PRE-TREATMENT OF FEED TO NON-STIRRED SURFACE BIOREACTOR

A method for pre-treating feed supplied to a bio-reactor is provided to reduce leachate time and control microbial population effectively when gold and a non-metallic concentrate are extracted by using a non-stirred surface heap leach bio-reactor. A method for pre-treating feed supplied to a non-stirred surface heap leach bio-reactor comprises a step of applying a first and a second pre-treating solutions to the feed to the non-stirred surface heap leach bio-reactor to the feed in sequence, wherein the first solution has more than 5g/l of Fe and pH of less than 2 and the second solution includes substantially higher microbial population, which is selectively controlled regarding a heap PLS solution. A method for controlling microbial population used in the non-stirred surface heap leach bio-reactor comprises a step of passing a solution including microorganisms through an inoculant generator where a concentrate is supplied to select the microorganisms which are controlled in optimum levels regarding a specific toxic compound contained in the concentrate.