Anionic surfactants such as sodium dodecylbenzene sulfonate, sodium laurel sulfate, and others are effective in controlling acid production from sulfidic mate1ials such as overburden, coal, coal refuse, ores, waste rock, and tailings. Their use in practical mining and reclamation applications, however, is only being recently documented since longer term field data are only now becoming available. This paper describes three applications of bacterial inhibitors. The first is at a surface coal mine where special handling and bacterial inhibition have prevented acid drainage from highly pyritic (more than 0.5% pyrite, neutralization potential less than 30 st per 1,000 st of CaC0 3 equivalent, and net deficiency of neutralizers of 15 st per 1,000 st of CaC0 3 equivalent) dark shale overburden for over 2 yr. The second application is at an active refuse disposal area where alkaline addition at more than three times that indicated by acid-base accounting failed to control acid production in refuse with 13% pyritic sulfur and neutralization deficiency of 444 st per 1,000 st of CaCO, equivalent. Bacterial inhibitors were successful in reducing acidity and metals in site underdrain effluent by 88% to 90%. The third application was at a silver mine where waste rock containing up to 0.37% pyrite was treated with surfactant bactericides to reduce leachate acidity by 93% and sulfates by 70%.