A minimum Sample Weight Required for Liberation Analysis of Copper - Bearing Minerals at the Sarcheshmeh Copper Mine

Measurement of liberation degree is of prime importance in determination of grinding and separation circuits performance. Subsampling and particles mounting, which are the main stages in the preparation of polished sections, could affect liberation degrees obtained by the mineral counting method. At the Sarcheshmeh copper mine, particles mounting is carried out at high pressure (4000 psi) and high temperature (300F). In this paper, the method of percent weight determination of copper - bearing minerals (chalcopyrite, chalcocite and covellite) and the error on liberation degree estimation are discussed. In order to determine the appropriate weight ratio of sample to mounting powder, 10 samples with five different weight ratios were examined. It was found that the weight ratio of 4g sample to 11g mounting powder had the lowest error. For each mineral, the minimum number of particles, which must be examined to reach an acceptable accuracy were determined.