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• mesh, additional benches, rockfall fences or moving auger mining activkies back from the slope will need to be considered for this area. Colowyo and the auger mining contractor will need to evaluate conditions to determine the alternative or combination of alternatives to provide the level of risk acceptable to both parties. We can provide addtional recommendations as conditions become more apparent. According to Colowyo representatives, no previous underground mining is known in the West Pit or Streeter Pit areas. Previous testing during auger mining of the C-Seam and E-Seam in the East Pit did not indicate significant methane concentrations. As a precaution, we recommend methane measurements be performed daily at the active auger opening during operations in each seam using MSHA approved devices and procedures. Hydrologic Impact • Groundwater is not anticipated in the X, C, D or E-Seams. Occasional seepage into the auger openings may occur but significant flows or impacts on groundwater conditions in the area are not anticipated. Angering will primarily be performed down dip, with a flat dip anticipated along the east and west walls of the West Pit. The angering should have no net effect on seepage which enters the reclaimed pit. Water which enters through auger holes would likely have seeped through the coal seam in eRher case and no net effect on water volume or quality is anticipated. Spontaneous Combustion In our opinion, the risk of spontaneous combustion is considered low. The best evidence is that there have been no significant occurrences of spontaneous combustion of exposed coal seams over the operating fife of the mine. The auger openings will be exposed for periods estimated to be on the order of 6 to 8 months, • possibly extending to a year or two. Where angered areas will be uncovered for longer periods of time, monitoring is recommended. Contingency plans to excavate COLOWYO COAL COMPANY, L P. CTLR 23.585 9