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<br />July and August, the ventilation air is warmed as it passes through the mine. This increases its <br />moisture carrying capaaty and the air picks up considerable quantities of moisture wherever there <br />' is water available. During the summer months the air is actually cooled, however, the difference <br />in relative humidity still allows the exhaust air to carry away more moisture than is brought in with <br />' the intake air. <br />Some of the water entering the mine is collected in sumps at various locations. In the past, this <br />' water was eventually pumped out of the mine through the East Intake or to process pond two <br />(PP2). Then all water discharged from the mine was discharged at the sump dewatering holes <br />' shown on Plate 1. During this year approximately 68% of the total was discharged from SDH-2 <br />(1,123,340 gallons), and none from SDH-3 and 32% from SDH-5 (520,950 gallons). This water <br />is further discussed in the next section. <br />1 No underground water is being pumped out since the fire episode. For the remaining life of the <br />D-Seam mine (about four years), the underground water will be left to fill the mined out areas. <br />' 2.2.2.6 NPDES Discharges and Whole Effluent Testing At present, Western Fuels-Utah has <br />15 NPDES outfalls. Only six ouffalls experienced a discharge during this monitoring period. The <br />vast majority of water was discharged from the ouffalls for the mine dewatering boreholes (SDH-2 <br />and SDH-5). The water from SDH-2 was discharged at outfall 024 and the water from SDH-5 <br />was discharged at ouffall 026. There was no discharge from SDH-1 or SDH-3. None of these <br />outfalls are discharging since the January 31, 1996 underground fire episode. The NPDES <br />discharge quality parameters for the water year aze summarized in Table 2-4. <br />Western Fuels-Utah started the whole effluent toxicity (WET) testing program beginning in the <br />' fourth quarter of 1989. The mine water effluent was found to be toxic to the test species. <br />Accelerated testing was conducted but the toxicity to the species continued. <br />In a meeting with Colorado Water Quality Control Division (WQCD) staff on January 31, 1992, the <br />WFU staff reiterated the biomonitoring events, and various measures taken to identify the toxicants <br />and to reduce the toxicity. WFU took the following steps to identify potential toxicants. <br />' • In the early stages of WET testing, the associated HZS in the effluent was deemed <br />to be a potential toxicant. However, a WET testing done by ENSR Consulting in <br />June 1990 after removing H2S by aeration still showed toxicity. This result <br />' indicated that some other factor(s) also contributed to the toxicity. <br />1 <br />' 13 <br />IJ <br />