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Y.{ <br />iii iiiiiiiiniuiii <br />999 <br />CYPROS BMPIRB <br />~ CONDONATION <br />A Cyprus Amax Company <br />P.O. Box 68 <br />Craig, Colorado 81626 <br />(970) 824-8246 <br />December 8, 1998 <br />Mr. Byron Walker <br />Environmental Protection Specialist <br />Colorado Division Of Minerals and Geology <br />1313 Sherman Street, Room 2l5 <br />Denver, Colorado 80203 <br />RE: Ei;C`.E MINE, PE^."4:T NO..^.-.°,1-13y <br />1997 Annual Hydrologic Report, Adequacy Review <br />Dear Mr. Walker: <br />RECEIVEC <br />FEB 2 4 1999 <br />Division of Minerals 8 Geobyy <br />In response to your request for further explanation of the information provided in Fi~ntres IG and 17 of Ute <br />1997 Annual Hydrologic Report, I submit Ute following: <br />Figure 1G <br />Figure lG of the 1997 AHR (as well as previous AHRs) charts Ute water discharged from We No. 5 and No. <br />G runes, expressed as a constwtt rate of flow for Ute reporting period of one year (tire mean annual <br />discharge mte). Historically Utese sources were pwnped nearly continuously in order to maintain constant <br />water levels at Ute undergrowtd reservoirs that each served. Under Utose conditions, Ute combined flow of <br />Ute two sources also served as a measurement of inflows into the mine. <br />During 1997, wiW Ute mine in temporary cessation, these pumps were run only. intermittently (typically one <br />week per monUt or less). As you can see, the water discharged during Utese intermitt_nt pwnping periods, <br />particularly when projected as an equivalent constant flow (the mean annual dischlrge mte), is raUter <br />insignificarri (less than 0.5 gal/min) when compared prior years. FurUter, Utere is no longer a correlation <br />between Ute discharges and n»ne inflows. <br />Figtue 17 <br />Historically, discharges Cront tttittes No. 5 mtd No.G were measured at Uteir respective N.P.D.E.S. discharge <br />points weekly. Since pumping was continuous (as explained above), tlows at the discharge points were <br />also continuous and nearly equivalent to the (low mctcred at the pwnps. In prior years, the weekly ^ow <br />roles, at the N.P.D.E.S. sites, were grapltcd as Figuue 17. <br />However in 1997, during temporary cessation, Utese pwnps were run only intenniltently. The water Utat <br />was puwped to the surface, and then tluough a series of ditches and Ireaunent ponds, did not always <br />produce a discharge at the N.P. D.E.S. sites. Weekly readings, therefor, did not provide mewtingful data for <br />the 1997 AHR. ht lieu of the custoutnry N.P.D.E.S. discharge data, in the 1997 AHR Figttrc 17 provides a <br />monlldy listing oC the mctcred quantities of +vatcr pwnpcd out of the mines. <br />