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The low-grade copper ore in a high-latitude cold region consists of primary copper sulfide ore, secondary copper sulfide ore, and copper oxide ore. The ore properties gradually change with the depth of the ore body. Under natural temperature, medium temperature, or acidic conditions, tennantite and tetrahedrite in the primary copper sulfide ore, secondary copper sulfide ore, and combined copper oxide ore are easily leached. For shallow low-grade copper ore, sulfuric acid column leaching in atmospheric temperature was conducted at temperatures of 13 °C 23 °C for 34 d, followed by medium-temperature bio-oxidation column leaching with leaching bacteria added at temperatures of -23 °C-30 °C, achieving a copper leaching rate of 65.01%. For medium-deep low-grade copper ore, a pilot test was conducted under conditions of ore particle size 50 mm and a column leaching time of 288 d, achieving a copper leaching rate of 41.66%. [ABSTRACT FROM AUTHOR]

Abstract: This paper discusses a case study on a bioheapleaching system operated commercially at Zijinshan copper plant in China, which applied bioheapleaching–SX (solvent extraction)–EW (electrowinning) to treat a distinct secondary copper sulfide ores. The operating parameters and microbial community structure succession were summarized in this paper, and their correlation with the system characters is studied. Over the four years of industrial operation, fully taking advantages of high acidity, high iron concentration, high salinity and elevated temperature caused by the high content of pyrite (5.8%) within the ore, the growth of iron oxidizers was inhibited and that of sulfur oxidizers were promoted to dominate the heap. Copper was leached efficiently with a recovery of 80%, according to the residue analysis and iron was balanced at low cost by jarosite formation in the heap, using appropriate engineering technologies such as multi-lift permanent stacking in coarse particle size (P80 =40mm), without agglomeration and aeration. The total operation cost was low at 1.10USD/lb at a low copper grade of 0.38%. The case study presented in this paper provides operational data and analysis that would benefit the optimization of similar bioleach plants of secondary copper sulfide. [Copyright &y& Elsevier]

Abstract: Bioleaching, also referred to as minerals biooxidation, and bioremediation have been widely employed commercially for heap and dump bioleaching of secondary copper sulfide ores, sulfidic-refractory gold concentrates and treatment of acid rock drainage. Technical and commercial challenges, identified in this paper, remain for bioleaching of primary sulfides and complex ores. New frontiers for the technology exist in processing massive sulfides, silicate-locked minerals and in the more distant future in-situ leaching. Decommissioning of cyanide heap leach operations and stabilizing mine wastes using biotechnology are opportunities requiring intensive and focused research, development and engineering efforts. [ABSTRACT FROM AUTHOR]