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sheet flow from the topsoil surface. Due to the specific equipment used for the Sagebrush <br />Steppe areas, topsoil will be left in a more smooth condition to ensure proper seeding depth <br />as described in the text. Any topsoil put into final position with a dozer will by practice be in <br />a state of rough condition. Previous roughening efforts at Colowyo have been extreme, <br />leading to difficulties in placing seed at biologically viable depths. The addition of more <br />contour ditches will reduce sheet flow and moderating the roughness will allow a greater <br />percentage of seed to germinate and provide ground cover that will also alleviate rilling and <br />sediment control issues. As Coloywo transitions into areas of steeper slopes, density of cross <br />ripping will be tightened to increase surface roughness and more contour ditches will be used <br />to break up the slopes and minimize sheet flow conditions and reduce any concentration of <br />flow from rain/snowmelt events. Seedbed preparation, other surface manipulation practices <br />and seeding will be completed primarily during the fall months. Contour furrows, <br />approximately 2 -3 feet deep at the deepest point and 6 -10 feet wide, which have been used on <br />slope areas very successfully during the past several years, will be used to reduce erosion <br />potential, conserve moisture, and maintain site stability until vegetation is sufficiently <br />established. The contour ditches will be surveyed and staked on contour at a grade of 1 %, <br />and shall be constructed using a D6 dozer. Distance between ditches will vary. Small rock <br />check dams may also be used where appropriate to aid in control of erosion both prior to <br />seeding and if necessary, after an area has been seeded. <br />Given recent changes to Federal legislation (30 C.F.R. §816.22(d)(1)(i)) as published in the <br />Federal Register (August 30, 2006, - pages 51683 - 51706), mine operators are now allowed to <br />use "non- uniform redistribution of topsoil in their reclamation plan to encourage plant <br />diversity...." Furthermore, the Colorado Division of Wildlife has requested Colowyo replace <br />topsoil in a non - uniform manner as indicated by their statement: (see complete CDOW letter in <br />Section 4.15.8) <br />"DWM Wangnild discussed the possibility of changing reclamation efforts in the <br />new [South Taylor] permit area. Specific changes would ideally be focused on <br />dramatically varying topsoil depths in an effort to mimic natural depths and thus <br />provide more suitable environments for woody species establishment. One <br />example of this would be to create some sites with extremely shallow topsoil <br />designed at reducing grass stand establishment and their resulting competition <br />with shrubs for water and soil nutrients. Another example would be to create <br />other sites with extremely deep topsoil depths. These sites would ideally benefit <br />woody species like aspen and chokecherry." <br />In this regard, and depending on site - specific opportunities, Colowyo will utilize the planned <br />post -mine topography (PMT) to help identify candidate (and prime candidate) areas for targeting <br />Sagebrush Steppe post- mining communities. Key to this analysis will be considerations for the <br />risk of erosion and for long -term stability. One such "threshold" value to be used for this analysis <br />will be a slope break at 10% gradient. Slopes greater than 10% will be considered too risky to <br />make attempts at targeting shrub communities, largely due to snowpack runoff scenarios that can <br />often lead to serious erosion and stability failures. For example, snowmelt runoff in the early <br />1980s caused widespread and severe down - cutting of the natural drainages to the immediate west <br />of Colowyo. Unless proven otherwise by hydraulic and/or erosion modeling, slopes less than <br />10% will be identified as candidate locations for shrub community establishment. Another <br />"threshold" value to be used in the PMT analysis is the size of units that may exhibit slopes 10% <br />or flatter. Areas small in aerial extent (e.g., less than about 5 acres) will not be identified to <br />receive shrub- conducive metrics. Only those areas that are larger will be identified. The exact <br />2.05 -30 Revision Date: 8/10/10 <br />Revision No.: TR -87 <br />