ABSTRACT
Acid drainage production in mining environments, popularly known as Acid Mine Drainage (AMD), is attributed to pyrite oxidation. However, the natural geologic environment is made of many other minerals which may contribute to AMD production or may inhibit AMD production. Commonly, the minerals that are part of the natural geologic system, e.g., mine waste, and could be involved in AMD production/control include aluminosilicates, metal oxides, and organic matter. The manner in which the minerals could be involved in the production/control of AMD is mainly through the surface electrochemical properties. Seventy to eighty percent, by weight, of the organic matter found in most natural geologic material, for example, soils, and waters consists of humic substances. Humic substances are generally defined as condense polymers of aromatic and aliphatic compounds produced during decomposition of plant and animal residues and by microbial synthesis. Humic substances are complex compounds with various amounts and type of building units, functional groups, and structural units.
