Optimization of crushing size for heap leaching of oxidized copper ore at the Berkarinskoe deposit: from laboratory studies to industrial implementation

This paper presents the results of studies on the optimization of crushing size for heap leaching of oxidized copper ore at the Berkarinskoe deposit (East Kazakhstan Region). The initial technological regulation for heap leaching was developed on the basis of comprehensive laboratory studies including chemical, phase-chemical, granulometric, mineralogical, X-ray diffraction, and thermogravimetric analyses, as well as laboratory percolation column tests on −10 mm material, which yielded copper extraction of 78.8% over 90 days. Following industrial implementation, pilot-scale column tests on −25 mm and −30 mm fractions showed that the −25 mm fraction achieves 70% copper extraction in 100 days with acid consumption of 99.4 kg/t ore (10.4 kg/kg Cu), versus 128 days and 114.7 kg/t ore (11.3 kg/kg Cu) for the −30 mm fraction. The two pilot columns were charged with different ore types — oxidized ore (K-1, −25 mm) and mixed ore (K-2, −30 mm) – which differ markedly in phase composition (9.4% versus 54.4% secondary copper sulfides). The study provides empirical, pilot-scale results confirming the favorable physical characteristics of the ore.