Electromagnetic Conductivity Surveys to Identify Acid Sources and Flow Patterns in U.S. Surface Coal Mines.
Watzlaf GR; Ladwig KJ
Proceeds: Acid Mine Drainage Seminar Halifax Nova Scotia 3/23- 26/87 Env Canada Pp187-213 :27 pages
An electromagnetic induction (emi) method of measuring earth conductivity was applied at several backfilled surface coal mines to determine the utility of this method for acid mine drainage (AMD) assessments. The method was found to be a quick, useful tool for subsurface characterization, which is necessary for the design of effective at-source AMD abatement strategies. Survey results and interpretations along with the results of confirmatory drilling are presented. The emi method delineated major subsurface anomalies such as disturbed rock-undisturbed rock interfaces (highwall, sidewall, and low wall), variations in the mine floor, and changes in the saturated spoil thickness; such information facilitates mapping of generalized flow patterns. Localized zones of highly pyritic material were easily observed as high-conductive anomalies. The degree to which emi data could be interpreted was site-specific and dependent on total thickness of backfill, relative thickness of saturation zone, and electrical properties of the backfill.
Proceeds: Acid Mine Drainage Seminar, Halifax, Nova Scotia, 3/23- 26/87. Env. Canada, Pp187-213