A method is described for inhibiting the production of acid mine drainage from the disposal of sulphide tailings and waste rock deposition during mining and milling of sulphide containing ores, which comprises adding to said sulphide tailings or waste rock deposition an effective amount of 2-mercapto-1-methyl imidazole or a 1,3,4-thiadiazole selected from the group consisting of 2,5-dimercapto-1,3,4-thiadiazole and 5-amino-2-thiol-1,3,4-thiadiazole to inhibit oxidation of sulphides and thereby prevent the formation of acid mine drainage.