NEW GOLD-SAVING APPARATUS.

Inangahua Times, Volume VIII, Issue 1276, 25 May 1883, Page 2

NEW GOLD-SAVING APPARATUS.

An improved method for saving very fine or " float " gold from tailings has just been perfected by Messrs Birchall and Twining. These gentlemen have been at work upon the invention for some time past, and from experiments made with half-sized models which have been constructed, the results are likely to .prove entirely satisfactory.

The usual method of extracting gold from quartz-crushing machines is by passing the tailings over copper plates coaled with quicksilver, which is supposed to catch all the gold which such material may contain, the metal as it sinks becoming amalgamated with the quicksilver. Very fine or "float" gold is known, however, to frequently pass over these tables and escape, quartzcrushing machines in some cases losing a considerable quantity. Messrs Birchall and Twining's invention is designed to catch such gold as escapes under the present method. According to their plan the tailings are passed upwards through perforated plates, on which rests a body of mercury, the fall or " head " being about eight inches for each plate. The gold passing through this bath of mercury is retained and amalgamated, it being almost impossible for the finest grains to escape. The number of times which it is advisable to pass the tailings through such a plate depends, of course, upon the quality of the matemi and fineness of the Igold. After rising through one perfo<ated plate, the tailings continue their fell, rise again through the next one, and so on. The experience of the inventors in the experiments, which have been made with tailings of very heavy material and very fine gold, is that about 90 per cent, is saved after the material has been passed through two plates. The method has been devised especially for beach workings, and it will also pass ironsand through without any difficulty- It will doubtless prove of great value in quartz-crushing where gold is at present lost, The apparatus — if the contrivance can well be so called — measures only about 4ffc x 3ft x 2ft Gin. A company may not improbably be formed to introduce it throughout tlio Colony.