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logical vehicle for this information. As Colowyo will not be reclaiming any acres in the South Taylor <br />area until near the end of mining activities there, the topsoil resource will be completely documented <br />well before any topsoil placement activities will be required. Table 2.05-1 could be updated during <br />permit renewals for example. <br />3. The amended reclamation plan includes discussion of variable topsoil replacement thickness as a major <br />element to enhance vegetative diversity and woody plant density on the reclaimed landscape. Amended <br />narrative correctly notes that relevant Federal rules [30 C.F.R. 816.22(d)(1)(i)] were recently amended <br />to explicitly allow for replacement of variable topsoil thicknesses, to the extent that such variations help <br />meet the specific revegetation goals identified in the permit. The corresponding State rule [4.06.4(2)(a)] <br />has not been revised, and specifies that topsoil and other [plant growth] materials shall be redistributed <br />in a manner that: <br />achieves an approximate uniform, stable thickness consistent with approved postmining <br />land uses, contours, surface water drainage systems and requirements of the vegetation <br />proposed to be established. <br />The Division has interpreted this rule as allowing for planned variation in topsoil replacement thickness <br />when the postmining land use is rangeland or wildlife habitat. The rationale for variable replacement <br />thickness is to more closely reflect the variation in topsoil thickness and substrate conditions that existed <br />prior to mining, to favor the establishment of particular vegetative life forms or community types, and to <br />enhance the potential for increased vegetative diversity on the reclaimed landscape. <br />These concepts were discussed among Colowyo, the Division, and CDOW on various occasions and <br />within numerous items of correspondence. There was general agreement that the amended reclamation <br />plan should identify site locations where thin topsoils would be replaced, to favor sagebrush and certain <br />other shrubs and native forbs, due to fact that faster growing grasses typically thrive at the expense of <br />shrubs, when relatively deep, uniform topsoils are replaced over large expanses. Replacement of <br />extremely thick topsoils in selected sites conducive to the establishment of aspen woodland and <br />associated tall shrubs was also discussed. Replacement of a range of varying topsoil thicknesses over <br />the landscape was viewed as an important strategy for achieving vegetative diversity on the reclaimed <br />landscape. <br />The general concepts were included in various sections of the amended text, but further refinement and <br />specificity is warranted, to move from conceptual discussion to enforceable commitment, appropriate for <br />inclusion in a permit. The Division has the following requests regarding topsoil replacement plans. <br />a) In the Supplemental Introduction beginning on page 2.05-42, there is a list of 14 measures that would <br />be implemented or considered to facilitate the establishment of a sagebrush grassland community. <br />Several of the measures relate to variable topsoil replacement, including construction of snow catchment <br />berms, placement of thin layers of topsoil, and possible placement of thin layers of overburden over <br />topsoil. Following the itemized list is the following statement. <br />The primary `foundation building" element for this approach is the ability to replace <br />variable topsoil depths and/or quality of soil materials depending on site-specific needs, <br />the discretion of the field construction supervisor, and the capabilities (or lack thereofi of <br />available materials and equipment.