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.~ - <br />NPDES <br />Discharge monitoring reports for 1992 and 1993 show that several ponds have had discharges that <br />have exceeded State water quality standards for total suspended solids and iron. In 1992, of the <br />seven ponds serving the mine area, (A through G) three had exceeded NPDES standards at least <br />once. In 1993 Ponds C and D experienced discharges that exceeded NPDES discharge limits. All <br />ponds are designed to conform to Rule 4.05.6(3) to contain the runoff from a ] 0 year 24 hour event. <br />The Discharges have occurred within 24 hours of precipitation events and may be eligible for <br />exemption for these parameters. These ponds only receive water as a result of precipitation events. <br />The mine has been working with the Colorado Department of Health, Water Quality Control <br />Division to resolve this problem. <br />Recommendations <br />From my review of the 1992 AHR I recommend that the Kerr Coal Company make the following <br />changes to their monitoring plan. <br />Check all well depths, casing condition, annulus condition annually and make sure all wells are <br />capped. This information should be submitted in the annual hydrologic report. If repair or <br />rehabilitation is necessary the mine should perform this as needed. <br />Field instruments should be calibrated on a regular basis. <br />Electrical conductivity should be adjusted to 25 degrees C. and given as specific conductance. <br />Key water quality parameters such as water level, specific conductance and TDS should be <br />presented graphically in the AHR. <br />RPP/rpp/marahr92. sam <br />