Elk City mining news. (Elk City, Idaho) 1903-1913, 1905-05-13

were used for the test. The amalgam
contained only O.1O milligram of gold,
indicating a value of only cents in free
gold per ton of tailings. There were
only few specks of pyrite or heavy
concentratable mineral of any kind
surely less than one-tenth of one per
cent. of the ore by weight. The con-
centrates were, accordingly, not saved
but allowed to go in with the tailings.
The sands and shines were separated,
weighed and assayed, giving these re-
suits:
Gold Assay Percent Percent
Product Value by wight Value
Sands. .......$2.80 TIPS CAT
SlimeS....... 5.25 22.25 1913
TOTAL ......................SS ~. on
Hence both sands and shines are val
liable and will need to be worked. A
test in a percolator showed that the
tailings as received-the shines and
sands together leach readily. There
fore it would appear that amalgamation
and concentration are extracting all
that they can, but that the tailings may
probably be treated without difficulty
by cyanidation. AS showing that
small-scale tests agree with mill oper-
ations, | may mention that, on reporting
as above, was informed that they were
already cyaniding the tailings with sue
cess, but had the test made in order to
satisfy themselves that the mill was
doing as we'll as it could before cyanid-
ing.
In testing a lot of sulphurets carry
ing fifty-six ounces of silver. and one
ounce of gold it was found to give an
extraction of only 40 per cent of the
silver and 70 per cent of the gold. Tests
were then made by roasting the concen-
trates in a large, new muffle and smelt-
ing them together in a; graphite crucible
with ore from the same mine carrying
% per cent of sulphuretts, using equal
weights of roasted concentrates and
raw siliceous, sulphide ore. Two thous-
and grams were used for the roasting
test and 500 grams for the smelling
test. 1t was found that there was no
loss of either gold or silver in the roast
ing; that the smelling gave aInatte fall
of Ia per cent. of the weight of the
charge. effecting a concentration of 7
into l, the matte assaying $50 ounces
gold and 2S5 ounces silver, and effecting
a saving, even in the crude work done
in the small crucible, of 96 per cent of
the gold and 81 per cent of the silver.
There are certain general consider
ations which, it seems to me, have never
been stated with sufficient clearness in
the treatment of this subject, and l am
glad to present them to you:
1. The purpose of any test, however
made, is to get information and not to
work ore.
2. Some things about an ore are Just
as well represented and just as evident
or capable of being found out in rep
resentative pound sample as in a mine
full. For example, lots of one to several
carloads are valued on the smelling, in
assaying, of few ounces of ore more
accurately than in any other way.
Within my experience lots of rich ma
terial worth 81, 900 to $4,000 have re-
peatedly been valued with an agreement
satisfactory to all concerned by a smelt-
ing of less than an ounce of the pulp.
Just as the value of ore can be accura-
tely determined by small scale tests, so
can many of its other characteristics.
3. A very wide range of information
can be arranged quickly and cheaply.
4. Ore tests are either mechanical,
as concentration, or chemical, as smelt-
ing tests, in their nature; or they may
partake of both, as in teaching tests.
5. The purpose of a laboratory test,
either of ore or of mill products, should
not be to parallel the mill, to determine
how much some old machinery, perhaps
insufficient in amount, deficient in de-
sign or unskiflfully run, will extract,
but to determine what percentage OF
the values in the ore can be extracted
by the best possible plant.
6. Small scale tests have the advan-
tage that all the details are under ready
control, difficulties of sampling are OBJ
waited or minimized and the Cleanup
can be performed with an accuracy APP
preaching that of chemical analysis.
Only fifty pounds of a representative
sample is sufficient for a.large number
and great variety of tests. The re-