The Wallace miner. [volume] (Wallace, Idaho) 1907-current, 1913-05-29
ENRICHMENT OF ORES
FOR THE USE OF NAN
NATURES PROCESSES DEscRIe.
Ed IN REPORT ~ v. s. GEO.
LOGICAL SURVEY.

\ AS originally deposited. deep in the
rocks, many of the familiar metals
especially copper, lead, zinc, silver and
quicksilver. exist as sulphides is
as minerals composed Of one or more
metals chemically combined with sui
phur. In such original or primary de-
posts the generally worthless iron
sulphide. pyrite. is likely to predomin-
ate. while the more valuable metals
may be present in quantities too small
to be profitably extracted.
Action o. tho Elements.
In the course of geologic ages. how
ever, as the land wears down under
the ceaseless attack Of weather and
running water. the primary ore de
post, with its small proportion of
valuable metals, is itself exposed to
the forces of disintegration and decay
that are operating over all land sur
faces on the globe. Some constituents
of the disintcgrating ore are carried
away in streams; some are blown
away by winds; and Others particu-
larly some Of the metals, are dissolved
and carried by percolating rain wa
ter down into the earth These metal
charged solutions, coming into con-
tact with the sulphide minerals In the
rocks. have the chemical property OF
Transforming these sulphides into
others more valuable to man. Thus
solutions carrying copper and coming
into contact with pyrite, which is a
mineral compound of sulphur and iron
abstract some Of the iron and leave
copper In its place. The bright vel
low, beautiful but generally useless
pyrite may be changed, for example
to the less brilliant dark gray but far
more valuable mineral chalcocite,
sulphde of copper. This natural
chemical concentration. whereby, az
the exposed upper portion of an ore
body decays and is removed by ero-
sion, it's valuable constituents are in
large part carried down and added to
the portion that remains, IL an excep-
tionally important process and one
that has PLAYED an essential part in
the formation of many large and
highly productive bodies of ore
Investigations by American Biologists
Growing recognition of the over
whelming Importance of enrichment
in the formation of some of the larg-
est copper deposits in the world dates
from the year 1900 and is due chiefly
to the work of American biologists. A
recent publication of the U. S. geologi-
cal survey (bulletin $500 entitled 1.-The
Enrichment of Sulphide Ores" by w.
II. Emmons, is devoted to the descrip-
ton and discussion of this process.
The volume, which is intended to
bring together all the information at
present available on downward sui
phide enrichment Is Invisible into two
various conditions, such as climate
and porosity of the rocks, that influ-
ence the process and with the physical
and chemical principles involved. The
able knowledge of North American
mining districts in so far as this
knowledge bears on the problems of
enrichment. The chemistry of enrich
ment is very fully discussed in connec-
ton with the various minerals found
in ore deposits and the students Of
ore deposition will find the book in
valuable as summary Of what Is
known on the particular subject treat
ed and as guide to the literature
that relates to it,
Valuable Report Can Be Had Free.
The present publication, like Clark's
Data of Geochemistry." bulletin 491
of the U. s. geological survey, Illus
trates the effort now being made by
the Survey to bring together, for con-
venient reference by busy men. data
now scattered not only through it's
own reports but in other publications
also Such volumes, however. are not
mere compilations, The previously
published material Is enriched bv new
observations and Is Illuminated by
in the light of the lates'
scientific knowledge.
"The Enrichment of Sulphide Ores |
bulletin 500. may be obtained free or
application to the director, United |
States geological survey. Washington |
u. G., The demand for the second edl
ton of THE Data of Geochemistry' !
has been so great that 1t was reprinted !
last year and the reprint has recent, |
become exhausted. Another edition
will be issued by the survey during
he present year.
attitudes more properties In what is
Known as the "Crater" section will be
working William Frank leaves this