GOLD-SAVING PLANT.

Mount Ida Chronicle, Volume XXI, Issue 1106, 12 February 1891, Page 3

GOLD-SAVING PLANT.

The largest and most modern gold-saving- plant now in the colony is one latety erected in an out-of-the-way corner of the Ohinemuri (Upper Thames) goldfields, known as the Waihi, within a few miles of Taurangi. As, however, it is owned by an English company, very little has been known about it in the colonial papers. An interesting description of the works has been sent by a recent visitor to a Wellington resident, to whom we are indebted for the particulars here given. The company is working upon a mammoth reef 75ft. in width, composed of low but regular grade quartz, but .payable when economically treated. The ore is trucked from the mine to kilns, and there burned with wood fuel. On cooling down, the calcined material is trucked away to the battery, and put through the from which it falls into hoppers, and is fed into the stamper boxes kyiin ingenious antomatic gear, one man being able to attend to as many as *2O head of stampers. In the crushing process, the stuff must be reduced .to ao almost impalpable dust, for it is made to pass through gratings with 3(500 perforations to the square inch, and gratings of the extraordinary fineness of 64iM) to the inch have at times been used. On being brought to this condition the stuff is caught up by a spiral contrivance on the endless screw principle, and elevated to another large hopper. Thence it is conveyed to amalgamating pans, where at is brought into contact with quicksilver and chemicals, and steam is also turned on. Each separate " charge " of the pans is allowed to remain in a boiling-hot state for four or five hours, and is then run off into a "settler," the amalgam of gold and quicksilver being first removed by means of siphons into sp°cially-made bags. After being squeezed aud retorted (to extract the superfluous mercury), the bullion is smelted into ingots of about lOOOozs., sealed up in boxes, and shipped away to London. All the plant is driven by water-power, liy means of three Pelton wheels—one of which, it will be remembered, was on view at the Wellington Exhibition—but powerful steam engines are also being erected to provide against summer droughts. Experts estimate thatthe works will shortly turn out bullion to the value of £10(),0(»0 a year, for the "yield does not depend so much upon the discovery of sensatioual runs of gold as upon the careful and systematic treatment of a large lode. Shares in the company were purchasable a few months ago at about 4s , but could not now be obtained for live times that sum. An Auckland contemporary recently stated that the company makes a clear profit of 255. from every ton cf ore treated—" Post."