Application of Acid-Base Analysis to Wastes from Base Metal and Precious Metal Mines

Acid-base analysis is used to assess the potential for waste materials to generate acid when exposed to an oxidized leaching environment.Even though the procedure was initially developed for coal mine overburden and reject, it has become widely accepted as tool in the assessment of waste rock and processing wastes from base metal and precious metal operations.This paper examines the applications of the acid-base analysis to non-coal situations based on the authors' direct experience at more than 30 base metal and precious metal projects in Australia, New Zealand and Papua New Guinea.The fundamental principles of the technique are outlined and the major potential pitfalls in interpretation and use of acid-base data are described.The paper concludes that the acid-base technique is an essential tool for the assessment of waste characteristics as well as being suitable as a monitoring procedure at non-coal mines.However, the interpretation of results is site-specific and requires detailed geochemical investigation to provide the understanding and data base for this interpretation.