JOHNSON'S PROBESS FOR GOLD SAVING.

Auckland Star, Volume XXX, Issue 55, 7 March 1899, Page 2

JOHNSON'S PROBESS FOR GOLD SAVING.

Under this system the ore or slime is first treated with cyanide in a mixing vat, provided with a Vortex Mixer, in which is a Centrifugal mixer vane, which causes the contents of the vat to circulate through a fixed circulating pipe, thus continually drawing the ore or slime from the bottom of the vat and delivering continually at the top to bring the gold into complete solution. The treated slime or ore is then run into a filter or leaching press; it is then washed with water to displace the cyanide solution. Both the strong liquor and the washings from the filter or leaching press are discharged into a receiving tank, from whence the liquid runs through dnc boxes to precipitate the gold. The press is then unscrewed, and the residuum of the chambers is conveyed to the waste heap; the whole cycle of operations not taking more than an hour. In the ordinary way it takes many days to extract the gold contents. It is stated that the process of natural subsidence and percolation, which have been tried on the Eand, have not resulted in more . than 55 per cent of extraction. The process of washing by water being one of displacement of the stronger solution from or-e or slime is consequently more perfect than any system of decantation, because even if the system were continued ad infinitura there still would be cyanide left, whereas in a system of working by displacement the whole of the cyanide solution is pushed out of the ore in front of the water, thus securing the maximum of concentrated solution and the minimum of water. Mr A. E. Burcher will have a testing plant here shortly, and will treat small parcels of ore or slime free of charge for those interested in the process.