The first 16 hours of leaching is p

The first 16 hours of leaching is principally the dissolution of the gold grains with NaCN at 0.07 % strength and maintained by regular dosing of cyanide under an alkaline condition. On the 16th hour, activated carbon is added to the pulp, while, no more addition of lime and NaCN is carried out up to the end or 24th hour. The 16 hours adsorption is carried out under “run-out” condition of reagents. This is to prevent the repeated dissolution of the gold already adsorbed by the activated carbon. In the adsorption stage, leaching of the residual gold still in the ore is occuring, but at a reduced rate and efficiency. In both the leaching and adsorption stages, air is injected to the cyanidation tanks at a rate to produce at least 5% dissolved oxygen (O2) to the pulp. In theory, maximum dissolution of the gold occurs at a 6 : 1 concentration ratio of [CN-] to[ O2]. At the end of adsorption, the loaded activated carbon is harvested with the use of 20mesh aperture screen sieves and washed, while, the tailings is pumped to a bucketwheel to separate the solid waste from the barren solution. A complete leaching cycle takes about two days to complete, from loading and unloading in the leach tank or a total of 8 cycles per month. This is equivalent to an overall Plant treatment capacity of 240 tons per month.