IMPROVEMENTS IN GOLD EXTRACTION.

Westport Times, Volume III, Issue 492, 17 April 1869, Page 3

IMPROVEMENTS IN GOLD EXTRACTION.

At the present time an experiment is being tried at the Hustler's Beef Company's works, Bendigo, having for the object the separating of the pyrites from the tailings. The machine employed for this purpose is called after its proprietors, "Brown and Htansfield's concentrator," and in California it is said to be extensively used. Messrs Brown and Stansfield are Californians, who have recently come upon Bendigo with the view of introducing these machines, and also of establishing an amalgamator in connection with them for separating the gold from the pyrites by chemicals instead of the mode at present in vogue; the advantage of their plan being, they allege, that the separation can be effected at a cost of Us per ton, while the amount lot gold obtained is within five per > cent, of that indicated by fire assays. j ine machine is simple in construction I and action—a great advantage, and is : Wholly of iron. Every alluvial miner ; understands that in washing off a tini M full of stuff, the gold and heavier [particles sink to the bottom of the [ d™, while the lighter sand, &c., is gashed off, and to assist the gold in ■ sinking one action is to hold the dish | level, and give it a number of short, hoick shakes of three inches in a circular direction, having the centre of I the bottom of the dish as a pivot, jouch is the action of the machine, and exempiy; ca tj on of the principle upon wmch the pyrites, free gold, and qmcksilver are separated from the quartz-tailings. A fair idea of its B hape may be formed by imagining ■6 iron dish or pan, six feet in diamf*piir resting on an iron foundation W pivot on which it moves, the outer Pj of the pan being perpendicular ¥& six inches high; while three niches nearer the centre of the pan is

i anether similar rim, having perfor- • ations three inches long by a • quarter of an inch in breadth i and six inches apart along the . bottom of the run throughout its circumference—these perforations leading to the space between two rims. Erom the bottom of the outside rim to the centre of the pan, the bottom of the pan has a rise of two and a half inches. Over the pan is fixed a circular iron shield, having a fall from the centre to the edge of three inches, and the edge is a short distance within the inner rim of the pan. On the top of the shield is an iron cup. The tailings from the tables are conveyed by a shoot into the cup, thence they are equally distributed over the shield and fall into the pan. The motion of the pan causes the pyrites, free gold, and quicksilver to sink to the bottom, and to work their way through the perforations in the rim to the space between the two rims, while the quartz particles being light are floated away towards the centre of the pan, where they escape through an opening and are conveyed by a shoot to the tailings' heap, and are got rid of as waste, until a genius arises who can economise them in some way. In the outside rim an escape, with a regulator, is made forjthe pyrites, and immediately under the escape is a small receptacle into which the quicksilver finds its way, and which can be drawn off at pleasure by renewing a screw plug. The pyrites fall from the escape into a tub or other receiver, and are then carried off to be dealt with in order to separate the gold from them. There ean be no doubt but the machine does its work most effectually and speedily, for five tons of tailings can be passed through every twenty-four hours. Half a horse power is sufficient to drive two machines, and they are driven by a belt passed over the cam-shaft of the crushing machine and the crank of the concentrator, and the motion given to the concentrators is in its popular phrase 190 shakes in a minute. Eromthe appearance of the concentrator it cannot be an expensive piece of machinery, and judging from its action the wear and tear must be trifling, and as it takes up little room, is self-acting, and requires no extra hands to attend it, there appears no reason whatever why it should not come into immediate use at all mines where pyrites are abundant in the quartz, and worth looking after for the sake of the gold they contain.