Willmar tribune. [volume] (Willmar, Minn.) 1895-1931, 1899-02-01
Among the Rockies.


Seventh of q series of letters written
by the editor while on his trip in the
ASPEN, COL, Jan. Is, 100.
While some Of the silver and lead
ore found in this camp IS rich enough
to warrant its mining and transporta-
ton to the smelter, the greater part of
it is so low grade that it would not
pay the transportation and Treatments
charges. In 1893 when the "panic"(?)
para]yzed the silver mining industry
a great many mines shut down. and
none but those persons tied down in
the camp remained here. The death
knell Of the town had evidently sound
ed. and those who remained were bare
ly able to exc out an existence. The
ingenuity Of man overcometh many
obstacles, however, and as the result
of the close application of practical
minds on the problem confronting
them, the concentration idea develop
ed and this camp has now four mills
with an average capacity of $50 tons
Of ore day, which make possible the
working Of mines which otherwise
would be idle. AS the word indicates,
a concentration is a mill in which the
valuable part of the Ore is separated
from the waste. I have visited two of
the works here, the joint mill Of the
Mo'lie Gibson and Argentum-J uniata
mines and the new Smuggler mill.
While the machines differ in con-
struction, the ideas used are the same
in all the mills. The ore, which gen.
orally runs in from four to eight oun-
ces Of silver and perhaps that many
per cent of lead, is first run through a
crusher, which reduces the size of the
rocks to about the size of hickory nuts.
The ore is then automatically fed into
heavy mills, where huge rollers grind
it to the finest dust. A stream of wat
er generally what is pumped from the
mine) flows into each one of these
mills and the ore is carried away by
the water as fast as reduced to size to
admit of its flowing through fifty
mesh screen which closely surrounds
the mill. This water is then led to the
concentration tables or vanners. It
is in the construction and adjustment
of these machines where the ingenuity
Of the inventor has been called into
play. In the Smugeler mill tables
are used. These tables slope gently
downwards and sideways. Slight
creases run lengthwise of the table.
The water from the mills containing
the ore is spread upon the table in an
even sheet from the upper corner. The
table has a vibrating motion which
assists the arresting of the heavier
particles from flowing with the lighter
waste. The metal Or heavier particles
follow the upper side of the table to
the lower end Of the table while the
lighter stuff flows off on the lower
side of the table. Clear water flows
over the lover portion Of the table
which clears away the waste that may
adhere to the particles of metal. The
water which flows Off the table is
caught in three compartments. The
quantity Of which reachse the higher
side of the lower end contains the bulk
of the metal, as may be seen by it's
dark blue color, and is caught and
led to the settling tanks at once, while
the Intermediate grade is caught sep
arate]y and again run over tables on
a lower level. The pure waste which
is Of a light yellow color is led to the
waste-way. The ore that is saved is
dug from the Bottom Of the settling
tanks and dried for shipment. While
the amount varies, the average pro-
portion of the ore saved to that treat
ed is about one to eleven, so that II
tons Of ore yields one ton of concen-
trates. The concentrates yields about
90 per cent lead and from so to Is oun-
ces Of silver to the ton, which have a
market value Of about $84. 1t is es-
timated that this mill saves about 80
per cent of the ore treated, which is
considered a very satisfactory result,
indeed. The other 10 per cent flows
with the tailings to enrich she bottom
of the river. The other mill we visit
ed used different machines. Instead
of tables, it has moving belts of rub
Der upon which the water charged wi tn
ore il dropped.; The belts move up.
wards and the theory is that the
heavy particles follow the rubber sur
face up through the STREAMS Of clear
water while the waste is washed down
the incline. This mill is of recent
erection, but has beeu perfected so as
to save IS per cent Of the value of tie
ore treated. XII
F., The work done BY the mills is au-
tomato and but few men are needed to
operate them, but the breaking Of. the
ore in the mines with which to. feed
r.,