COLD-SAVING PLANT.

Te Aroha News, Volume IV, Issue 202, 7 May 1887, Page 1

COLD -SAVING PLANT.

— ♦- — Aucklxm), April 29. i Pkokkssor Brown delivered a lecture at the University College la&t night on the extraction of precious ores norn Thames enmrtz. In the cour.se of )u.> lcmarks he advocated the de\oting of the greater pni t of the Thames School of Mines, and liny money which might be in itri hands, i to establish an experimental plant for experimenting on a conuneiciiil &cale. He detailed the exact nature of the \\ ork i which he thought should be earned out. In the hi\st place the ores at j the Thames weie in the main poor. This could be remedied by concentration, and so the iirst tiling to do was to find out the best means of doing this. He knew , that there >\ as a concentrator attho Thames, | but he also knew that it was not worked in a scientific manner. He also knew that many thoughttheThamesores could not beconcentrated, but this was ab&urd, because at the batteries they used blankets, which were practically concentrators. Among a number of particles in water large particles would settle before small ones, and with particles of the same si/c the heavier sank Hi st. Concentration therefore depended upon n\ o distinct things: hrbt,di{Ference of size, and s L n;ond, difference of weight, and unless tho^ewere considered it was impossible to concentrate. No matter how line the gold was, if it was all the same si/c it could be concentrated. They could get the large gitiin.s easily enough at the Thames, but tho line gold was lost. The first thing na,s to ficpaiate the particles according to their size, and then they coaid use the concentrators, &uch as the " Triumph," and get a proper concentration. All the processes were tendered easier and cheaper by concentmtion. After concentration came the consideration of the best piocess to be employed. Theie were crushing and simple amalgamation, ci usbing and amalgamation with chemicals at a high temperature, leaching after chlorination i oasting, treatment, with chlorine and leaching, and smelting. The smelting pioces.s wa.s far tho best, us it would gi\e .ill the gold in the ore. This process, however, was impossible witli the Thames oius unless they were concentrated, on account of the \eiy large proportion of silica they containod. The processes used in all parts of the woi Id were lew in number. If conccntiation was found to work then the costly furnaces which had been elected could be utilised, so that for a small expendituie in evpeiimenU they might lender the plant worth £12,000 or £14,000 useful again. By putting down £100 they had an e\ei. chance of gaining £12,000, which wore better odds than the totulisator offered. What lie pioposed to do wis to ask the (io- \ eminent for £200 which had been voted to him for tiavelling expenses, and also for a grant of l'.")00, on the understanding that I'.'iOU uould be raised in Auckland. Mr Firth mo\ ed, " That a committee consisting of Di. Purchas, Messrs Green, Keid, and Saundeis beappointed to wait on the banks, insurance companies and others with a view io raising by subscription the £.~>oo required, and that they call a meeting next \\eck and leport progress." Mr Fraser seconded the motion, which was carried.