Murdock, D. J., Fox, J. R. W., & Bensley, J. G. (1994). Treatment of acid mine drainage by the high density sludge process. In Special Publication – United States. Bureau of Mines, Report: BUMINES-SP-06A-94 (pp. 241–249). Proceedings of the International land reclamation and mine drainage conference and Third international conference on The abatement of acidic drainage; Volume 1 of 4; Mine drainage.