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The reclaimed La Plata mine site is located approximately one-quarter mile, and directly <br />northeast of another reclaimed and revoked bond site -the Blue Flame Mine. At the <br />Blue Flame Mine (on anorth-facing slope) the revegetation cover standard is 30 percent, <br />the productivity standard is 500 pounds per acre, and the woody plant density standazd is <br />600 stems per acre. In contrast, the La Plata No. 1 Mine reclaimed site is situated on a <br />south-facing slope, meaning that warmer surface temperatures impact this particular site. <br />This site has less access to water infiltration due to evaporative losses and less surface <br />vegetation cover, in general. Additionally, the topography of the site is much steeper <br />than at the Blue Flame site, and has a rockier composition. These factors combine to <br />suggest that the La Plata site should have less vegetative success in establishing a diverse <br />and highly productive vegetative community than the Blue Flame site. <br />Based on the descriptions provided, the following revised revegetation standards for the <br />reclaimed La Plata No. 1 Mine site were established by CDMG: <br />• The minimum vegetative cover for this site will be 30 percent to reduce the erosion <br />potential of the steep and rocky terrain. <br />• Total production will be a minimum of 500 pounds per acre. <br />• Total stem density on a reclaimed site is often less than on mature woodland forest. <br />Shrub density will be at least 600 stems/acre. <br />• Species diversity is generally limited by diminished amounts of soil water on south- <br />facing slopes. Fortis are usually more impacted by any compounded soil moisture <br />reductions -such as the current drought conditions in Colorado. Both shrubs and <br />grasses have mechanisms to survive these conditions, while fortis aze more sensitive <br />to extreme reductions in moisture and will be represented less in cover sampling. <br />However, as the requirements of Rule 4.15.10(1) apply to the remaining areas of the La <br />Plata # 1 Mine (the area south of CR 120 was relinquished to the landowner a number of <br />years ago), the only applicable revegetation standard is that of vegetation cover. The <br />applicable requirement is that the "ground cover of living plants shall not be less than can <br />be supported by the best available topsoil or other suitable material in the reaffected <br />areas, shall not be less than the ground cover existing before redisturbance, and shall be <br />adequate to wntrol erosion." <br />2.5 Statistical Analysis <br />Evaluation of revegetation establishment and success was accomplished through a direct <br />comparison of the reclaimed area mean total vegetative cover with the reclamation <br />success standard. A Students t test was used for the statistical comparison. This is <br />consistent with the recommendations of the Division of Minerals and Geology in their <br />1988 Guidelines for Compliance with. Land. Use and_ Vegetation Requirements of the <br />La Plata # 1 Mine Page 4 <br />2003 Vegetation Sampling <br />