lime was added to increase the pulp alkalinity to 0 5 g l available lime ahead of cyanidation the ph of the pulp was thereby raised to about 11 5 for cyanidation the ph preferably should be no lower than about 10 the cyanidation circuit consisted of four tanks with an intermediate carbon in pulp stage between no 2 and no 3 cyanidation tanks this additional cip stage provided for gold removal from the high tenor leach solution which in turn enhanced gold leaching in the downstream leach tanks the total retention time in the cyanidation circuit was 72 hours terminal cyanide concentrations were maintained at approximately 2 g nacn l the cip circuit consisted of the intermediate cip tank in the cyanidation circuit and a subsequent series of five cip tanks with one hour retention time per tank carbon was retained in each tank by screens installed at the discharge of each tank carbon transfer upstream between tanks was accomplished with centrifugal pumps loaded carbon 3 35 mm by 1 18 mm 6 by 16 mesh from the second cip tank was transferred to the intermediate cip tank once fully loaded the carbon was transferred from this tank to the 420 micrometer loaded carbon vibrating screen.