, 1900-02-20
LESSON IN MINING.
PROF. FULTON OF THE UNIVERSE
TY CONTRIBUTES AN IN
TERESTING ARTICLE,
Instructions for Estimating the Value
of a Placer Claim-How Cold and
Silver Are Deposited in the Lodes
The Difference Between Veins
and Dykes Described.

prospecting for various metallic and
~non-metallic minerals, that a series of
articles on these subjects may be con-
sidered timely and of interest. Great
misrepresentation exists among people
as regards the occurrence and value
of the various classes of ores, which IS
due probably to the fact that most
men consider the subject one of such
simplicity that everybody can he a
judge without a trace of previous ex-
perience or knowledge.
The minerals most commonly look
ed for can be divided into two classes,
first the metals-gold, silver, platinum,
copper, lead, zinc. iron and tin, etc,
and second, the non-metallic sub
stances, coal, soda, borax, clays, by
draulic limestones, building stones, etc.
The metals gold and silver almost
always occur together, although the
proportion of one to the other may
vary greatly, and in the case of placer
deposits the gold be by far in %prepond-
france. The gold in placer deposits is
of secondary origin, coming in most
cases from the disi%ntegration OF iudes
or veins, the gold on o of its
great weight being collected and con-
centrated locally by the action of
water. Placer deposits are associated
with rivers and streams, although the
riypr NAV 1nnU cinra hove Iisnrnan,,l
n no trace of it as a river is to be
seen. A placer bed generally consists
of a series of beds of sands and gravels,
Of varying thickness and covering a
greater or lesser area. The bed is I'M
derlain at some depths by the bed
rock. The gold may be fine or coarse
and is often very unequally -distribut-
ed through the placer, but is generally
found in the greatest quantity near the
rock, or in the gravel beds distributed
through the placer. 1t is rarely found
associated with the sands.
From these facts it is evident that to
find TIE value of a placer we must go
down to bed rock. This is usually done
by digging a series of small pits at
various intervals over the area down
to the bed rock. The pit is then sam
pied at different places along the depth
and the samples washed in a gold pan.
The relative value of the gravel may
be estimated by the number of colors
or grains of gold, but the approximate
value is difficult to determine this way
unless n has considerable experience.
The best way to determine the actual
value is to weigh roughly the sample
of gravel, then wash it and dry the
gold and black sand etc, from the
washing and have it assayed. giving
the assayer the weight of the original
gravel sample.
For placer deposits which are too
deep for the digging of pits, small
shafts can be sunk, or pod augers or a
similar device used to reach bed rock.
The value of placers is estimated at
so many dollars or cents per cubic
yard. Whether a placer will pay to
work depends on its situation and cir
- r,-
. - 80.
cow ond +, u,uo,Ir .,o,o hm. -
ohsout t. ,bo oo.o 80 A.. -
~. -
whtoh hama oInoaau 49,. uo..,a.-s
TIL aao 49,
.,aoa. -
:. ost,ma.,a-t ~ -
.
- lUu"
-
- ~
a. - ~ -
'
/. Is human nature 10 greatly over
estimate the 'aiue OIL a mineral depos-
80 aoaaa,. - - III.
un., ~ sa,n IT., or :. 49,
nv nits a,s 60 5o :, nnat,an ~.
nov viii no 80 o,t - .ow - -,
niaoor r,nn,nr cor "a = "rhio na.s
fban 70 saw his danosit hoe . v.,,a -,
-