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Mr. Boulay Page 2 <br />1995 AHR Responses <br />6. Both SG-1, and its replacement, GB-1, were installed in alluvium materials to monitor for <br />potential impacts from the refuse pile. Hrstorically, water levels in SG-1 ranged from <br />elevations of 6145 to 6185, stabiliring in later year to a range between 6150 and 6170. GB-1 <br />was placed to include this stabilized range. To detect impacts at shallower depths, GB-1 was <br />slotted from 10 feet down (i.e. is screened between 6148 and 6188). The water quality of <br />samples at the greater depths of SG-1 likely represent alluvial water quality prior to placement <br />of the refuse pile, and aze considered a valid baseline. <br />Please find a revised page 11 enclosed. Historic inflows have been very small, typically of a <br />`weepy" nature, and quantities have been estimated, based on observations and deductions <br />from other known values of the hydrologic balance (pumped inflow, pumped discharge, etc.). <br />As stated in the text, inflows were typically of short duration and any relatively high flows <br />diminished rapidly. <br />8. Please find a corrected Table 1.6-1 enclosed. <br />9. A sump was developed in the northeast comer of the 1-5 NW longwall panels to accumulate <br />water that was generated from the development and secondary mining of the westem portion <br />of the West Elk Mme. This sump is located in the lowest, down-dip portion of the western <br />segment of the northwest panels of the mine. Any inflows or face runoff flows naturally to this <br />point. Water may also be pumped to the sealed area to be gathered in this sump as well. The <br />seals in the 1st Northwest Tailgate were constnrcted between cross-cuts 14 and 15, about mid- <br />way from the B West Mains to the northeast comer of the sump. These seals were constructed <br />so that water could be pumped into or from this sealed sump area. This sump is an integral <br />part of the West Elk Mine's operational water management system. Water that is discharged <br />from this sump will be measured by flow meters that have been installed on the pipeline to the <br />surface, where the water is treated to reduce total suspended solids, if necessary, to CDPS <br />standazds and is fatally discharged. Please fmd a revised page 12 that recognizes the sump as <br />an operational element of the discharge system and the addition of a discharge flow measuring <br />capability. <br />10. Please fmd a revised page 12 and page 14 (Table 1.7-1) enclosed. After encountering the large <br />inflow earlier this year (1996), MCC has collected and analyzed random samples from this <br />inflow. <br />11. Please find a revised Table I-1 enclosed. Notations have been added to clarify entries. <br />Maximum and average values for TSS under outfall 007 have been corrected. Discharge 007 <br />NPDES parameters for 5-Day BOD, Total Suspended Solids (TSS), and Fecal Coliform are <br />30~ay average and maximum 7 day average, with a prescribed frequency of analysis of one <br />per month, for a three month period. Thus the 30-day average becomes the average of three <br />analyses, and the maximum becomes the highest of the three for the reporting period. <br />12. Please fmd a revised Page 14 enclosed. Table 1.5-1 should have read Table 1.7-1. <br />