THE RUSSELL PROCESS IN*® AUSTRALIA. 309 
having been obtained, and that the failure was due to defective 
mechanical arrangements and to lack of ore. No detailed results 
were ever made public. 
The ore at the Webb’s Mine consisted principally of argentiferous 
fahlerz in a gangue of quartz-veined slate ; the fahlerz contains a 
good deal of copper and antimony. 
An extensive lixiviation plant was erected at the Broken Hill 
Proprietary mine some years ago, and is still working. The writer 
has failed to obtain any information about the working of this 
plant beyond a statement from the secretary of the company to the 
effect that the Russell process was tried and found to be of no 
value to them. The nature of the material treated (tailings from 
the concentration of lead carbonate ores), and its extremely low 
grade (the accounts for over five years show an average of only 
8k oz. per ton), render this very probable. 
In 1891 the writer did some experimental work with the process 
on the silver ores of Rivertree, which led later on to the erection 
of a plant to treat the ores on that field. The results of the experl- 
ments were published in a pamphlet printed at Brisbane in August 
of that year. The mill subsequently erected underwent many 
vicissitudes, and is now partly dismantled, the ore supply having 
failed utterly to come up to expectations as regards quantity. 
During 1895 experiments on a large scale with the Russell 
process were made at the White Rock Mine, at Drake, New South 
Wales, which were successful, and a large lixiviation plant i is now 
being erected at that mine. It is with the results obtained at the 
mill erected at Rivertree that this paper will deal. Although 
siliceous ores of silver have not yet been found in large quantities 
in Australia, the possibility of finding such ores remains, and our 
conditions are such that it is probable the discovery will be made 
in country where a cheap method of reduction on the spot will be 
needed. The writer hopes, therefore, that a record of the work at 
Rivertree may yet be of value to some Australian metallurgist. 
The silver lodes of Rivertree, New South Wales, occur in a 
granite formation, which is overlain by beds of altered shales of 
Devonian age, and is penetrated by dykes of diorite and quartz- 
porphyry. 
The mineral-bearing belt is about 3 miles long and 2 miles wide, 
and contains numerous veins of quartz which carry silver. The 
veins are very small, few averaging 6 inches in thickness for many 
feet, and the ore shoots are not continuous in either length or 
depth. The ore, when clean and free from gangue, is generally 
quite rich, and consists of quartz-carrying galena, fahlerz, blende, 
pyrite, and arseno-pyrite, with proustite in microscopic crystals. 
The veins are oxidised to very shallow depths and only so far as 
the granite is decomposed. When the unaltered granite is reached, 
the veins become smaller and poorer and no longer pay. In a 
