SoUVENIR-CHARTERS TOWERS, 1872 TO JULY, 1950

Page 7

METHOD OF TREATMENT


MOST of the ore produced was treated at the local crushing mills. These were of the stamper type battery. The ore being fed from the hoppers through
.a stone cracker and then conveyed to another hopper from which it was fed into the stamper boxes. These boxes contain water and the stamper crushes the stone into pulp, which is forced through a very fine wire woven screen. The first gold recovered comes from these boxes which are charged with mercury to catch the free or coarse gold. The pulp is then washed over copper plates which are charged with mer­cury (or quicksilver) attracts the gold and these plates are scrubbed and the mercury squeezed into amal­gam balls which are later retorted. The mercury going off in a vapoulr from the lretort pot once it meets the cool air, is recovered in its original form. After the pulp leaves the gold tables (that is the copper plates) it is run through launders and then goes over wvhat is called a "Wilfley Table." This table has a perpetual shaking movement and the "Mineral Content" of the pulp, which is called concentrates and is much heavier than the residues or sands is shaken to the extreme edge of the body of pulp passing over the Wilfley table and is guided into a special vat. These concentrates usually contain a high per.r centage of the gold output of the stone and as a rule are sent to the smelters for treatment.

The residues or sands after passing over the Wilfley table are either dumped or lifted, by some means and carried away into large vats or settling pits.
(This method was used in the earlier days and is still used in some mills to­day although modern methods of cyani­dation would obviate some of the hand­ling necessary under this method of treatment.) From these settling pits the sands are carted out on to a flat, where they are spread and dried, and rolled. The sands are then carted back and placed in large vats (cyanide vats)


where a cyanide solution is poured into the vats and percolates through the sands and this solution is then drained by means of an outlet valve through pipes, where it then flows through a series of boxes, charged with zinc shav­ing~.	These	shavings	attract	the
gold content from the solution, and eventually the sha vings are roasted and then smelted when a gold bul­lion is recovered. This bullion is again smelted and by the use of cer­tain fluxes, all impurities are taken off leaving the gold bar. For the benefit of those who have not witnessed the pour­ing of the molten gold from the smelting pot into the cast iron moulds, I would say there is no better sight. An orange flame pours forth into the mould, the gold being the heavier substance goes to the bottom and the fluxes and impuri­ties form a crust on the top. This is re­ferred to as the slag.

PYRITES WORKS

THE results Welre very satisfactory
and although the directors were a very economical body of men, the credit for the success really belonged to their Manager, Mr. Brown.
The process used included calcinating and chlorinating the percentage of gold
extracted being as high as 97 per cent. in some cases.
At the time at least a dozen or more mines on the Towers field sent their tailings to the works, but there were a few men who would do anything but patronise a local institution and would send their tailings overseas for treat­ment, and in many cases after paying freight and treatment charges, the value of the gold won would show a loss to the owners, who did not patronise their local works.
The cyanide process was eventually responsible for the closing of the Pyrites Works, although the Australian Gold re­covery works (cyanide agents for McArthur	Forrest	the discoverers	of
cyanide process) was operating for a