GOLD SAVING

Thames Star, Volume XVII, Issue 5170, 12 August 1885, Page 2

GOLD SAVING

As considerable interest has, been evinced during the past month or two in the works now in progress at the New Prince Imperial battery in connection with the gold-saving process being introduced into this district by Mr H. Tapp, we give below an interesting extract from the report of Mr H. A. Gordon, Inspecting Engineer in the Mines Department, who lately made a tour of inspection of the principal gold mining centres in Victoria and Now South Wales (after having made a most exhaustive investigation of the fields of this colony) on behalf of the New Zealand Government. He says :— "I have not seen any appliance for amalgamation at work on a large scale which may be said to be complete. The great object in amalgamation is to mix the mercury with the ground or crushed material as much as possible, and to prevent it from becoming floured, or, at least, to be able to collect the floured mercury again before it leaves the amalgamator to run away with the tailings. The best principle of an amalgamator that I saw was that of ' Barker's Patent ElectroAmalgamator,'which was discovered, or, rather, perfected, by Mr Richard Barker, F.G.S., of London, in the beginning of 1883, and is now frying introduced into the Australian Colonies. This amalgamator has been tested by a number of scientific gentlemen and mining managers,. • who all agree that it is one of the best processes yet found out for preventing the mercury getting sickened by coming in contact with the base metals, and likewise from getting in a floured condition. . . . The London Times of Bth February, j 1883, likewise states that trials were made with this appliance at the company's works, near London Bridge, in the presence of a number of gentlemen interested in gold-mining, who assembled to witness a demonstration of the invention, and were highly satisfied with the results obtained. The Engineer of the 9th Feb. ruary, 1883, in an article describing this process, states:—' We have seen quartz heavily charged with sulphur and arsenic, from sulphur pyrites. One shovelful of this stuff sufficed to sicken all the mercury in the rifle, and the mercury was brought back to condition in less than a minute after the current was turned on. With the current flowing, the mercury should not be made sick. One experiment which we witnessed showed in a startling way the effect produced by the passage of the current. Four or five pounds of clean mercury being put into a china bowl, some oil was added, and the whole beaten up with a stick to a species of ointment— a process which occupied five or six minutes. A. sovereign dropped into this mixture of oil and mercury came out untouched by the mercury. For all pur* poses of amalgamation the mercury was useless, and must remain so until re- ' torted. The bowl was now nearly filled with water, and the end of a negative wire from a battery was plunged into the mercury and oil, while the positive wire was just dropped into the water, which stood 2in. or 3in. deep. The moment the contact was made with the water the oil began to rise in streams from the mercury, which could be seen collecting itself into little drops, two or three of which would Coalesce. In about three minutes the whole of the oil had come to the surface of the water, and the mercury lay, pure and bright, at the bottom ot the bowl.' I witnessed a trial made with this appli* ance by the agent for the company at Melbourne, which surprised me at the effect produced on quicksilver by a current of electricity; and I am convinced that this appliance will be the means of more gold being saved than hitherto. It consists of a common riffle-table, such as would ordinarily be placed next a battery of five head of stamps, the length and width being about the same as the tables now in use. The table has riffles, and is covered with electro plated copper plates such as those now used on the ordinary riffla-tables. Across each riffle is a bar or band of carbon, which comes down to within a quarter of an inch or so of the surface of the quicksilver in the riffle. There are like* wise sliding carbon bars which, by a mechanical motion, are made to more up and down directly above the surface of the copper plates '.that are between each riffle, so as to touch the water that flows over the tables, but not. to touch the surface of the plates. The negative wires from the battery are placed in the quicksilver and to the copper plate, wdile the wires from the positive pole are attached to the carbon bar or bands that are placed across the box, thus sending the current through the water into the quicksilver. I mixed up some mercury with grease in a dish to test the effect that the electricity had upon it, and, although the mercury was so sickened with the grease that it was perfectly useless for amalgamation, in a few minutes after the current was turned on, the effect produced was almost magical: the grease and impurities came boiling out of the mercury, and left it in a pare and bright condition. Mr J. Naylor, of Stawell*,' informed me that a company with which he was connected had made arrangements to erect a plant of these amalgamators to treat the heaps of quartz-tailings then on the ground, and he promised to send me v a full description, with the result of its manipulations/