The technology of heap leaching is widely developed in Chile, with more than 85,000 t of ore processed per day. With the improvement of the industrial application, the thermophilic bacteria are considered to be indispensable for the dissolution and high copper leaching rate of refractory metal sulfide minerals in biohydrometallurgy. The extremely thermophilic archaea, due to find more their tolerance to extreme conditions, are eventually identified in the laboratory

and applied gradually into the biohydrometallurgy, especially for the bioleaching of a highly refractory metal sulfide ores [20]. The efficiency of the process of bioleaching and biooxidation is controlled by the characteristics of the metal sulfides [151]. Heaps and stirred tanks, which are two different engineering applications from traditional metallurgical industries, are mostly applied and implemented into the bioleaching and biooxidation of metal sulfides

minerals in terms of biohydrometallurgy. Biohydrometallurgy is now applied on a commercial scale for the leaching of copper and the pretreatment of refractory gold ores and concentrates. BioCOP™ process is famous for the demonstration buy GSK2118436 plant at Chuquicamata, in northern Chile. It produces 20,000 t of cathode copper per year by the process of the stirred-tank bioleaching and biooxidation of copper sulfides and BacTech/Mintek process. Similarly, there is also an agitated tank process used to deal with the Decitabine in vivo copper sulfides, built and further developed by Bac-Tech Environment. The GEOCOAT and GEOLEACH™ processes, which both incorporate Hot Heap™ control technology, are widely used for the biooxidation or bioleaching of metal sulfide minerals through the craft of the leaching heap. The process of GEOCOAT is applicable to the biooxidation of refractory gold sulfide concentrates and to the bioleaching of copper, nickel, cobalt, zinc, and polymetallic base metal concentrates. The GEOLEACH™ technology is designed to maximize heat conservation by the control of aeration and irrigation rates, which

is suitable for the whole ore systems. The general process of the heap leaching includes: the stack of metal sulfide ores on a lined pad; irrigation with the combination of a dilute sulfuric acid culture and the leaching bacteria; the control and monitor of the bioleaching conditions and environments; collection and transportation of pregnant leach solution (PLS); the processes of conventional and traditional metal extraction and electrowinning. The mineral ores that are used for stack or heap usually are pre-treated by crushing or grinding into the specific sizes. Considering the aeration of the leaching heap and the limitation of natural convection, the gangues are used for the acid agglomeration (the GEOCOAT process) and sometimes the lines are deployed on the pad under the stack to supply the oxygen (O2) and carbon dioxide (CO2).