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Post Mining Land Use <br />The post-mining land use for the Eastside Mine is undeveloped rangeland. The reclaimed lands <br />have vegetative cover composed of a variety of grasses, fortis, and woody shrubs. The <br />seasonality and forage characteristics ofthe vegetative species appear suitable for the approved <br />post-mining land use of undeveloped rangeland. No weed problems or significant bare areas <br />were found. <br />The vegetation cover on the reclaimed slopes appears to be preventing erosion. According to the <br />approved plan, slopes above the fan portal and on the hillsides were specified to be 30 to 38 <br />percent into the facility area. According to the operator's bond release application, the slopes <br />specified in the area in front of the portal and the collection ditch is graded from 8 to 20 percent. <br />The slope from the lower bench down to the reclaimed sediment pond is designed at 10.6 <br />percent. The regraded areas have slopes that comply with the plan specification or are slightly <br />flatter. These results were previously obtained by field measurements using an inclinometer and <br />by overlaying the "as-built" post-mining topography map over the proposed post-mining <br />topography map as described by the Bond Release application. No delta or sediment fans were <br />noted anywhere on the site during the final bond release inspection. No evidence of instability <br />on the reclaimed areas throughout the site was found. No tension cracks were found at the tops <br />of the slopes. <br />The revegetation success standards were based on what would be necessary for the land to <br />properly function as undeveloped rangeland. Based on the achievement of the requirements, the <br />Division finds that the revegetation on the Eastside Mine reclaimed areas is capable of <br />supporting post-mining land use. <br />Evaluation of Hydrolo~ic Impacts Required by Section 3.03.2(2) <br />Rule 3.03.2(2) requires the Division to evaluate hydrologic impacts prior to releasing reclamation <br />liability. This evaluation must consider whether pollution of surface or subsurface water is <br />occurring and the probability of future occurrence of such pollution. The Division's evaluation is <br />summarized below. <br />Ground Water Impacts <br />The underground workings of the Eastside Mine were developed within the approximately <br />20-foot thick E Seam of the Iles Formation. The Iles Formation is exposed at the land surface <br />at the Eastside location in the steeply dipping outcrop belt called the Grand Hogback. <br />Bedding at Eastside dips 70 degrees southwestward into the Piceance Creek Basin. The E <br />Seam is directly underlain by an aquiclude, the Mancos Shale, and is overlain by an aquitard, <br />the silty and clay-rich fine-grained sandstone of the Iles Formation. The aquitard and <br />aquiclude would prevent any significant amount of vertical migration of sumped water from <br />the workings through intergranular porosity. Subsidence fractures could provide an <br />interstratal migration pathway, but this method of migration would be of limited areal extent <br />Eastside Mine Page 8 October 31, 2007 <br />Phase III Bond Release <br />