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season graminids; Indian ricegrass, Crested wheatgrass, Thickspike wheatgrass, Slender wheatgrass, <br />Bluebunch wheatgrass, and a rush species (Juncus sp.). Of these 6 species, no one species exceeded <br />greater than 3% allowable relative cover, however, the sum of these cool season species accounted <br />for 4.5% allowable relative cover. Ten warm season species were encountered during sampling of <br />the Area 33 parcel. Four warm season grasses contributed greater than 3% allowable relative cover, <br />and only one, Prairie sandreed, contributed greater than 40% allowable relative cover. Prairie <br />sandreed tends to grow as a robust wide leaved grass. It is logical that encountering a Prairie <br />sandreed plant during vegetation sampling would result in a higher vegetative cover value than <br />sampling other species that tend to be low growing, smaller plants with narrower leaves. The good <br />representation of the other graminid species indicates that this reclaimed community is not <br />excessively dominated by a single species. <br />As stated before, species composition is not a requirement for Phase II bond release success. The <br />Division analyses the data to determine if the reclaimed communities are approaching the required <br />success standards prior to final bond release. The data presented for Area 31, 32, and 33 parcels <br />indicate that the reclaimed communities have not yet achieved the species composition standards but <br />area approaching the success standards. <br />The approved post mining land use is rangeland. The established species are appropriate and support <br />the post mining land use. Observation of Pronghorn antelope browsing in the reclaimed parcels <br />during the bond release inspection provides additional evidence that the established vegetation is also <br />beneficial to wildlife. There is no woody stem success requirement on the Keenesburg reclaimed <br />area, and noxious weed species were minimal with no obvious signs of infestations. The surrounding <br />area is prone to Cheatgrass infestation. CEC has implemented numerous different efforts to manage <br />Cheatgrass in the reclaimed areas in accordance with their approved weed control plan. <br />CEC used the Revised /Universal soil Loss Equation (RUSLE) to demonstrate acceptable soil loss on the <br />reclaimed lands. The Division has previously approved CEC's use ofthis model to demonstrate acceptable <br />sediment solid demonstration. CEC used a 2 -year, 6 -hour Type II storm event to calculate the R factor in <br />the RUSLE equation. The 2 -year, 6 -hour Type II event for the mine area was 1.4 inches of rainfall. The <br />Division finds the use of this factor acceptable. CEC provided a figure showing how slope length and <br />gradient were determined. The cover factor was derived from 2018 cover and species measurements. <br />CEC's calculations determined that undisturbed area would contribute 0.061 tons /acre/year of sediment. <br />The reclaimed parcels were calculated to potentially contribute 0.043 tons/acre/year of sediment using the <br />same assumptions. The Division considers that demonstration acceptable and shows that the reclaimed <br />areas are projected to contribute less sediment than the undisturbed condition. The results of CEC's <br />calculations are found in Table 3 in the SL10 application. <br />Summary and Conclusions <br />Based upon a review of the mine permit, the applicant's bond release application, and site inspections, the <br />Division finds that Coors Energy Company has replaced topsoil in accordance with the approved <br />reclamation plan. Coors Energy Company has established vegetation which supports the approved post <br />mine land use and meets the approved success standard for vegetative cover. The Division finds that the <br />Keenesburg Mine C1981-028 SL -10 Page 7 of 9 <br />