841350 Earth resistivity investigations in reclaimed surface lignite mine spoils : Kehew, A E; Groenewold, G H US Bureau of Mines reportOFR73-83, Nov 1982, 98P

Abstract

Earth resistivity surveys using the Wenner electrode configuration were made in unmined areas and reclaimed spoils at three surface lignite mines in western North Dakota. The study sites were the Center, Indian Head, and Falkirk Mines. Automatic interpretation of the curves was accomplished with the method of Zohdy and Bisdorf (1975). Overburden materials become more homogeneous with respect to resistivity during the mining and reclamation process. The spoils curves show localized heterogeneities probably related to discontinuous moisture content variations in the spoils. Consistent resistivity differences in spoils occur between mines with overburdens of different mineralogic compositions. Groundwater chemical composition in terms of total-dissolved-solids (TDS) is inversely correlated (r = -0.61) with apparent resistivity at the 80-foot spacing from a survey centered at a piezometer screened near the base of the spoils. Better inverse correlation is probably prevented by high variability in TDS within the spoils groundwater. A useful predictive relationship may be the plot of mean apparent resistivity at the 80-foot spacing for an entire mine against mean TDS for all wells in spoils at that mine.