QUARTZ CRUSHING.

New Zealand Times, Volume XLI, Issue 6956, 7 September 1883, Page 6

QUARTZ CRUSHING.

What promises to be a most important discovery in the treatment of mineral ores has been made in Auckland, and is thin described by the New Zealand Herald : When Mr Hunt imported the necessary machinery tor the brick and tile works at Avondale, he got a machine which is known at Home as a disintegrator. The machine consists of two wheels revolving within each other, one, of course, being s ightl/ smaller than the other. On the periphery of the loner and smaller wheel are a series of strong steel bars across the face of it. On the under side of the outer wheel are a series of steel bars, also across the breadth of the rim of the wheel. These two wheels run at about a thousand revolutions per minute in opposite directions, and when any atone or other hard substance gets between these when in motion, it is at once reduced to a powder. This disintegrator was imported by Mr Hunt, under the belief that the Auckland clays contained stones, as is frequently the ease in Britain. It occurred to Mr George Fraser, of Phoenix Foundry, to try this disintegrator for the reduction of quartz. A quantity of as hard and flinty quartz as passible was obtained from the Golden Crown at the Thames, and on Saturday last Mr Hunt got up steam, and the stone and the machine became acquainted with each other. The stone was reduced to an impalpable powder, like the finest silk-dressed flour, aud this was done at the rate of ten tons an hour. A new future for quartz mining is thus opened up, aud if this method of reducing the stone be employed in connection with McKay's pans, of which Mr Brown has some at work at tho Thames, it is anticipated that not only a vast quantity of stone can be dealt with in a very short time, but by the emp’oyment of a sufficient number of pans, all the work connected with quartz crushing aud gold saving could keep pace with each other. It is estimated that a fall plant to carry out this method will consist of the following machines : —Steam or water power equal to 30-horse power, which will provide the force to set them all in motion. One ordinary stons-breaker will break the quartz to a size which will enable the di-in-tegrator to deal with it. Two disintegrators will be employed, one set so fine as to reduce the atone to the finest possible state of division. From this machine it will be raised by an elevator and stored in bunkers, to be fed to the two McKay pans as required. In these pans the stone flour will be subjected to further reducing nction, and when it passes from these to the “ settler " it h calculated to be in the condition of fine ooze when mixed with water. In the “settler,” water will be added slowly but steadily, and the slow agitation maintained within keeps the powdered stuns in a state of suspension in the water, while the gold sinks to the bottom and is united with mercury. As the water steadily flows in, there is a steady ovei flow from tho “ settler,” and this overflow carries with it all earthy impurities, and at the end of about an hour and a-half or two hours, the silt is all removed, the water quite pure, and the gold, however fine, at the bottom. The turn 'of a tap or two disposes of the amalgam through apertures provided for the purpose, and the “ settler ” is again ready for another charge. Thus the process of reduction and amalgamation go on simultaneously. All tables, blankets, ripples, &0., are dispensed with, and the whole of the amalgamation takes place within the “settler.” It is estimated that such a plant could reduce to the finest powder 100 tons of hard quartz in ten hours, and by employing two sets of McKay’s pans, that is four pans and two “settlers," the work of amalgamation would keep pace with , the crushing. Tho cost of such a plant is estimated at about £SOOO, and from what has been done with these pans already, it is believed that at least two ounces ef gold would be saved for one that is now secured by the process employed at present.