The Merrill-Crowe process for gold and silver recovery yields a low grade concentrate containing high levels of zinc and copper._x000D_
External refining charges and high transport costs prompted the company to establish its own enrichment facility._x000D_
The route chosen was a wet chemical treatment which converts the gold, silver and other metals to their chloride. This is achieved with hydrochloric acid and sodium hypochlorite. Gold is recovered from the resulting filtrate by cementation with copper._x000D_
The solid residue from the gold process is washed and treated with ammonia which dissolves the silver chloride. Metallic silver is recovered from this solution, again by cementation with copper.