HYDRO31281 - Laserfiche WebLink

Home Browse Search

,. COLORADO DL• PARTMF_M' OF HEALTH, Wnrer Quality Control Division Rruinrmle - Pnl;c 4, Pcrmit Nn. CO-0032638 B. Receiving Waler Data uali - No quality data jor tither Oak Creek or unnamed tributaries to Trout Creek were available. Therefore, for purposes of calculating inter quality-basr~ effluent limitations, background concentrations of parameters of concern will be assumed to be zero. 2. Quantity. Acute and Chronic Low Flows -Although, the flows used to calculate acute and chronic ef/luenr limitations are the one day in three year low flow (lE3J and the 30 day in three year low flow (30E3) respectively, these flows were not available for the receiving streams. 7hcrcfore, as done in the previous permit, the 7~ay, 10-year low flow (lQ10) jor unnamed tribwtries to Trout Creek will be used to calculate ejjhtent Urnitations. The previous rationale assumed the 7Q10 to be 6.0 cjs. Law flow data Kns not avallable for Ohk Qrcek, the receiving stream of Ou[faU 001. /n adduion, the Colorado Mined Land Reclamation Division and the State Engineers Offtce require ponds to be dewatcred within 36 to n bows afltr a pracipitation event. As discussed in the previous permit rationale, the division believes that disdwrges will ocrra• when the lbw of Oak C3-eek is above the 7Q10 low flow. As a result, no kater gtutGry~ased t,Qlutnt limitationr, with the exception of pH, wU! be calculated for OutfaU 001. /V, FACILITY DESCRIPTION A. Industry Description The Pittsburg and Midway Coal Mining Company's Edna Mine rs a swface oval mine. Coal is stripped, drilled, blasted, and hauled to the tipple area. In the tipple area, the oval is crushed and screened before it is shipped out. According W a lnspetxion report, tavndutxed by the Cobrado Deparvnuu of Health on September I6, 1991, and inforrmtion submitted by the Pnmittee in the ptsmit renewal appUcatian, the estimated remaining life of the faciGry is 10 to 12 years. On August 17, 1987, rbe perntirtee requested that the winter monitoring exemption for OutfaU 003 be atended ro Outfall 006. Amendmem Nl to the previous permit extended the winter monitoring exemption to OutfaU 006. David Btverlin, resident engineer of the Edna Mine, on July 6, 1993 provided the following information on the permitted discharges from the Edno Mine: • OutfaU 001 contains surface runofffrom the apple area • Outjall 002 aontaires surface runofffrom a racltdrrted area of the site • OutfaU 003 contains surface rwwfffrom a reclaimed area of the site • Outfall 0104 contains surface runofffrom bath active and reclaimed areas of the site • Outfall 005, a panutted ourfall not curremly in existence, wUl contain storm inter runofffrom the facUiry grounds • OutfaU 006 contains groundwater spring discharges from a recbimed area of the site Additional descriptions of the facility are comained in the previous permit rationale. 1. Tvoc oflndustrv - Pituburg and Midway Coal mining Company operates a surface coo! mine. 2. Sources to the Treatment Plant - No changes in the sources to the treatment systems have occurred since the issuance of the previous permit.