Montana oil and mining journal. [volume] (Great Falls, Mont.) 1931-1953, 1936-04-25

all sampling works, custom mills, an
smelters. This sampler Is such that
automatically cuts out a sample
weight one-fifth Of the tonnage led t
the sampler; in other words, 1t re
wolves at a uniform rate of speed TAX
ing the entire stream of ore discharge
i from the conVeyor belt one-fifth O
the time. The number of Vein cutter
used In series is determined by the siz
of the lot; for instance, on q 50-tol
carload. three cutters would be used II
series. The first Of these three wouli
obtain a sample Of lis so tons or II
tons; the second lis 10 tons, or
tons, and the third lis tons or 30
pounds The 300 pound sample repre-
sents the carload and Is taken to thu
cutting floor after crushing without
being cut by the Vein sampler.
Cleanliness here as In all phases Of
sampIing is the watchword. After each
lot is completed, the mill is thoroughly
cleaned and blown out with air.
The Cutting Floor
The cutting floor is equipped with
smooth steel floors for easy cleaning
18-inch Jones rifles with A-inch slots
automatic screens and rolls for finer
crushing. 1t is here that all samples
are brought and are cut to approx
maCely IL 10 IA POUNDS.
On all lots in order to secure more
perfect mix, a procedure called ring
ing" is employed, that Is the material Is
dumped in pile on the floor and two
men starting on opposite sides of the
rial out to form ring. When all of
the material is spread out it Is SHOW
eled to a cone again in the center.
When the cone is complete the two men
slowly walk around the pile again and
level it off to a depth of about six to
eight inches. This procedure is always
done three times before cutting.
After ringing" the coming and quar-
tering operation follows A wooden
cross Is laid flat on the floor and all
material coned over the cross. The men
then slowly walk around the pile and
pull the coned material evenly over the
cross until the pile is spread out to a.
height equivalent to the height of the
cross. Opposite quarters are now dis
carded and this procedure is followed
until three cuts are made, a smaller
cross being used on each cut. The first
cross is II feet square by - inches high,
and the smallest three feet square by
.hree inches high. The size of the cross
first used depends on the size of the
sample.
All cutting from this point is done by
she Jones sample cutter. The Jones
cutter is 10 inches wide with a-inch |
opening for the slots. The sample is cut
'iffle. When material is extremely wet |
t viii not go through the Jones cutter |
70 1t must be dried after the coming and /
Iuartering operation.
The Vein sample as it arrives on the /
cutting floor weighs from 300 to 1000
pounds, depending on the weight of the |
original lot and therefore the number
1f cutters used.
This sample is finely ground through |
4 set of rolls GO mesh) coned and quar- I
5ered three times, cut through a Jones
splitter to a 1914 pound sample and
sent to the bucking room.
If 1t is desired to make q "4X' sam
Die of any lot, the four samples are
started on the first cut of coming and
Iuartering. Each quarter being taken
or the start of new and independent
ample of the lot
The shovel sample is spread out on
he floor and if sticks or tramp iron
re apparent, it is screened through q
Inch screen. All material that does
lot pass through the screen Except
ticks and tramp iron) are crushed
through a set of rolls and made pass
through the screen. This sample Is now
oned and quartered and cut by theI
ones rifle until ready for the buckingI
DOM.
Bucking Room
From this point all samples are treat
d exactly alike The 12-14-poundl
ample is dried on steam table (tem-l
erature 212 degrees F) and then
round through an Engelback pulver-
,er to any fineness desired. On most
amples one hundred mesh Is suf-
cient, but on hi-grade gold ore one
undred fifty mesh is desired.
The sample is next put through a /.
finch cubical mixer, rotated by shafts
,tached to diagonally opposite corners.
fter a thorough mixing the sample
taken out and cut through a 12-inch !
lnes rifle with * Inch openings. The :
rst cut will reduce the 12-14-pound
Imple to 6-7-pound and the 6-7-pound
nipple is cut again to approximately
lree pounds. This ga pound sample
put through the 100 or $50 mesh
reen as the case may be and here is
point that some shippers wonder
bout What happens to the meta1lics
lat may appear on the screen? Now
hen gold occurs in abrasive gangue
ck and even If it occurs in very coarse
articles in most cases it is pulverized
the grinding operations. However,
hen any scales or metallicS do appear
'ated, weighed in grams and milli-
ans on a chemical balance and sep
'ately aSsayed. Having the weight and
say on both pulp sample and metal
IS, the correct assay of the ore is cas-
7 obtained. The shipper gets no sam
e of metallics because the entire