"The United Pyrites Company's Works are situated about three quarters of a mile from Spargo Brothers, and are on the northern side of the Marong road, in Pinch-gut Gully. Two processes are followed at these works, viz., the amalgamating process and the treatment by means of chlorine gas. The latter is called the Newbery-Vautin system, and the mode pursued is that laid down by Mr. Cosmo Newbery and Mr Vautin, whose names have been given to the process. Mr. Edwards manages these works. Three reverbatory furnaces are used to roast the pyrites, which is weighed in the truck before being put into the furnaces. At this weighbridge a sample of each lot is kept, and if the yield is not equal to expectation, the works are carefully gone over to see where the fault occurs. Care is taken at the furnace to regulate the heat, otherwise the pyrites might slag instead of roasting evenly right through. An immense revolving furnace (made of boiler iron) was used at these works. It was found to be suitable for treating blanket sand, but was not a success for roasting coarse pyrites. The process of amalgamating by means of Chilian mills is the same in these works as at the Western Works, but the United Works are on a larger scale, and eleven mills are utilised. It is the chlorine gas process which is most interesting here. The gas is made from sulphuric acid, black oxide of manganese, and common salt, and the gas is introduced into huge vats, where it works its way through a filter of pieces of quartz and then through the bed of roasted pyrites lying above. The action of the gas transforms the gold into chloride of gold. This is easily dissolved in water, and in that form is drawn off into huge delf jars, where the use of sulphate of iron precipitates the gold to the bottom. A small battery—eight head of stamps in two boxes—is in use here to crush small consignments of stone sent for trial. Test crushings come from all the Australasian colonies, and even from India. The jars used are manufactured at Epsom, and some of the salt used is also of home manufacture, from the Salt Lakes on the Northern plains. Mr. Edwards took us over a new building in course of erection, and in which the chlorine gas is to be generated in the midst of the pyrites— a still further advancement in the new process. There is some very good machinery in this new building, and the tailings from the ordinary pyrites works will also be treated by this chlorine gas system, which has been found to work well at Mount Morgan, in Queensland. The purest of gold is obtained by this process, the gold passing in solution into a charcoal filter, from which it emerges in the shape of metallic gold. We saw some nice cakes of retorted gold at the works. One of 26oz. was from some New Zealand pyrites (2½ tons), and assayed over 23 carats. There were also cakes of Avoca gold, of silver, and of the tremulous amalgam." (The Argus, 4 February 1887)Two handwritten letters to the Ballarat School of Mines on Bendigo United Pyrites Company Letterhead.bendigo united pyrites company, pyrites, ballarat school of mines, j.j. deeble, joel deeble, joel james deeble, a.m. dean, fred j. martell, martell, s.h. cowan, letterhead