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

I amount Is always weighed 10 d ons
sample and the assay determined: nui
the shipper Is notified OF the correction
10 apply 10 the original sample The
| correction Is not always an increase II
values for sometimes when the metal.
lies are all iron 1t win actually de-
crease the value Of the sample.
/ Any tiny pieces Of wood that carry
! through and appear on this screen are
carefully burned and the ashes safted
through the screen.
The 3-4-p0und sample after screen
ing is rolled carefully on an Oil rolling
cloth until thoroughly mixed. Inen the
sample Is put into six sample packets,
each one being cut by the Jones rifle,
and containing from Clio o. depending
on the specific gravity OF the ore, then
sent TO the assay office.
One set Of samples may be taken i'm
mediately by the shipper or his repre-
sentative, three sets sent to the smalter
laboratory and two sets filed away for
the umpire determination In case the
shippers assay and the smelter assay
do not agree within close limits. On
ores where two or more samples are
made the first TX" contains six pack
cts and the remainder five, as only two
are needed for the laboratory on all
but the first sample.
The shipper receives four pulps on
the AK" samples and each TX" should
be separately assayed.
In the East Helena laboratory an
original and duplicate crucible Is run
on each sample by two assayers. Thus
there are four gold and four silver re-
suits to average In determining the
smeIter figure. In the case of q COX"
there are results and on "4xs' there
are is results TO average for the smell
ter ASSAY. No result can be thrown out
IF there Is wide variation the lot is
resampled.
The lead, copper, and the various i'm
purities are analysed by two chemists |
who check results independently and
the average Of these results Is the
smelter analysis. If they do not cheek
closely the sample is reanalyzed and
II still apart the ore is resampIed. A |
close check must be obtained before
the sample is reported.
Check samples and assays are con-
SANITY being made, even though the
original samples check, to insure the
Of the methods employed.
This extra sampling and assaying is
expensive but 1t is necessary both from
he standpoint Of the buyer and seller
n order to arrive at the true va1u-
able metal content of ores and es-
1ecially spotty gold ores.
Under the laws Of the state of Mon
ana, custom mills and shelters are
'equired to retain for a period Of 80
lays following arrival of ore at a
liant. a sample reject equivalent to so
,ounds per ton Of ore received. The
ample reject is always held at East
Helena for 80 days and If the shipper
s dissatisfied with the original saunp-
ing the management Is glad to have
he ore resampled in his presence or
hat Of his representative without extra
barge. Usually much larger sample /
eject than that required by law is !
eld, and on hi-grade ore the entire !
1t is held for 80 days. When a lot is I
settlement viii be made on
ne average Of the two samplings, or !
q the resample If the shipper requests :
his before the reSample is taken. IL
The shipper or his representative 7
lay be present to see the weighing, !
loisturing and Sampling Of his LOT '
-om start TO finish. He may satisfy I
imself with regard to the metaIlics
T scales by witnessing the SCREENING :,
oeratiOn, take his pulp samples with :,
i'm and have them checked by his .
wn assay office or that of a coynmer- T
al assayer, and compare results with :
hose Of the Smelter laboratory. IF the I.
ssllltS check within close limits. the !
lipperS and Sgnelters assays are aver 2
ged In making settlement; If the dis =
'epancy is too wide. sealed pulps are =
mt to umpire mutually agreed upon. :.
he middle of the three results is used y
making final settlement, losing party y
aging the cost of the umpire. =
The management is glad at any time a
receive suggestions or constructive n
iticism in regards to handling of any q
lrticular shipment. The sole desire In n
e sampling operation Is to arrive at
lie true valuable metal content Of the a,
lipment and this it is believed is be- n
g done as near as correct methods. ~
and care make possible. "
al