Laserfiche WebLink
ENSR Consulting in June 1990 after removing HzS by aeration still <br />showed toxicity. This result indicated that some other factor(s) also <br />contributed to the toxicity. <br />• 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 LC50 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, <br />1997 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 />~~ <br />