THE RUSSELL PROCESS IN AUSTRALIA. oul! 
The crushed ore from the rockbreaker was dumped on to the 
drying floor, where it was spread, and the salt added to it. When 
dry the mixture was taken by trucks to a hopper, thence by an 
automatic feeder to the Wall rolls. These were used to crush to 
one-quarter inch size. The crushed ore fell into a revolving screen ; 
that passing through, forming 25 per cent. of the whole, was taken 
by a spiral conveyor to the fine-ore elevator; the coarse portion 
fell into a link-belt elevator, and thence went to the smooth rolls. 
These rolls were set up tight. The crushed ore fell into a second 
revolving screen. All which passed through went to the spiral 
conveyor, thence by the fine-ore elevator (thin buckets bolted to 
a rubber belt) to the roaster bins. That which did not pass 
through the screen formed only a small percentage of the whole, 
and was returned to the link-belt elevator, and so to the smooth 
rolls again. At the end of the conveyor trough, where the fine 
ore fell into the elevator, a small pipe sampler was fixed, which 
furnished a continuous stream of pulp. From the sample so 
obtained the results given later on were calculated. The screens 
were covered by brass-wire cloth containing 480 holes to the 
square inch. The Westinghouse engine furnished the power for 
the whole of this portion of the plant, and gave satisfaction. 
Owing to scarcity of ore, no effort was made to find the full 
capacity of the plant; but 15 tons per shift of eight hours were 
crushed with ease. Apparently the capacity of the two sets of 
rolls was much greater. The first screen had a screening surface 
of about 25 square feet, the second about twice as much. With 
perfectly dry ore, and so long as the rolls were doing good work, 
these screens gave no trouble; but it was evident that the second 
one would have been better if larger. The secret of successful 
crushing appears to be the perfect drying of the ore; in fact, the 
ore crushes and screens better if it is quite hot. The salt was 
added at the drying floor, and was simply spread over the top of 
the ore in measured quantities, and became mixed in passing 
onwards through the mill. At first, owing to Customs regu- 
lations, rock salt was used, which had, of course, to be passed 
through the rockbreaker. Subsequently, ordinary coarse salt was 
used. 
The mixed pulp was fed from the hoppers into the Howell 
roaster by a small spiral conveyor, driven from a pulley on the 
driving shaft of the roaster. The quantity was regulated by a 
sliding door on the hopper. The roaster was fired by wood at one 
end only. An auxiliary fireplace was tried, but proved unneces- 
sary, and the waste heat from the roaster was also found sufficient 
for the drying floor. The roaster was tried at many different 
speeds, but we found one revolution in one and a half minute 
gave the best results, and that the capacity of the furnace did not 
exceed 15 tons in twenty-four hours. 
