The pore size distribution of activated carbon can be classified into three groups. The groups are based on the size range of porediameters found in activated carbon: the micropores are less than 2 nm in size, the transition pores or mesopores range in size from 2 nm to 50 nm and the macropores are greater than 50 nm (Dubinin, 1966). The porosity of activated carbon is a very important property since it greatly influences the adsorption of aurocyanide. The macropores provide passage to the micropores and access to the interior of the carbon matrix. The micropores created during the activation process are responsible for the very large surface area used for Au adsorption. Typically, activated carbons have BET surface areas in the range from 500 to 1400 m2/g and the relative (%) contribution of each pore structure to the total surface area and adsorption process vary in the order: macropores (_0%) < mesopores (5%)_micropores (95%) (Lartey et al., 1999).