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' In September, 1990, ENSR Consulting was directed to conduct a "toxicity <br />characterization" study to identify the primary cause of the toxicity. This <br />study considered pH effects, volatile organic carbon, metals chelation, <br />aeration, total dissolved solids (TDS) and ammonia. The lab determined <br />high TDS (chlorides) as the primary cause of the toxicity. However, a <br />' recent review shows no correlation between LCD values and chloride or <br />TDS levels. <br />' BME took the following measures to reduce toxicity of the effluent. <br />' On-site aeration structures were installed for HzS removal before <br />discharging the effluent. <br />' A pilot test was conducted to identify a flocculent for removing high levels <br />of oil and grease from the effluent. <br />• The main water source of the mine was changed from the high TDS(>5000 <br />ppm) alluvial well water to a significantly lower TDS (500 ppm) surface <br />lagoon. <br />' The raw water tank was thoroughly cleaned and disinfected to remove <br />sludge built up over years. This sludge was found to contain significantly <br />high levels (1000 colonies/ml) of bacteria. <br />• An MSHA waiver was received to stop the use of Wendon Dustrol-10 <br />surfactant in the water spray at the longwall face. The surfactant has been <br />found to be lethal to fish life at 500 ppm. <br />The WQCD also sent an effluent sample and prior toxicity reports to the EPA laboratory in <br />Duluth, Minnesota to investigate the cause of toxicity. WQCD never heard from EPA in <br />this regard. WQCD does not think it is now necessary since the mine has been passing <br />the WET testing during the three (1994-97) water years. Besides no mine water is <br />discharged at this time requiring WET testing. A copy of the letter dated January 30, 1997 <br />from WQCD is attached in Appendix H of the Thirteenth Annual Hydrology Report. <br />On December 28, 1992, WQCD wrote to WFU (now BME) asking either (i) to develop a <br />control program which eliminates the toxicity through treatment of the TDS or (ii) to <br />perform a study which determines if TDS is having a toxic effect on the stream and to <br />develop a level of TDS at the discharge point at which an instream impact is not expected. <br />10 <br />