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Mr. Mathews <br />July 12, 1995 <br />Page 2 <br />The Mine Foreman was sent to do a initial <br />that the immediate problem was the result <br />with Pump A being overfilled. The excess <br />the roadway picking up solids on its path <br />pump more which caused the portal sump to <br />you may remember this portal sump was brig <br />it and it apparently had been overflowing <br />our observation. <br />investigation and found <br />of the sump associated <br />water was running down <br />to Pump B which had to <br />overflow more, etc. As <br />n full when we looked at <br />immediately prior to <br />The Mine Foreman stopped the overfilling problem immediately by <br />turning off Pump C and turning off the drain line from the sealed <br />area (location 8), but pumping at Pumps A and B had to continue, <br />including dirty water in the system and in route to Pump B, to <br />keep up with inflows at the portal underdrains (Location 1). The <br />water had cleared up by the next morning. An estimated 30,000 to <br />50,000 gallons of higher than permitted TDS water was discharged <br />that day. Further investigation revealed that the overfilling <br />was due to a partial blockage in the impeller of Pump A which <br />prevented it from keeping up with inflows from location 1 and <br />discharge from Pump B. Normal discharge from this pump is 230 to <br />250 GPM but at the time it had dropped to 190 GPM. <br />Repair work on the impeller of Pump A has reduced the possibility <br />of a reoccurrence of over filling the portal sump. Another <br />change that will be made in the near future will be to pipe water <br />from the sealed area (location 8) to the sump at Pump C. The <br />schedule for dewatering the seals has caused close calls at the <br />portal sump in the past. The current schedule is to alternate <br />between draining the seals for several days and letting the water <br />built up for several days. By spreading out the seal discharge <br />the load on Pumps A and B are spread out and better mixing <br />occurs. <br />Please let me know if you have any further questions. <br />Sincerely, <br />Larr~ M. Reschke <br />Eng eer <br />LMR:lmr <br />cc: Colorado Department of Health, WQCD <br />U. S. Environmental Protection Agency <br />Dick Reisinger(WACC) <br />MATH712 <br />