Laserfiche WebLink
zoos <br />Historic Allen Mine waste materials appear to be the major contributors to saline alluvial ground <br />water quality in the vicinity of the New Elk Mine (PAW-3 and PAW-4) (Figure 3.2-3). Saline <br />conditions were anticipated in the PHC, and conductivities and TDS concentrations have been far <br />lower than expected. During March and April of 1985, 500 feet of the Middle Fork ofthe Purgatoire <br />River was diverted to the north to create additional room for the coal stockpile at the New Elk <br />Preparation Plant. The original channel was backfilled with mine waste, and two alluvial wells, <br />PAW-3 and PAW-4, were established to monitor water elevation and chemical parameters. Water <br />quality does not appear to deteriorate significantly due to the presence of refuse in the backfill <br />between PAW-3 and PAW-4 and measures of salinity, sodium, and sulfate are far lower than <br />predicted by the PHC. A threefold increase over historic values in iron quantities in PAW-3 and <br />PAW-4, maybe due to the steel casing of the wells. No further monitoring is required for PAW-3 <br />and PAW-4. Data on PAW-8 (Table A-11) and the Stiff Diagram indicate that seepage from the <br />current refuse disposal area contains similar concentrations of sodium, potassium and calcium to the <br />pre-law mine waste (PAW-4). Leaching may be a cause for lower values from the old materials. <br />Data from PAW-9 downstream of the New Elk facilities indicated dilution having an effect on <br />concentrations. <br />3.2.4 New Elk Mine Water <br />During the third quarter of 1989, the New Elk Mine was sealed and access to the mine workings <br />terminated. Mine inflows are flooding the abandoned mine workings. Previous studies and reports <br />suggested an inflow of 177 gallons per minute (gpm) and calculated inflows ranged from 142 to 468 <br />gpm based on measurements taken at Station NEW-4. A number of approximations were made in <br />the calculation of rates of inflow. From mine maps, the dip of the mine floor was determined to be S <br />percent, and the water line crosses approximately 12,000 linear feet of mined areas. The available <br />volume is based on an average extraction of 60 percent. The calculations assume that the entire <br />mined area below the water level measured in NEW-4 is flooded (i.e., no trapped air pockets). <br />Figure 3.2-4 Groundwater Recovery, portrays a rise of groundwater in (flooding of) the sealed <br />New Elk Mine. The rise maybe due to reduced surface area of the mine to be filled (i.e. filling faster <br />with the same infiltration rate). Continued monitoring will provide the information to clarify the <br />phenomena, and permit a more accurate projection of hydrologic consequences. <br />Inflow water quality information is being obtained at the sealed New Elk Mine (see NEW-2, Table <br />A-14, NEWS, Table 16 and NEW-4, Table A-18). Stiff diagrams of mine water quality are <br />provided in Figure 3.2.5. This water is of relatively high conductivity, and high concentrations of <br />total dissolved solids, bicarbonate, and sodium. None of this water has been discharged from the <br />sealed mine to date. <br />62fi-Annual Hydrolic Monitoring (Apr9.02).doc 23 <br />April 17, 2002 <br />