Evening star., 1951-08-06
Chemical BIoodhounds
Track Down Minerals
Even Minute Deposits
Detected in New Process
By Thomas Z. Henry

Chemical bloodhounds to track down
deposits of rare minerals have been de-
veloped by Geological Survey scientists.
Especially adapted to detect almost
incredibly minute amounts of cobalt,
copper, nickel. lead, silver. tungsten,
molybdenum and zinc in soil or rocks.
they promise to reveal long buried
treasure troves deep in the earth.
During century the surface Of this
country has been rather thoroughly
prospected. There seems little likelihood
of further sensational mineral dis
coverieS there. But these new blood
hound techniques will reach down to
bed rock covered by several hundred
feet Of soil or glacial debris. according
to the Geological Survey announcement.
Silver Most Sensitive.
The techniques for zinc, copper, lead,
nickel and tungsten are so sensitive that
they will detect as little as ten millionths
Of an ounce in an ounce of soil or rock.
A millionth Of an ounce Of molybdenum
can be detected in an ounce of material.
Most sensitive of all is the test for silver.
as two-tenths Of a millionth Of an ounce.
in chemical laboratories The work has
been slow, costly, and has required ex-
pertS, but the new methods can be ap-
piled in the field rapidly and by chemists
with relatively little training.
The bloodhound" idea is based on
the fact that faint traces of minerals
are found within considerable radius
of primary deposits. These traces should
become stronger and stronger as the
prospector approaches the central lode.
In the past, say Geological Survey
chemists, cases have been known
where miners using conventional drill
ing methods have come within six
inches Of valuable ore deposits without
suspecting their presence
Two devices are now available. First
is the chromograph, developed by Rol-
lin z. Stevens and Hubert w. Lakin Of
the survey staff. 1t is a portable ap-
paratuS which is relatively simple to
operate. A worker can cover large areas
in day.
Tests in Water.
The second is a modification of the
colorimetric method well known in labo-
ratories which detects mineral traces in
water from springs or streams and in
mixtures with ordinary water of rock
and soil samples. It is the most deli
cate OF the two. In one test it was able
to detect as little as two-thousands of
an ounce of zinc in million ounces of
rock solution.
Each element, the survey scientists
have found. has its own peculiar geo.
chemical habits" Lead, for example,
sticks pretty closely to it's major masses.
1t is very difficult to detect in soil or
rock few feet away. Zinc, on the con-
trary, wanders far af1eld and traces
can be picked up miles away from the
main deposit. These grow more nota-
BILE as the central mineral deposit is
approached.
A major value of the "bloodhounds,
the survey announces, will be east Of
the Mississippi. The West has been
greatly eroded. Mineral deposits are
most frequently found on the surface.
In the Appalachian region particularly
they are deeply buried under glacial de-
bris.
The extreme sensitivity of the silver
tests is of exceptional value, but not
so much because of the possibilities it
offers of finding new silver veins. Silver
is tracer" Wherever it occurs even
more valuable minerals are likely to oc-
cur. Tests now are being developed for
tin, antimony and arsenic. Both of the
latter are valuable not only in them
selves but because, like silver, they serve
as pathfinders.
The ore "bloodhounds'' sometimes have
strange experiences in new territory.
Hot trails have been known to lead to
farmers trash pile and traces of zinc
from an old bucket have been picked
up in stream water half mile away
Perhaps the most valuable find to
date has been lead concentration, not
previously suspected, from which more
than 10000 tons of lead ore already
have been mined,