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Drainages are constructed with gradients similar to those originally present, and complement the <br />drainage pattern of the surrounding terrain. Pre - mining and pos- mining drainage profiles are <br />found on Maps 33, 33A and 33B. <br />Final grading plans provide a surface that both minimizes erosion and slippage following the <br />placement of topsoil. Final slopes, in general, do not exceed one vertical to three horizontal <br />(lv:3h). <br />Stock tanks of less than two acre -foot in storage capacity and embankments of less than five feet <br />in height may be built and retained (following Division approval) to provide for the approved <br />post- mining land use. <br />Beginning in 1983, surveys were conducted to assure attainment of approximate original <br />contour. Survey results were submitted on a yearly basis as part of Colowyo's Annual <br />Reclamation Report. In 1987, this requirement was reduced to require survey reports only every <br />two and one -half years. In 1992, swell factor monitoring and analyses were terminated (Permit, <br />Page 4.14 -2). <br />D. Specific Findings Required by Section 4.14 <br />These specific findings are applicable to all areas of the Colowyo Mine including the East Pit, <br />West Pit, Section 16 Pit, the South Taylor Pit, and the Collom expansion area pits, Little Collom <br />X and Collom Lite. <br />1. The Division approved the retention of box cut spoil or initial cut spoil outside the pit <br />area since the Applicant has demonstrated that such material is not required to achieve <br />approximate original contour in accordance with Rule 4.09.1 [Rule 4.14.1(2)(d)]. <br />2. The Applicant demonstrated that fill proposed to eliminate the highwall and <br />depressions meets all the requirements of 4.05, 4.06, 4.09 and 4.15. Therefore, the <br />Division proposes that excess material not required for reclaiming highwalls and other <br />depressions need not be returned to approximate original contour [Rule 4.14.1(2)(a)]. <br />3. In order to conserve soil moisture, ensure stability, and control erosion on final graded <br />slopes, the Division approved cut - and -fill terraces. These terraces are compatible with the <br />postmining land use, and will meet all the requirements of Rule 4.14.2(2). <br />4. Permitted small depressions (less than two acre -foot of capacity, embankments less <br />than five feet in height) in the backfill are used to minimize erosion, create or enhance <br />wildlife habitat, conserve soil moisture, and promote revegetation. The Division <br />specifically approves each such small depression [Rule 4.14.2(3)]. <br />Colowyo Coal Mine C1981 -019 PR -03 59 April 10, 2013 <br />