Abstract: The leaching of metals from waste rock is retarded by coating the waste rock with a polymer that both adheres to the rock and chemically binds with the leaching metals. In some cases, the pH of the waste rock environment must be increased prior to polymer treatment with an addition of a neutralizing agent such as lime. Specifically, this neutralizing agent raises the pH of the waste rock environment thereby allowing the polymer to hold this neutralizing agent within the waste rock.

Abstract: Mine waste water is treated to remove both dissolved and particulate metal values by an improved process, the process comprising:A. Mixing with the mine waste water a sufficient amount of anionic polymer to combine with the dissolved and particulate metal values to form a polymer/metal particle complex,B. Mixing the polymer/metal particle complex of Step A with a source of ferric ions, e.g. ferric chloride, to form a ferric/polymer/metal particle complex,C. Mixing the ferric/polymer/metal particle complex of Step B with a source of hydroxyl ions, e.g. a solution of calcium oxide, to form a hydroxylated ferric/polymer/metal particle complex,D. Mixing sufficient flocculent, e.g. a polyacrylamide, with the complex of Step C to precipitate the complex, andE. Separating the slurry of Step D into a clean water effluent and a high density (e.g. >50% solids), low toxic sludge.