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Outaoina Water As coal is mined, water is added by dust control sprays on the continuous miners, the longwall shearer and at transfer points along the conveyor belt system. This water is then carried out of the mine as surface moisture on the raw coal. This added coal ' surface moisture represents a 4% increase in the raw coal moisture content. The raw coal tonnage produced during this reporting period was 2,630,433 tons. ' Water leaving the mine as ventilation humidity represents a large quantity in the water balance. The temperature of the exhaust ventilation air is almost constant, at 60° F. ' No underground water has been pumped out since the fire episode. Water encountered in the active areas of the mine is pumped to the mined out D seam area for storage. Currently ' only about 8 gpm is pumped on average. 2.2.1.6 NPDES Discharges AY present, BME has 15 NPDES ouffalls. Only one outfall (DP1) experienced discharge during this monitoring period. Ouffalls 024 and 026 at the sump dewatering holes have not discharged since the January 31, 1996 underground fire episode. All discharges were within the permit requirement. 2.2.1.7 Whole Effluent Toxicity (WET) Testing No WET testing was conducted during the ' water year since there was no discharge of the underground water from the sump dewatering holes or from outfall 004 (Pond PP2). A history of WET testing at Deserado Mine follows below: BME started the whole effluent toxicity (WET) testing program beginning in the fourth quarter of 1989. The mine water effluent was found to be toxic to the test species. Accelerated toxicit to the s ecies continued te tin wa co ducted but th y . g p s s n e i~ II In a meeting with Colorado Water Quality Control Division (WOCD) staff on January 31, 1992, the BME staff reiterated the biomonitoring events, and various measures taken to identify the toxicants and to reduce the toxicity. BME took the following steps to identify potential toxicants. • In the early stages of WET testing, the associated HZS in the effluent was deemed to be a potential toxicant. However, a WET testing done by ENSR Consulting in June 1990 after removing HzS by aeration still showed toxicity. This result indicated that some other factor(s) also contributed to the toxicity. • In September, 1990, ENSR Consulting was directed to conduct a "toxicity characterization" study to identify the primary cause of the toxicity. This study considered pH effects, volatile organic carbon, metals chelation, aeration, total 9