The San Francisco call., 1897-03-07

cal miner in quantity not less than thirteen
cubic feet and should be of true an average
OF the ore in sight as can possibly be obtained.
The broken thirteen cubic feet should then
be conveyed to the place selected for making
the test and with spalling-hammers broken to
the size of macadam stuff, of which, after
thorough mixing, 200 weight representing as
nearly possible an average of the whole
should be taken and placed on piece of can
vas about TWO yards square, in the center OF
which is stamp-die, and then with cobbing-
hammers the 200 weight should be reduced
small enough to pass through a two-fnch rid
die. The die is then removed and the canvas
raised from each side so that the broken
quartz viii be well mixed, from which two
samples of four pounds each can then be
taken
The cobbed four pound samples should
then be passed through Tay ylors hand rock
crusher till it is fine enough to go through
seive with thirty holes to the linear inch, or
finer if considered advisable.
Ta ylor's hand-crusher has many advantages
over the common mortar and pestle-frst in
the rapidity with which 1t will crush the ore
to the desired tneness without the stamping
and grinding action of the mortar and pestle.
by which action so large g proportion of the
gold is laminated and floats away when al
tempts are made to obtain the gold by me-
ehanical assay-washing.
Those conyersant with mining and milling
know that there are three modes of reducing
gold ores, copper, silver, lead and other ores
namely, crushing" stamping and grind
ing" The first is effected by horizontol roll
ers-rock-breakers; the second by stamps; the
third by edge mills, pans, arrsstras and mill
stones.
The great objection to the two latter modes
of reduction in the treatment of gold ores are
the lamination OF the gold, and the produc-
tion, when silver, copper, lead and other ores
are so reduced, OF so large quantity of shines
The various simple appliances employed for
panning out gold and the separation OF it
from pyritic matter and earthly materials are
as follows: First, "fiat shovel" the use OF
which is by Cornish ore-dressers termed "van-
ming" The foreman of the different dressing
floors where copper, lead and tin ores are as
sorted and concentrated for market neces-
sarily evan" with considerable skill. Vanning
is occasionally brought into use in testing for
gold.
seeond-The "pan'' as used by placer miners
and pros pectors. 1t is made out of one piece
of sheetiron, and for washing gravel aud
cleaning up in milling it is superior to any
other uteusil. A small riddle (picking riddle)
similar to those used in asserting lead and
other ores, would greatly assist the operation
of washing small quantities OF gravel. The
earthly matter would be more easily removed
or cleansed than by rubbing the gravel be-
tween the hands. The picking riddle, with
abo1,t eight holes to the linear inch, has two
long handles fixed TO 1t to work it
large tub, partly filed with water, is re-
quired The riddle, with the gravel in it to be
washed, is then immersed in the water. and
by sharp, quick, half-rotary motion the clay
or soil is soon removed from the pebbles or
gravel. What will not pass through the rid
die is then emptied on a table or board, SO
that it can be examined to see if there are
any nuggets or cement that require crush
ing. In estimating the value OF drifting
graver' it is best to do so by the cubic foot,
ard in the absence of sluices to nse the
picking riddle and then 10 wash cut the gold
with q pan. s'In place" the average small
gravel will weigh eighteen cubic feet to the
ION; on the dump twenty-seyen cubic feet.
Third-The "horn spoon" used principally,
l believe, by the Mexican miners and mlllmen
to test the mercury in the different stages OF