Failure of a portion of a mine waste pile motivated a study to identify remaining portions of the pile that were unstable and to suggest appropriate, remedial stabilization efforts. Data collection focused on the principal parameters that control stability, namely, pile geometry and material strength. Data from a topographic survey of the pile and the interpolated bedrock surface under the pile were used to characterize the slope of the mine waste pile and the thickness of the waste material. Strength data were obtained from conventional, small-scale laboratory test methods and a large-scale test method that was used in the field and the laboratory. The small-scale tests, which did not include the relatively coarse fraction of the mine waste material, tended to overestimate the strength of the waste pile material. Strength and pile geometry data were combined in a GIS-based model that provided a first-order, conservative estimate of the stability of the pile based on the infinite slope method. Results from this model indicated three potentially unstable areas. These areas were analyzed using the method of slices. A single location on the pile was found to have an unacceptable factor of safety. A simple grading plan to remediate the problematic location was developed.

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