Tony
You misunderstand me.....
I consider "gangue" to include BOTH the waste product from the ore
dressing, AND the waste material discarded underground. That is to say
it is all the material in the ore other than the mineral being won. I
think there is plenty in the definitions you quote to support my view.
Regards
Keith
-----Original Message-----
From: mining-history [mailto:[log in to unmask]] On Behalf Of
Tony Brewis
Sent: 09 September 2010 10:57 AM
To: [log in to unmask]
Subject: Gangue definition
Keith Nicholl's idea that the word "gangue" refers only to waste rock
discarded underground was of interest to me as, having worked some years
in an underground copper mine in India and then later at the open-cast
Marampa iron ore mine in Sierra Leone, and then in my Mining Magazine
days having visited around 140 mines in some 40 countries, I had never
come across this idea.
Waste rock, I have always thought, is disposed of underground or, in the
case of an open-pit mine, to waste dumps, whereas gangue is that part of
the crude ore delivered to the mill for processing, the plant producing
concentrates containing the valuable minerals, while as much of the
gangue minerals as possible are despatched to the tailings dump or used
as backfill underground.
Intrigued, I have looked in some of my books to see what their
definitions might be.
In Peele's Mining Engineers Handbook, Third Edition, Tenth Printing
(1963), Section 10, page 6, in the article written by Alan. M. Bateman,
Professor of Economic Geology at Yale University, in discussing
Metalliferous Deposits, he says they comprise the Ore Minerals
(metallic) and Gangue Minerals, usually discarded, although some may be
used (he quotes rock gangue as road metal; fluorspar for flux; quartz
for abrasive; calcite for soil dressing). Ore, he says, is a mixture of
ore minerals and gangue, from which metals may be extracted at a profit.
Arthur F. Taggart's Handbook of Mineral Dressing (Sixth printing 1956)
Section 1, Page 1 defines "crude" as a mixture of minerals as they occur
in the earth's crust; "ore" as a solid crude containing a valuable
constituent in such amounts as to constitute a promise of possible
profit in extraction, treatment and sale. The valuable constituent, he
says, is ordinarily called "valuable mineral" or often just "mineral"
while the associated worthless material is called "Gangue".
In "Mineral Processing Technology" 5th Edition (1992) by Barry A. Wills,
at that time Principal Lecturer, Camborne School of Mines, he says on p6
"Most ores are mixtures of extractable minerals and extraneous rocky
material described as gangue".
I find it interesting that two of these books containing definitions of
the word "gangue" are about mineral processing, i.e. what on earth do
you do with the stuff which has been dug out of the mine?? Crude ore,
as delivered to the mill, contains valuable minerals and gangue. What is
disposed of underground is, I would say, waste rock.
Tony Brewis
This email has been scanned for viruses by Netshield MXSweep.
Geotechnics Limited, Registered in England No. 1757790 at The Geotechnical Centre, 203 Torrington Avenue, Tile Hill, Coventry CV4 9AP www.geotechnics.co.uk
|