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• Other Coal Company Standards <br />HWEC contacted three different coal companies located in northwestern <br />Colorado and found that one accepted the species diversity standard as <br />stated, another proposed a modification to the standard but was not <br />approved as yet and another did not include a standard but has not yet <br />gained approval. The company accepting the standard indicated that in <br />their premining data the six dominant species comprised 45% of the <br />composition and they felt that their reclamation would have no problem <br />meeting the species diversity requirement. The second company used a <br />modified approach by combining premining data from several plant <br />communities and composing an artificial plant community based upon several <br />plant communities. They then proposed that the four dominant herbaceous <br />species combined would not exceed 60% and that no one would exceed 40 <br />percent. <br />RECOMMENDATIONS <br />• HWEC recommends based upon the information presented in this report <br />that the species diversity stipulation be modified to read, "the 5 <br />herbaceous species combined will not exceed 90% in relative cover or <br />production and any one of the 5 species will not exceed 60% in relative <br />importance." These percentages were selected based largely on the <br />premining reference area data and supported by the literature. The 5 most <br />dominant species in the reference areas studied at the Orchard Valley Mine <br />approached 90% relative cover with 83.2, 92.1 and 89.5 percent. Single <br />most dominant species in the reference areas were 65, 20 and 42 percent <br />relative cover. Two of which exceeded the CMLRD recommendation. <br />The Orchard Valley Mine is situated in an ecologically harsh <br />environment being on a steep, south and west facing exposure. Typically, <br />the diversity of species in harsh environments is low; the landscape being <br />dominated by relatively few species. We feel that the primary concern in <br />the rehabilitation of the Orchard Valley Mine is to stabilize the slopes <br />with a mixture of species best suited to accomplish the stabilization. We <br />feel that the proposed modification to the stipulation will best accomplish <br />• that goal. <br />7 <br />