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Performance Standards. Comment: Item t Land Form Cross section B-B' of the application illustrates remnant variations between premining and poslmining land surface configurations, but the variances are better visualized by across section along the trace Z-Z' on Drawings A and B attached. This trace begins, follows and ends in vicinity of the following stations: Station 1 E1350000 N337000 near north edge of Section 16 Station 2 E1350000 N337000 head of proposed West Pit Ditch Station 3 E1349000 N339000 proposed topographic high Station 4 E1352000 N344000 undisturbed ground elevation Station 5 E1351000 N348000 face of West Pit Fill. As introduced above. U,ere are three s,yn,f;cant features along the trace that warrant additional consideration. One is the topographic high between Stations 4 and 5, the upper portion of a previously approved West Pit (excess spoil) Fill. Lowering of this topographic high from the currently approved postmininy topography by that proposed in the application ~s noted. but this topographic high is stdi. by definition explained above, a signfcant vanat;on from original contour. Two regions of insufficient backfill demonsUate that this topographic high does not consist of "excess" spoil. The more significant region of insufficient backfill is that of the proposed West Pit Ditch (vicinity and west of Station 2). This feature does not appear in the premining topography or the currently approved postminuTg topography The other is a broader region located In the NE'/. of Section 9, and is illustrated on the Premining Topography vs. TR 56 PMT isopach drawing provided by Colowyo in support of this review. Premining topography along the trace Z-Z' was a nearly constant 7.6% slope. north-facing slope with no changes from negative to positive grades. The proposed topography along the trace introduces a 15% north-facing slope down (the south side) to the West Pit Ditch thalweg (28% slopes to the west), and asouth-facing 8% rise (15% slopes to the west) back up to an elevation of 7700; thence a saddle as one approaches Station 31rom Station 4, and a depression between Stations 4 and 5 before reaching the proposed topographic high of the West Pit Fill. Station 4 is an area near premining elevations (an unmined region). The proposed elevations of Station 3 are near premining elevations. Using these points as control elevations, filling of depressions and lowering of high ground (southern highs of the West Pit Fill) would better approximate original contour (re-establish the constant slopes of premining topography). Response: Colowyo has noted your concerns for these areas of higher or lower elevations relating to the approved PMT. As you are aware in our re-evaluation of the volumetrics for PMT we determined that there was a "bust" in the model leaving the actual backfill material 30 million yards short. Therefore, all proposed designs in this TR-56 are not going to be able to meet PMT contours already approved. However, every reasonable and practical effort has been implemented to re- design for AOC in order to meet drainage patterns, slopes. slope aspect, etc. When you assess where Colowyo is in their backfilling program presently, you can see that there will be significant adjustments made in order to meet this proposed PMT. Common and usual trucklshovel activity will not meet this design. Instead, special set-up and hauling will be necessary to excavate and haul material to meet this PMT design. As menGOned, Colowyo has made adlustments in this design based on CDMG recommendations. For instance, in the earlier versions of Colowyo's TR-56 submittals, we CFa 1 2 7 Tk-5o