Laserfiche WebLink
1 <br />' kerr coal company <br />oo. gar wade n, coio•.OO a0d80 ~ ~YJ31 77J+r11 <br />Date• s/9/f3 <br />' Ms. Patricia A. Nelson <br />Colorado Department of Health <br />Water Quality Control Division <br />' 4210 Eut 11th Avenue <br />Denver, Colorado 80220 <br />' Re: Rerr Coil Company -Mur Mine (Permit No. COG850021), Request for Stormwater <br />Exemption <br />' Dear Ms. Nelson: <br />Rerr Coal Company (Kerr) owns and previously operated the Mur Mine, located approximately <br />' fourteen miles eut of the town of Walden, Colorado. Mining operations at the mine have <br />ceased and the mine is currently in an attive reclamation mode. Drainage and sediment control <br />for the mining related disturbance is provided by a number of engineered sedimentation ponds, <br />' collection/diversion di[ches, and associated drainage structures. Dischuge from the <br />sedimentation ponds is controlled and regulated under appliable provisions of Permit COG <br />850021. Discharge for the [w~elce individual outfills under this permit comes almost exclusively <br />' from snowmelt runoff, with no process v.•a[er discharge and discharge from rainstorms being <br />rue. <br />All sedimentation ponds ue designed and maintained to provide a minimum detention time of <br />' at lent 24 hours for retained runoff resulting from the 10 year, 24 hour storm event. While the <br />ponds are designed to provide adequate detention time to illow settlement of suspended solids, <br />due to the characteristia of the dominant soil types in this uea both undisturbed and disturbed <br />' area runoff typially have relatively high levels of suspended solids. Tn addition, a relatively high <br />percentage of the suspended solids in the runoff ue fine colloidal materials which do not radily <br />settle out of suspension. <br />1 <br />1 <br /> <br />1 <br /> <br />During periods of high flow due to either snowmelt or rilnfill runoff, the noted factors <br />combine to limit the trapping efficiency of the existing sedimentation ponds with the result that <br />concentrations of certain puameters in pond discharge may exceed appliable effluent <br />limitations. The accompanying monitoring report(s) indiate ezceedance of effluent limitations <br />for the following discharge point(s), effluent parameter(s), and monitoring period(s) for which <br />an exemption is requested. <br />Dischar eg Point <br />.~a.~ <br />Parameter( Exceeding Limitation <br />%SS /fa <br />Discharge Ratefdsl Date s <br />asz ~, <br />Giv y,~ yj <br />,goy <br /> <br />