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RECLAMATION - BENCHES <br /> mine bench space. The fill was probably built by end-dumping, without <br /> compaction and without foundation preparation. Fills are thus at an angle <br /> close to the angle of repose. Tension cracks may indicate potential stability <br /> problems. Erosion, gullying, rilling and sloughing of the fill surface are <br /> common. <br /> The reclamation concept is to flatten the upper portion of the fill to a slope of <br /> 1.5:1 or flatter. <br /> High Thin Fill <br /> • High thin fill is typical for nearly all mine benches. Material from the mine <br /> bench excavation was end-dumped on a steep slope, formed by either rock <br /> outcrops or occasional patches of colluvial soils or talus deposits, below the <br /> bench. The fill can be classified as a spoil deposit; it does not comprise a <br /> structural fill (thickness is limited to several feet only). The natural slopes <br /> below the fill are frequently steep (300- 400), locally steeper than angle of <br /> repose of the fill. There is no danger of a large-scale failure; sloughing and <br /> erosion are the most important stability problems. <br /> The reclamation concept is to minimize erosion and sloughing potential by <br /> eliminating the sharp crest of the fill and by improving the surface drainage <br /> so as to prevent surface water entering the fill. <br /> TEST PLOTS <br /> Test sections were established to determine whether these reclamation <br /> concepts would be suitable. In 1984, Mid-Continent prepared four test sections <br /> near No. 4 Mine Bench to test the reclamation concepts. <br /> In November, 1987 the test sections were examined and photographed. The <br /> results were submitted in a report of January, 1988, prepared by Scott Jones, <br /> P.E., and Bruce Collins, Ph.D. geologist. <br /> In addition to the three reclamation concepts, as described, a test plot was <br /> established to test reclamation for areas of severe erosion. <br /> Test results for each concept indicated: <br /> Section 1. High Rock Cut. <br /> s <br />