Laserfiche WebLink
usage in the mine vicinity. Review of data for the region indicates that <br />none of the other mines in the area have monitored the Rollins <br />Sandstone. Since the Somerset Mine has been active since 1906, any <br />potential for severe water quality impact would probably be evident by <br />this time. The water quality data for R-1, a well completed in Rollins <br />Sandstone and drilled by Mountain Coal Company in 1976, indicates <br />total dissolved solids generally outside the range acceptable for drinking <br />water. MCC has completed two wells in [he Rollins Sandstone to <br />monitor water levels and provide water quality data. Based on <br />information contained in the Annual Hydrology Reports prepared for <br />the mine, mining activities in both the F and B seams are thought to <br />have had no impact on groundwater in the Rollins Sandstone to date. <br />The majority of Mountain Coal Company's hydrologic monitoring <br />concentrates on mine water discharges and wells associated with <br />B Seam mining. Disturbances and changes to water quality, if [hey <br />occur, will be manifested in B Seam discharge water and B Seam <br />monitoring wells prior to any potential impacts to [he Rollins <br />Sandstone. The B Seam is separated from the Rollins by sil[stones, <br />shales, and another coal seam. It is unlikely that the Rollins Sandstone <br />would be used as a primary drinking water source because of its great <br />depth outside stream valleys and the ready availability of better quality <br />surface water near the stream valleys. <br />MCC has mapped the B Seam overburden thickness with potential areas <br />of groundwater inflow highlighted. These areas of potential inflows, <br />similar to the F Seam, are associated with fracture zones beneath <br />drainages and near outcrops and areas of low overburden. A map of <br />the potentiometric surface of the B Seam in the area near Jumbo <br />Mountain has been produced and can be reviewed in Exhibit 17A of the <br />permit document. <br />MCC has made inflow estimates for the B Seam mine plan for the <br />five-year permit area. The "probable maximum" estimate of mine <br />inflow shows a peak or initial inflow rate of about 8000 gallons per <br />minute (gpm) and a long term steady rate of about 500 gpm. <br />On the north side of Jumbo Mountain colluvium from an ancient <br />landslide that removed the minable portion of the B Seam lies directly <br />atop the lower portions of the B Seam. Water could be expected to <br />infiltrate through the colluvium and migrate from bedrock units into the <br />colluvium, emerging as springs or seeps down-dip of the proposed <br />mining <br />37 <br />