TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Bioleachate: The bioleachate solution contains a lime softener, an ion exchanger, an electron depositor, an iron cementation or reverse osmosis process. The concentration of bioleachate solution recovered during the first process is 70-90 %. The bioleachate solution collected from the second heap comprises refractory sulfide ore which is biooxidized.Preferred Conditions: The pH of the bioleachate solution is raised to at least 5 during the process, preferably 5.5-6.Preferred Method: The pH of the bioleachate solution is raised to at least 5 to form a precipitate. The formed precipitate is removed from the solution subsequently, the pH is adjusted to 1.2-2.6, preferably 2-3 to favor biooxidation. The bioleachate solution is recycled to the heap by agglomerating refractory sulfide ores with bioleachate solutions and adding the agglomerated refractory sulfide ore particles to the heap. Ferric ion is added to the processed bioleachate solution to increase the ferric ion concentration to 5-20 g/l. EXAMPLE - An agglomerated ore was sprayed with 8 kg of bacteria and taken in 3 different columns (A, B and C). A was provided with air flow and B and C were closed. A 9K salt with strength 0.2 and pH of 1.2 was passed at top of A with rate of 200 ml per day. After 3 days the solution eluting from the bottom of A was pumped to B without retreatment. After 3 days the eluant from B was pumped to C and collected until the volume was 1 l. After 15 days the eluant was treated with limestone to raise the pH to 5.5 and precipitated. The treated solution was mixed with untreated solution (pH 1.6 or less) in the ratio of 85:15 and after 18 days of the operation the treated, untreated solution was used to replace the addition of fresh pH 1.8 solution in A. The drop in rate of biooxidation was noted between 29-31st days. The rate of iron leaching dropped from 0.132 % per day to 0.103 % per day. On the 15th and 39th days the pH was 1.820 and 1.600, redox potential was 0.576 V and 0.542 V, and iron content was 6928 parts per million (ppm) and 7312 ppm, respectively. The percentage of iron leached at the 15th and 39th days was 0.40 % and 2.96 %, respectively.