The preferred alternatives in heap design and their motivation are identified as - -normal heap leaching, to be generally applied wherever possible, - flooded vat leaching, to be applied where wetted ore lacks adequate cohesion or if limited space necessitates it, - thin layer leaching, to be applied where deleterious vat chemistry necessitates it._x000D_
A number of the following features would probably be incorporated in the optimization of normal local heap leach operations - pre-cyanidation - pre-agglomeration - retaining walls - staged (counter-current) heap treatment - control of calcium levels - reduced pH and trickler irrigation