The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1917-09-13
worked out experimentally before be-
ing tried on the plant.

The practical operation of the pro-
cesses using more than l per cent of
oil has been found to follow, in the
plant, pretty close upon the data OBJ
tanned in experimental work. Per-
haps one Of the first things found out
when the larger quantity of oil was
used was that. although satisfactory
percentage of extractions of the min
eral in the ore could be obtained, a
varying proportion of gangue was also
| floated, resulting In concentrates Of
Considerably lower grade. While at
tempting by manipulation to correct
this difficulty, many operators found
that their extraction percentage de-
clined, and 1t then became a problem
Of the balancing Of mechanical opera
tons so as to secure, at the same time,
satisfactory high extractions and sat
isfactorily clean concentrates.
The additional oil used will natur-
ally be closely limited to the cheapest
obtainable grades, but the scarcity of
oil and the difficulties Of transporta-
ton have led to the use of almost any
oil that could be obtained whatever
its cost. This has led to difficulties In
many cases, and 1t was found that the
quantity of the higher grade oils used,
such as the pine oils and creosotes, in
had to be varied. A few operators
found that the amount of the veget-
able oils, without reference to the
percentage In the oil mixture, could be
considerably decreased when using the
larger percentage, while in other in
stances it was found that the percent
ages Of the higher priced oils had to
be maintained constant, thus increas-
ing largely the amount of these oils
used in the mixture.
AS has been noted in the comment
on experimental operations, the meth
cd of adding the oil has been subject
ed to considerable change, and it has
frequently been found advisable to
mix the oil with water previous to Its
addition to the pulp to be floated. This
process is usually referred to in prac
teal operations as emulsifcation, but
one may we'll reserve judgment as to
whether 1t is really that or not This
one point has made more difference,
perhaps than any other single one in
the change from small to large quaint
ties of oil, and it has almost always
been found Of advantage.
The Records Of the Plants.
In examining the records of plants
in which oil in quantity greater than
per cent upon the dry weight of the
ore being treated is used, one Of the
most striking features is the constant
and regular progression from poor re-
suits, obtained when the larger guam
tity of oil was first put into the pulp,
to better and better results, increas
ing in both the point of percentage ,ex-
traction and grade of concentrates OBJ
tanned, as more experience was gain
ed in the manipulation Of the process.
In almost all cases the greatest re-
larger quantity of Oil were better than
the first results obtained by the use Of
oil less than / per cent when the pro-
cess was first applied in the plant. AL
obtained by the less than l per cent
process, 1t Is better than the first re-
suits obtained, and the results have
been increasing in value constantly
thereafter. While in most cases the
results of the use of the larger guam
tity Of oil have not yet reached the
height of perfection obtained when the
smaller quantity Of oil is used, still, in
few instances the results have been
even better.
| In one plant where 1t was necessary
to use very dirty water containing a
considerable amount of floating shines
the use of the larger quantity Of oil
Immediately produced much better re-
suits as regards extraction percentage
without any diminution Of the con-
centrate grade. In another instance,
fwhere the operation consisted princi-
pally of the cleaning of low grade
gravity concentration product, the ex-
traction results have improved be-
tween and per cent and the grade
of the product was raised about l per
cent. On another large plant the use
OF the larger quantity Of OIL princi-
pally low grade, cheap product,
brought a considerable reduction in
the amount of the higher priced oils
used, such as the pine oils and creo-
sote, this saving going long way to-
ward making up the difference caused
| by the additional cost of the low grade
OIL
The cost of the operation, while not
constituting actually a part Of the
question under consideration, has re-
ceived considerable attention, natur-
ally, from the operators attacking the
problem. Only in few cases, appar-
emily, has it been possible to diminish
the cost Of the process in which the
larger quantities of oil are used, to a
point equal to or lower than the cost
obtained when using the smaller guam :
tity Of oil. 1t has been done in some
cases. but in general the costs have
been higher.