
! that two men in the mine can extract enough
ore in ten hours to keep the 20 stamp mill
running "a hours. The ore is so easily broken
that question whether much if any, powder
will be required.
About 400 yards from the mine is the mill,
consisting of 90 horse power engine, 20
600 pound stamps, copper tables for saving
| fran U0ll and SattIarS The min frOn
ten stamps, after passing over the inclined
copper tables, flows into the settler, pro ,ided
! with false bottom, in which supply of
mercury is kept SO as to save portion of tL
| fine gold which escapes anal gamation on the
copper plates. The quartz wagons are pro-
vded with movable bottoms, and dump the
ore in front of the batteries. The mill build
| ing is 4GX53 feet. The stamps and mortars
were furnished by Dayis Il Tatenl, of Helena.
A ditch from neighborlng creek provides a
plentiful supply of water for the mine.
| Located near the mill is the assay and gem
eral office of the company also boarding
house, sleeping-houscs, etc, etc.
! 1t is hard to form any idea of the vastness
and extent Of the Bonanza Chief mine. 1
| have aimed to give correct account Of it as
! it appeared to me- What the character of the
ore will be 40 feet below water, is as yet only
speculation. If the ore at that depth should
prove too base for stamp-lnill treatment, it
! would he more of an advantage than detri-
ment to the owners, as It will undoubtedly
be pyritous iron, and that product the Alta
Montana Company needs as fiuX at its en-
tensive smelling works; and by obtaining it
here it would save II miles additional trans
portation by wagon, as at present it gets its
iron from the keating mine at Radersburg.
One thing that looks favorable tor the ore
being adopted to the free-milling process is,
that the mine is situated III the same forina