The Anaconda standard. [volume] (Anaconda, Mont.) 1889-1970, 1898-11-30
N THE Garnet DISTRICT
A Serious Problem in Low Grade
Ores.
A MeTALLURGIST NEEDED
Some OF the Problems Which the De-
vsaopmsns - b District Hss
Brought up-Charscter OF
~ o. Deposits.

Special OF the Standard.
Garnet. Nov. 0--Probabiy no other
gold mining district In the Northwest
offers 90 good . Geld OF operation to q
practical and experienced metallurrist
with means to carry on his operations
a. does this district. Without dis
guising the facts II can be said that
the camp has practically reached that
point In its development where the
treatment Of its low grade ores offers
q serious problem-a problem tha un-
I'll practically solved threatens to ma
terially retard the future DEVELOPMENT
and growth OF h district.
The majority Of the ore deposits in
this region are Of such a character that
their practical n economic mining re-
quires that the different grades Of ore
and usually part Of the wall rock shall
be broker q extracted together, thus
putting . low grade product in the
ore bins.
1t is further required that every DOL
lar OF h mineral value Of this low
inal cost or the whole operation will
be q dismal failure. and while there
are perhaps q few mines that can make
q proht by the extravagant system OF
sorting. sacking and shipping their best
ore to distant reduction works. the ma
s)'ss W NV y OodlCH Will HUI AOInII
OF this expense. and any attempt to
operate them on this line will ultimate
~ result In failure. II IL only because
Of the absence of q better method that
the best mines are exhausting their
magnificent mineral resources I'M
shti the product out OF camp.
Thus the field offers science a fortune
II II will introduce a process OF elm
mating the mineral values OF its ores.
but II requires that the method shall
be at once practical and easy while
giving a high per cent. of extraction at
a slight cost.
This article would be incomplete ~
mention was not briefly made of a few
OF the salient features and character
istics OF the ores and ore deposits of
the district.
The gangue rock of most of the veins
Is a Nitrous white quartz, heavily i'm
pregnated with auriferous iron pyrites
and usually carrying copper and lead
in more or less quantities.. Near the
surface the ore deposits are oxidized
and OF a free milling character: this
oxidized lone only extends to a depth
OF about so or 100 feet. At about this
depth the character Of the ore makes
a radical change inc begins to show
its original nature, but stilI gives evil
dence Of having been altered by the
action OF surface elements. The iron
pyrites which occurs In different stages
OF o~xidization is of a brassy color and
Is brittle and decrepitates easily, be-
ing muc softer than the quartz ma
tr1x. a condition that makes concen-
tration a difficult process. In his rome
copper and lead also make their ap-
pearance, the former occurring in the
form of pyrites, soft glance and brittle
gray copper: the latter In the form of
galena running well In gold. The pres
ence Of these I'VE minerals in any
great quantity would defeat any at
tempt to treat the ore by the cyanide
process.
At greater depths. as was demon
strated In the Mammoth mine at CO.
Iona, the minerals OF the ore become
hard and tenacious. while the gangue
ideal concentrating ore. This will
doubtless be the permanent physical
condition of the ore at great depths.
The only attempt to treat the ore
has been made at the Mammoth COM
pany's mill at Coloma and the Mitchell
a Mussisbrod mill at Garnet. At CO.
Iona the oxidized ore vas most sue
cessfully treated. both at the Mann
moth mill and at the Stone a Loomis
mill. by the simple battery and plate
amalgamation: at the Mammoth mill
a saving Of IS per cent. of the assay
value Of the ore was made in the bat
terry and on the plates. The Stone 4
Loomis mill did equally as well. IL not
better. than this. At the Mammoth
mill the cyanide process was introduced
last winter. but for some reason or
other was abandoned. The Mitchell q
Mussigbrod mill at Garnet has treated
oxidixed ore at different times with
more or less success. The III success
was more largely due to the inexperi-
ence Of the mill man than to any ad-
verse physical condition Of III ore.
The simple battery and plate amalga-
nation system in h hands OF compe-
tent workmen In doubtless the best and
cheapest treatment that can be applied
to the low grade oxidixed surface ores.
but unfortunately only a few mines
have q sufficient quantity OF this class
Of ore to Justify the erection of a mill.
Possibly a good custom mill centrally
located would answer to a certain ex-
tent.
But In the treatment Of the ores un-
DERIVING the oxidised zone. the service
of q skilled N experienced metallur-
gist will be required to determine the
proper method. and to such a man.
with the means to operate. the field In
indeed a promising one.