The Montana post. [volume] (Virginia City, Montana Territory [i.e. Mont.]) 1864-1869, 1867-09-21
BIENENG MATTERS.
THE GILLIAN MILL AND FRIEBuRa BARREL
PROCESS.


PROCESS.
A visit TO the mill near Summit, now
under the management cf Col. A. K. Mcclure,
gave me great satisfaction. The crushing
machines is of the kind that has been in use
from the earliest times. It consists of four
Chilian mills, the workmanship of which is of
superior order. The crushing wheels are of
iron instead of stone, as In most mills Of this
character, and are cast hollow in order that
they may be filed with lead. By this arrange
ment great weight Is concentrated in a wheel
of moderate size, and these mills have greater
crushing capacity than any that have hither-
to seen. The capacity of the four mills is
twenty-fOur tons per day. The amalgama-
tion process Is conducted in part in these
crushers. From them it passes over amaIga-
mated copper plates, and if the ores are silver
bearing or carry gold in a condition that
renders IL difficult to save, the tailings are sub
jected to a further treatment, by the Frieburg
process In the rotating barrels. There are
sixteen of these capable, / believe, of receiv-
ing charge of half ton each. Salt is used
In the barrel amalgamation process, but in
order to secure its perfect action the pulver-
lied ore should be roasted with the salt be
fore being introduced into the barrels. This
seems to be the only deficiency IN these works,
and this can easily be supplied. The follow
Ing is full statement of the European modes
of conducting amalgamation with this appar-
atus for the benefit of all whom 1t may CON
cern
The barrel process is limited mostly to sill
yer ores, having large percentage of silver
but these ores must be comparatively free from
base metals. Ores having more than five per
cent of lead or over one per cent OF copper
cannot be worked satisfactorily.
The pulverized ore, which should, If posi-
bic. be crushed dry, is mixed with from four
to eight per cent of common salt, the amount
varying with the proportion of silver present,
and she mixture is subjected to a thorough
roasting In a reverberatory furnace. In order
that the roasting process shall produce its
maximum beneficial effect, the presence of
pyrites is essential, and If the ore itself con-
tains little OF none, it should be obtained from
other sources and added to it One-half ton of
/ roasted ore Is introduced into each barrel, with
/ about three hundred weight of water and from
seventy-fve to one hundred pounds of scrap
/ iron. The barrels are closed and made to re-
volve with q speed of from fifteen to twenty
revolutions per minute for two hours. The
action OF the iron scraps upon the saline ele-
ments of the roasted ore reduces the perchlo-
rides to protochlorides, and prepares the mass
for the introduction of mercury. If the mer-
curry should be added before this change has
been effected that metal would be in part con
verted into calomel and would be lost. After
the two hours treatment without mercury,
! 500 pounds of that metal are introduced and
the barrels again set In motion. The reac
ton OF mercury, iron and chloride OF silver
results In the decomposition of the latter with
the formation of chloride of iron, and per-
feet combination of the silver with mercury.
The temperature of the mass rises considera
bly,, owing to the chemical reaction
After the introduction of the mercury the
rotation of the barrels is kept up from six to
eighteen hours, according to the quality OF
the ore.
This is one of the oldest and most success
full processes of amalgamation, and is pecu-
liarly adapted to class of ores in this vicinity
A. K. Il.