2002-05-13_PERMIT FILE - C1981018

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CO.%?_4D~~ DEPART?i=::: Ui HEPI,TH • :rate: ~uaiity Gon[roi Division P.ationa.e - Page 6 ~~r~-ic :;o.: ce-oo35~2s Gutfalls 001, 002 and 003 This permit amendment will also revise the efflue7lt limitations for oucfalls 001, 002 and 003 through the incorporation of Federal BAT for Coal Mines which was recently adopted by EPA. The changes dictated by EPA are described below. The numerical limitations currently in effect will remain as shown in the current oermit, with the exception of pH. The pH limitations are changed from 6.0 - 9.0 to 6,5 - 9.0. This is in accordance with the water quality standards, no[ BAT, but is changed as part of the amendment. Storm exemption requirements will also change. Whereas in the past, 10-year, 24-hour containment was required, under BAT it is not, The permittee may build ar.y type treatment facilities he chooses. Effluent limitations are based solely on whether precipitation has occured and if so, the volume of precipitation that occurred. During storm events less than the facility's 10-year, 24-hour event (or enui~:aient snowmelt) the permittee may meet alternate limitations shown below in Table 3. • Table 3 Parameter Limitation Flow (MGD) Monitor Oil and Grease (mg/1) 10.0 Settleable Solids (ml/1) 0.5 Salinity Pioni[or The per-ai[tee may meet a third set of limitations for discharges caused by precipitation greater than [he 10-year, 24-hour event (or equivalent sno,nelt). These limitations are shown in Table 4. Table 4 Parameter Limitation Flow (MCD) Monitor Oil and Grease (ml/1) 10.0 Salinity Monitor In order for the permittee to claim either storm exception, documenta[Son . proving an applicable event occurred must accompany the discharge monitoring report (D:7R). In the absence of docum~nta[ion, the Division will determine compliance based on the dry-•.+eather limitations.