The Columbian. [volume] (Bloomsburg, Pa.) 1866-1910, 1905-05-18
MODERN SEEKER FOR GOLD
His Method Differs From Those
of Old ProSpectors.
DRILL USED IN THE WORK
Great Cost Sometimes Incurred In
Projects Preliminary to Opening
Mine-Chemical Laboratory Car
ried by Pack Animals-Maps
Drawn on the SPOT


Drawn on the Spot.
The yield from the gold mines has
increased 60 per cent in less than a
decade. In seeking the reasons for
this truly remarkable development
one is especially prominent--the great
advance which has been made in the
methods followed by the modern gold
seeker. The prospectors, says the Sci
entific American, have taken advan-
tage of progress in geology, chemistry
and other sciences and have pro-
vided themselves with mechanical aids
which are far superior to the crude
implements employed by the metal
hunters of the past
In the examination of rock for metal
bearing ore, the arrastra of the Mex
leans and Spaniards has been used
extensively, especially in California
and Oregon. This contrivance con-
slsts of a vertical shaft or axis, which
supports several wooden bars fastened
at right angles to it. To the ends of
the bars are attached heavy Hat
stones, which, by the movement of the
axis, revolve in circular pit, a stream
of water is turned upon them and the
arrastra placed in motion by animal
or water power. The ore is resolved
into Shiny sediment by being ground
in the water and passes off through
the sluiceway, which is provided with
rifles for catching the gold.
The modern methods for searching
for desposits of precious metal are so
radically different from those describ-
ed that it may be said a revolution
has taken place in prospecting in the
United States. In the Rocky Mountain
region the formation has been pierced
as far as 1000 feet in the effort to as
certain the existence of a vein.
Among the mechanical appliances
which have been of great assistance
to the modern prospector is the drill
With it he can make borings in a
week where, If shaft were sunk, q
year would be needed. If the forma-
tion Is to be examined by a shaft
however, the cost of sinking it is re-
duced to a minimum by means of ex-
manufactured especially for such SER
vice.
Few expeditions of any size are sent
out without an experienced geologist,
who Is usually provided with maps
and other data giving the best infor
nation available regarding the region
to be explored.
Besides the geologist, the services
of an expert chemist are also of great
importance and laboratory in min
iature is contained in the packs car
ried by the animals. So complete is
this portion of the equipment that a
fairly correct field analysis can be
made of the specimens secured by the
use of the drill or by the other pros
pecting tools. If the outcropping of
quartz vein is discovered, enough
is broken off to allow it's character
to be studied both from a geological
and a chemical standpoint.
After examining it in connection
with the formation in the vicinity, the
geologist is often able to indicate
where the surface can be bored with
the possibility of reaching the ore
bearing stratum at once.
The value of the ore from the out
cropping and that from the interior
can be approximately determined by
the chemist. To crush the ore Is a
slight undertaking, and with the lead
which he has brought along the ma
terial can be readily fused in port
able furnace, In fact, he has the es-
sentials for making "dry assay" on
limited scale. for cupels are now
made Of such light weight that they
can readily be carried on muleback.
In the outfit of the modern pros
pector quicksilver has become prac-
tically indispensable. Its affinity for
gold makes it most valuable agent.
Where the existence of placer gold
Is imagined, the introduction of mer-
curry into the test washer soon solves
the problem and avoids the use of riff
fles and other crude appliances which
were formerly dependent upon almost
entirely. After crushing the specl-
mems of test ore, the quicksilver can
also be used to ascertain the quantity
of free gold among the particles. AS
the mercury can be eliminated by
heating the composition to a sufficient
ly high temperature, it is now utilized
in large quantities by the modern
prospector
Taking the ingot of lead and of pre-
! cious metal he can easily oxidize the
lead by placing it in his cupel and
heating the latter to the required TEN.
perature in an oven constructed Of ma
terial which he can obtain in the vi
cinity. With his nitric acid he sepa.
rates the silver which may remain,
leaving the gold only to be tested for
it's value. The proportion of the golt
! to a given quantity of ore can be de-
termined by his scales, but by using
his touchstone or black basalt he can
detect the quality Of the gold by the
color which this substance makes
when drawn over the surface Of the
| ntoy