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Nomination for 20th Anniversary Excellence in Surface Coal Mining Reclamation Awards April, 1997 Site Description Trapper Mine is a surface coal mine located approximately 6-1/2 miles south of the city of Craig, CO, along the northern slope of the Williams Fork Mountains. The climate is semi-arid steppe and is characterized by cold winters and moderately warm summers. The average annual precipitation is 13.9 inches, one-third of which falls in the form of snow and is the principal source of stream flow for the region. Soils are generally deep and formed in alluvium and colluvium derived from sandstone and shale. The topography is described as rolling hills with relativity steep slopes (average - 14%). The prevalent vegetation type is mountain shrub which interfaces with stands of big sagebrush at lower elevation and aspen types at higher elevations. General Introduction Mining operations commenced at Trapper in the late 1970's. Mining is accomplished with three Page 752LR draglines which typically operate in three active pits along the north flank of the Williams Fork Mountains on slopes which average approximately 14%. All of the coal currently produced at Trapper is delivered to the adjacent Craig Generating Station which provides electricity to the residents o(six states. Reclamation activities are particularly challenging at Trapper as a result of the steep slope conditions under which we operate. Notwithstanding these difficult mining and reclamation conditions, all of the Trapper rangelands reclaimed to date are topographically diverse, erosionally stable and either already are or soon will be characterized by a stable, diverse plant community of adapted, primarily native grass, forb and shrub species. Post-mining use of reclaimed Trapper lands is also enhanced through the use of innovative wildlife mitigation techniques as described in this paper. Sediment and Erosion Control Measures Introduction During surface mining activity, drainage systems are altered in that natural bedrock drainage control is often replaced with unconsolidated spoil material that is relatively homogeneous in nature. The fractured spoil material may produce a modification to what would naturally develop in terms of drainage pattern or hillslope and channel gradients. To compensate for this geologic change, hillslopes and channel gradients could be reduced or appropriate conservation techniques could be incorporated to reduce the potential for accelerated erosion. Trapper began in 1987 an accelerated program to control runoff and minimize the sedimentation problems that were caused by high rates of erosion, particularly in postmine drainageways. A variety of erosion control materials and methods have been evaluated and implemented since that time for the stabilization of reconstructed drainageways. Additionally, sediment reducing landforms and adapted plant materials have been used to control erosion on reclaimed sideslopes. This section presents the results of a sediment and erosion control program implemented from 1987 through 1996 and describes viable conservation allematives for successfully achieving sediment and erosion control on drastically disturbed lands in a cost effective manner. Erosion Control Strateeies A wide variety of soil erosion control materials, methods and sediment reducing measures have been used in reconstructed drainageways, on reclaimed sideslopes and on regraded spoils. The following list of measures has been tested for effectiveness in decreasing accelerated erosion, reducing flow rates and in reducing sediment loading in downstream sedimentation structures. Dozer Basins. Dozer basins (secondary sediment control basins typically smaller than one acre-foot in size) are constructed to trap and store sediment on disturbed areas to reduce or abate sediment loads. Basins are used to prevent the siltation of diversions, waterways, livestock ponds, and streams; to trap sediment originating from the active mine site and to prevent undesirable deposition on undisturbed bottomlands and reclaimed areas.