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<br /> <br />the overburden, although little information has been provided relative <br />to possible variations in chemistry within the overburden. Revised <br />Maps 7a-13a, ISa, 42a, Tables 4.5.73, and exhibits 23 and 24 were re- <br />submitted by Xerr Coal. <br />2. MLRD questioned whether the stratum labelled "Shale with Interbedded <br />Sandstone" could be specifically identified on a geologic crossection <br />which would show the Zocation of the sandstone strata. However, Itthologic <br />logs of the new core sites did not show an identifiable pattern because <br />the sandstone layers were too thin. <br />3. Revised cadmium and SAR averages were resubmitted using a more accurate <br />weighted average. MLRD was concerned that moderately high SAR values <br />of the spoil would affect revegetation in the Pit No. I area. The issue <br />was resolved by salvaging additional suitable subsoil to act as a buffer. <br />See X. Topsoil. <br />She proposed operation is in compliance. <br />V. Hydrologic Balance: Surface l9ater (7.04.5, 2.04.7, 2.05.3(4), 2.05.6(3), 4.05) <br />The following problems were identified in the review and have been satisfactorily <br />resolved. <br />1. Ditch Designs: <br />a. Minor modifications to the ditch locations were made to reduce the <br />amount of riprap needed and to insure a more stable channel. <br />b. Additional information on energy dissipaters had to be submitted. <br />c. Peak flow calr_ulations for Ditch M1 had to be revised to correct <br />an error in computing SCS curve numbers. <br />d. Because ditches were designed using vegetated lining conditions, a <br />question was raised as to what would be the flow velocities of the <br />ditches in the unvegetated state. Submission of revised velocities <br />verified that the ditches velocities are acceptable. It was agreed <br />that the Division would inspect the ditches for signs of erosion and <br />Kerr Coal would do any needed maintanence on the ditches. <br />2. Pond Designs: <br />The Division required additional information on emergency spillway design <br />and stability, embankment slopes, freeboard, cutoff trenches, stability <br />of the embankments, spillway locations, short circuiting baffles, and <br />pond location maps. Because of revised ditch locations it was decided <br />that a proposed diversion dam would be excluded from Watershed I while <br />retaining Ditch I1 and Pond2. Kerr Coal responded by resubmitting <br />necessary designs in Exhibit 42. <br />The following issues were raised in the review and require a stipulation for permit <br />approval: <br />1. In comparing design ditch grades with the proposed ditch location on Map <br />16a it was found that the ditch grades on Map 16a were higher than the <br />design grades in the test. In light of this discrepancy the following <br />stipulation is necessary: <br />KERR COAL IS REQUIRED TO CONSTRUCT ALL DITCHES USING THE DESIGN GRADES <br />RATHER THAN THE GRADES SHOWN ON MAP 16a. IF THIS REQUIRES RELOCATING <br />-4- <br />