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<br />is the potential for renewed instability in this drainage as mining and road construction <br />disturb the head of it? Why couldn't Pond 11 be accessed from Grassy Creek? <br />48. Stabilities and factors of safety calculated for haul roads assume there will be no seepage <br />encountered in the cuts or beneath fills. Test holes were drilled in October 1993, a very <br />dry period. Attachment 13-5 warns that the risk of slope instability will be "significantly <br />increased" if seepage 'is encountered. What data exists to determine the potential for <br />seepage to occur m haul road cuts during wet seasons and spring runoff? The Division <br />~ concerned that there is a real potential for some groundwater to occur in the haul road <br />cuts, at least during certain times of the year. What factors of safety will result from the <br />assumption that some groundwater can be expected at certain times of year? What <br />additional measures may be required to stabilize cuts and fills if groundwater is present? <br />Tab 15 -Hydrologic Monitoring Plan <br />49. Page 19 (Table 15-7): It does not appeaz that SCC intends to include the first aquifer <br />below the coal seam to be mined in its ground water monitoring plan. The first aquifer <br />below the coal seam to be mined (presumably the Trout Creek Sandstone) should be <br />included in the ground water monitoring plan to detect potential impacts and to verify <br />SCCs prediction of a negligible impact. <br />50. Page 21: SCC proposes discontinuing monitoring of groundwater in the Wolf Creek <br />Underburden. However, one miningg area will be located in the Wolf Creek Coal, and <br />the groundwater in the Wolf Creek Underbwden has a potential for impacK. Therefore, <br />groundwater monitoring in the Wolf Creek Underburden should resume prior to mining <br />the Wolf Creek Coal. <br />Tab 16 -Protection of the Hydrologic Balance <br />51. Page 4 notes that water from sedimentation onds may be used for dust suppression. <br />Has SCC secured the necessary water rights for this use? <br />52. Attachment 16-1: Water Rights Investigation and Plan for Augmentation has not been <br />submitted. Please provide ee copies of the attachment for Division review.. <br />53. Attachment 16-3, Alluvial Valley Floor Investigation, contains information that appears <br />contrary to information provided in Tab 10. For Armand Draw, the information in <br />Attachement 16-3 is that there aze no subirrigated areas in crop production. Exhibit 10-1 <br />shows "Improved Pasture, Subirrigated" in the vicinity of Pond 10 which is located in <br />Armand Draw. Please explain this apparent discrepancy. <br />Tab 17 -Probable Hydrologic Consequences <br />54. Page 2: The list of assumptions for the McWhorter pit inflow analysis includes an <br />assumption (#7) that there is no additional flow from the reclaimed spoils after the first <br />year. How does SCC justify this assumption when the development of spoil springs is <br />predicted? <br />55. Page 7: Is SCC assuming that the regional gradient is zero, or is the example given solely <br />for the purpose of illustration? <br />56. Page 10: Please provide, in the permit application, the calculations to show how the wet <br />pit area was arrived at for the Theis analysis. <br />M. Altavilla and G. Wendt 10 January 27, ]995 <br />