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Best Practices in Abandoned Mine Land Reclamation <br /> Best Management BMP#4-EROSION CONTROL BY REGRADING Regrading generally requires the use of heavy <br /> Practices Applicable situations construction equipment, such as bulldozers, <br /> waste rock piles scrapers, loaders, backhoes and excavators to <br /> mill tailings fill the holes and grade the slope. Note that <br /> the surface of the final slope should be <br /> Description and purpose moderately roughened to help in establishing <br /> Erosion occurs as a result of many things vegetation, but not so rough as to promote <br /> including water,wind, frost and animal action. pooling of water. <br /> Generally slopes with less than three feet hori- <br /> zontal to one foot vertical are stable from <br /> erosion and conducive to vegetation growth. When to do it <br /> The optimum time to construct this BMP is <br /> Often an area that has been barren for a long during the driest time of the year (generally <br /> time is highly dissected by water erosion and late summer or fall), simply for ease of con- <br /> may be susceptible to wind erosion and frost struction. Experience shows that wet tailings <br /> action.An area such as this requires regrading are not conducive to heavy equipment traffic. <br /> to make the surface more uniform and gently <br /> sloping. <br /> Considerations <br /> This BMP is generally followed by vegetation <br /> Horn to do it of the waste rock or tailings if the waste rock or <br /> Because the ultimate goal is to have a gently tailings is not too toxic and can support the <br /> sloping surface, natural debris, such as tree establishment and growth of vegetation (see <br /> trunks and stumps, and metal debris should BMP#6). In cases in which the waste rock or <br /> be removed prior to regrading. If the natural tailings is toxic and cannot support vegeta- <br /> debris is regraded into the new slope, the dirt tion, regrading is followed by capping and <br /> above the debris will settle as it decays and vegetation(see BMP#5 and 6). <br /> could leave a hole or low spot allowing water to <br /> pond. Pooled water can seep in and leach The potential for erosion can be reduced by <br /> through the reactive waste rock or tailings,and creating grooves across the slope(or perpendi- <br /> result in acidic drainage with high metals con- cular to the slope direction).This can be done <br /> tent being discharged into the surrounding easily on the last pass of the heavy equipment <br /> environment. <br /> a tea. +►r <br /> .t <br /> fi_ s <br /> i <br /> MIRED DOWN IN WET TAILINGS! NEWLY-RECLAIMED SLOPE ROUGHENED TO <br /> HELP IN ESTABLISHING VEGETATION <br /> 20 <br />