Back in April, 2000, a search was being made for a description of the
Edwards Pyrite & Ore Reduction Co. process as used in Western Australia. I
only just now came across the search in reading through the various postings.
By now the search may have been completed, but following is some useful
information from an old reference that may be hard to find.
The book is entitled Gold Mining and Milling in Western Australia, by
A.G. Charleton, published by Spon in London in 1903. The book is full of
descriptions and flow sheets. In the section on the Great Boulder Sulfide
Works (page 332 ff) a photo appears of a series of Edwards roasting furnaces
under construction. I've seen these described elsewhere (Eissler, Metallurgy
of Gold, 5th edition, 1900, page 306 ff for example has several drawings).
It also seems to me the Jackling furnaces used at Mercur in Utah in the
1890's were an adaptation of this design. Such mechanical roasters are
summarized in Liddell, Handbook of Non-Ferrous Metallurgy, 1st. edition
(1926), page 310 and 315. James does not have much.
In any case, the book in hand is a pretty good source. The description
and photos were taken from the Colonial Mining News of May 1, 1902, as well
as the July, August and September 1902 Reports of the Chamber of Mines of
Western Australia. The process is applied to sulfide ores, wherein the gold
is refractory until the sulfides have been roasted.
Basically they are long rectangular box girder furnaces. The ore was
moved and stirred by rotating rabbles, located along the length and the whole
assemble could be tilted about a central pivot point using screw jacks at the
discharge end. The rabbles rotated alternatively in opposite directions,
there being say 15 in a furnace 64 feet long by 6ft 6in wide. Capacity was
12 tons/day fired with wood, or 15-17 tpd fired with gas. At Great Boulder,
after roasting, the ore was treated by pan amalgamation and then the cyanide
process.
Three other plants are described, one at the Kalgurli Sulphide Works (p.
354), one at the Golden Horseshoe Smelting Works (p. 403), the last at the
Tasmania Gold Mining Co. in Beaconsfield, Tasmania (p. 419). An article can
also be found in the July 21, 1900 issue of the Engineering & Mining Journal.
All of these relate to the Edwards furnace, not a process as such.
Digging in the sources for the above references may be beneficial if more is
needed. Charleton has description of many plants, so if the name of the
particular plant of interest is known, it might still be a good source.
Does anyone know if the gentleman doing the search, Graeme Cartledge, was
putting together an article or paper on all this? His email address as it
appeared on th eoriginal posting and as it still appears in the "list of
mining historians" is no longer valid. Nor could I find him in the list for
Australian mining history.
Larry M. Southwick (Cincinnati, Ohio)
