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March 15, 2002 <br />Page 2 of 3 Pages <br />these areas appear to retain aspects still short of compliance with the rules. Areas proposed at <br />elevations below approximate original contour (such as the proposed West Pit Ditch and the <br />proposed topography of the NE'/4 of Section 9) preclude, by definition, permanent excess spoil <br />fills at elevations above approximate original contour (such as the upper reaches of the West Pit <br />Fill). Please address the Following items in a refined version of the proposed postmining <br />topography in these areas. <br />Item 1 Land Fonn Cross section B-B' of the application illustrates remnant vaziations between <br />premining and postmining land surface configurations, but the variances are better visualized by <br />across section along the trace Z-Z' on Drawings A and B attached. This trace begins, follows <br />and ends in vicinity of the following stations: <br />Station 1 E1350000 N337000 near north edge of Section 16 <br />Station 2 E1350000 N337000 head ofproposed West Pit Ditch <br />Station 3 E1349000 N339000 proposed topographic high <br />Station 4 E1352000 N344000 undisturbed ground elevation <br />Station 5 E1351000 N348000 face of West Pit Fill. <br />As introduced above, there aze three significant features along the trace that warrant additional <br />consideration. One is the topographic high between Stations 4 and 5, the upper portion of a <br />previously approved West Pit (excess spoil) Fill. Lowering of this topographic high from the <br />currently approved postmining topography by that proposed in the application is noted, but this <br />topographic high is still, by definition explained above, a significant variation from original <br />contour. Two regions of insufficient backfill demonstrate that this topographic high does not <br />consist of "excess" spoil. The more significant region of insufficient backfill is that of the <br />proposed West Pit Ditch (vicinity and west of Station 2). This feature does not appear in the <br />premining topography or the currently approved postmining topography. The other is a broader <br />region located in the NE'/< of Section 9, and is illustrated on the Premining Topography vs TR 56 <br />PMT isopach drawing provided by Colowyo in support of this review. <br />Premining topography along the trace Z-Z' was a nearly constant 7.6% slope, north-facing slope <br />with no changes from negative to positive grades. The proposed topography along the trace <br />introduces a 15%north-facing slope down (the south side) to the West Pit Ditch thalweg (28% <br />slopes to the west), and asouth-facing 8% rise (15% slopes to the west) back up to an elevation <br />of 7700; thence a saddle as one approaches Station 3 from Station 4, and a depression between <br />Stations 4 and 5 before reaching the proposed topographic high of the West Pit Fill. <br />Station 4 is an azea near premining elevations (an unmined region). The proposed elevations of <br />Station 3 are near premining elevations. Using these points as control elevations, filling of <br />depressions and lowering of high ground (southern highs of the West Pit Fill) would better <br />approximate original contour (reestablish the constant scopes of premining topography). <br />Item 2 Drainage Pattern Of lesser signiffcance is the proposed orientation of the West Pit Ditch <br />and the replacement by this feature of two drainages off the reclaimed area to East Taylor Creek <br />