TWhile leaching is occurring, senso

TWhile leaching is occurring, sensors are used to monitor the pH and dissolved oxygen levels. If anoxygen plant is available, oxygen gas is added at an injection port on the SLR to maintain high levels of dissolved oxygen. If not, hydrogen peroxide can be added by a dosing pump controlled by the SLR PLC or Sepro Leach, a chemical oxidant, can be added by a feeder, also controlled by the SLR PLC. A pH monitor is used for safety to ensure no cyanide gas is produced. After the leach cycle, the pregnant solution is drained using Sepro’s unique drainage system. This system allows the solution to drain quickly even in the presence of very fine material. As the pregnant solution is drained through the concentrate bed, it is naturally filtered producing a clarified liquor. This improves electrowinning efficiency. Water is added and drained to wash gold bearing cyanide solution from the ore that remains in the tank. A second and third wash can be completed to reduce the cyanide levels in the ore discharged in the tails. Once the wash water is drained, the water is added again and the slurry is agitated to allow pumping. The material is removed through a tank bottom valve and pumped by peristaltic pump to the desired location in the plant.