The holding tank is used to accumulate the concentrate during each cycle. The material is dewatered by allowing the solids to settle and decanting the excess water just prior to each rinse of the gravity concentrator. The timing of the valve opening is such that the fine gold particles are allowed to completely settle before the water is decanted. The tank is equipped with load cells to measure and record the amount of material treated per batch. When the desired amount of material is stored, a peristaltic pump is used to transfer the material to the agitated leach tank. Using an ultrasonic level sensor, the appropriate amount of leach solution is added to the tank and the agitator is started.