Air Requirements
Air supplied to the GEOLEACH™ heap serves two separate purposes:
- Provides oxygen for oxidation of the sulfide minerals
- Removes heat by evaporating water, allowing heap temperatures to be controlled within the optimum range for biooxidation.
The flow rate of air required for heap temperature control is typically an order-of-magnitude more than that required for the oxidation reactions and for the microbes during peak oxidation periods. The air supply and distribution system is therefore designed on the basis of the heap cooling requirements. The specific flow rate depends on the mineralogical and chemical composition of the ore, the quantity of sulfide per unit volume of heap, the rates of reaction of the sulfide minerals, heap geometry, and the ambient conditions at the project site.
Air is supplied by low-pressure fans equipped with variable-speed drives. The air distribution piping consists of parallel stringers, connected to large-diameter headers running the length of the pad.