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and gully formation. Hillslopes did not show significant down-cutting from concentrated <br />flow, even on the steepest slopes in the former office azea. No delta or sediment fans were <br />found. No evidence of instability on the reclaimed portal bench or former office azea was <br />found. No tension cracks were found at the tops of the slopes and no compression bulges <br />were evident on slopes. The bond release area's requirements for vegetation production and <br />species diversity were based on what would be necessary for the land functioning as grazing <br />and wildlife habitat. The bond release area has met those requirements. Based on the <br />achievement of those requirements, and the observed successful livestock grazing and <br />wildlife use on the site, the Division fmds that the revegetation on the bond release blocks <br />is capable of supporting the postmining land use. <br />Post-Mining Sediment Yield <br />Premising sediment yield at the Apex Mine is unknown because of pre-law disturbance. Sunland's <br />submittal for Technical Revision TR-12 contains apost-mining calculation for the disturbed azea <br />using the Revised Universal Soil Loss Equation (RUBLE). The calculation used reasonable values <br />for variables. It is reasonable to believe the post-mining sediment yield at the Apex Mine is no more <br />than the premising yield because the post-mining RUSLE calculation indicates sediment yield from <br />the site of 0.43 tons per acre per yeaz, a low yield for rangeland in northwest Colorado. With the <br />exception of one small area on the site, all drainage from the 4.5-acre disturbed azea is touted <br />through the pond. The pond has not dischazged for several yeazs, indicating a low post-mining <br />sediment yield. Based on the foregoing observations, the Division fmds that the lands proposed for <br />Phase II bond release are not contributing suspended solids to streamflow or runoff outside the <br />permit area in excess of premising levels. <br />Evaluation of Hydrologic Impacts <br />The Division has reviewed the predicted and observed hydrologic impacts caused by the Apex Mine. <br />These impacts are described in Sunland's bond release submittal, the Probable Hydrologic <br />Consequences section of the permit application, and in annual hydrology reports submitted by <br />Sunland. All of the observed impacts aze consistent with those predicted in the Probable Hydrologic <br />Consequences section of the permit application and the Division's Yampa River Cumulative <br />Hydrologic Impact Assessment. The Division's review identified the following hydrologic impacts. <br />Ground Water Impacts: <br />The Division conducted a detailed analysis of potential ground water impacts at the Apex <br />Mine in a review of the 1999 annual hydrology report. The results of the analysis are <br />described in a memo to the annual hydrology report file dated November 29, 2000. <br />The Apex No. 2 Mine workings probably aze filling with the water that seeps into the <br />mine from bedrock in the floor, walls, and roof of the workings. The water will probably <br />fill the workings to a maximum elevation of about 7350 feet during the next 30 years, <br />Apex No. 2 Mine Page 11 January 24, 2003 <br />Phases I, II, and III Bond Release <br />