The Alderley innovation Turning brown to gray
(sulphides to oxide ore)
The Alderley 'technology' is intended to serve as a replacement for the POX system. The autoclave - Metates Old - roasts and oxidizes the refractory sulphide ore and releases the gold. The oxidation is now to be achieved by a secret recipe and flowsheets - Metates New - in combination with heap leaching - Oxidation Heap Leach. Brown becomes gray. Then it goes to a classic mill with a simple flotation and further cyanide process. The supply of oxidized ore facilitates essential work of the mill feed and the final gold extraction. The significant reduction in CAPEX, CASH COST and a much more environmentally friendly production (90% Co2 and water reduction) would go hand in hand with success. The exact parameters - oxidation cycles; Duration vs recovery - will be analyzed over the next 12-18m. The cyanidation of simple oxide ore takes about 2-3 months. All in all, this could be the beginning of a new paradigm for the processing of low grade refractory gold ore analogous to copper mining.
Geology and mineralization
Metates is refractory sulfide ore. The gold-silver mineralization occurs as sulfide veins and disseminates in both intrusive and sedimentary host rocks. Ultra-fine-grain refractory gold ore which can hardly be recovered through classic cyanidation. The fire resistance is mainly based on the encapsulation of extremely fine gold particles by sulfide minerals, which are not affected by the cyanide leach solution.
One of the main advantages of the deposit is that the ore body rises vertically to over 300 m; only 1.1 stripp off. Highest grade close to the surface which enables higher cash flows in the first few years and a shorter payback period. This approach is now being followed in Stage1.
Peter