Solution Management
Once sufficient ore has been stacked on the pad, the solution distribution piping is extended to the newly-stacked area. Biooxidation initiates rapidly as the new area is populated with active, adapted microbes introduced with the solution. Solution is applied at variable rates by conventional irrigation equipment, and percolates through the heap to the drain layer where it is collected in perforated piping. The drainage pipes conduct the solution to a collection ditch running along one of the long sides of the heap. The ditch discharges into the appropriate pond based on grade and pH. Solution is pumped from the ILS pond back to the distribution piping and sprinklers on the active areas of the heap. The PLS solution reports to downstream metal recovery.
During periods of heavy rainfall, it may be necessary to reduce or eliminate the addition of fresh make-up water to the system and to maintain the PLS grade by reducing the solution bleed rate. A detailed water balance, taking into account the site climatic conditions, must be performed for each GEOLEACH™ project and the results used to size operating ponds and emergency storage ponds.
