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•/ <br /> \/ <br /> cotter <br /> Via FedEx <br /> May 4, 2016 <br /> Michael Cunningham <br /> Division of Reclamation and Mine Safety <br /> Department of Natural Resources <br /> 1313 Sherman Street, Room 215 <br /> Denver, CO 80203 <br /> Subject: Technical Revision 23 ("TR-23"); Deposition of Excavated Solid Source Term <br /> Material ("Waste Rock")onto Existing Waste Rock Piles("WRP"), Schwartzwalder Mine, <br /> Golden, Colorado, Mine Permit 1977-300. <br /> Dear Mr. Cunningham: <br /> Please find enclosed the rationale,technical basis and plans requesting TR-23 and a check for <br /> the amount of$1,006 to cover the Technical Revision fee. <br /> As you know,the reclamation plan submitted as part of Amendment 4 discusses the removal <br /> of Waste Rock from the Schwartzwalder valley floor and subsequent transfer to a permanent <br /> disposal location in an existing mine void,the"CV Glory Hole". TR-23 is being submitted to <br /> request approval to place this same Waste Rock onto and within the currently permitted <br /> capacity and boundaries of the existing WRP instead of deposition in the CV Glory Hole. <br /> Deposition onto the existing WRPs is preferred to avoid significant safety and environmental <br /> concerns related to the risks of transporting hundreds of truckloads, over a period of at least <br /> three construction seasons, of Waste Rock up the dangerous mine road for disposal in the CV <br /> Glory Hole. Cotter still intends to dispose of some materials(construction debris, <br /> miscellaneous piping etc.) in the CV Glory Hole that are inappropriate for deposition onto <br /> the WRPs. However,this volume of material is likely an order of magnitude less than that of <br /> the Waste Rock. <br /> In 1983,the Schwartzwalder Mine Permit 1977-300 was amended to expand the two existing <br /> WRPs to support mine operations in future years. This amendment included the detailed <br /> design of the engineered expansion and the required environmental justifications, which have <br /> been included as enclosures to this request letter. To date, approximately two thirds of the <br /> approved 603,000 yd3 expansion has been utilized, leaving space for 205,000 yd3 of available <br /> storage of Waste Rock from the mine site. The volume of the Waste Rock to be excavated <br /> and taken to permanent storage on the WRPs is estimated to be 32,000 yd3 to 54,000 yd3, far <br /> below the permitted capacity of the WRPs. <br /> In TR-23, Cotter proposes to deposit the excavated Waste Rock in the unused yet permitted <br /> storage locations, specifically on top of the existing North and South WRPs,well above the <br /> Cotter Corporation Telephone(720)554 6200 <br /> 7800 E.Dorado Place,Suite 210,Greenwood Village,CO 80111 Fax(720)554-6201 <br />