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COLORADO DEPARTMENT OF HEnLTH, Water Quality Control Division <br />Rationale'- Page 12, Penttit No. CO-0043648 <br />!V. FAC/LITYDESCRIPT/ON <br />A. lndttstry Description <br />1. Type of lndttstry - TTtis facility is a cyanide heap Ienclt gold mining operation. The project consists of the <br />Cresson Mine Pit, [ire Valley Leach Facility, the Mi»erals Benefacliort Facility. the crusher and waste rock and <br />overburden stockpile areas. The ore production rate is planned to 6e 8 million tons per year, wit/t a projected <br />mitre excavation period of seven years. The leaching facility tivi[! 6e operated jot approximately nine years. <br />Reclamation of tl:e mine site will include backfil[ing mine pit areas, detoxijica[ion of the cyanide leach heap, <br />brenciting t/te leacft pad linei sys(en:, and revegetntion of disturbed areas. <br />2. Potential Sources ojPolluranrs - The sources of t/te pollutants that may 6e discharged include cyanide or metals <br />that may be seeping through existing mine tailings or Wray be released after the movement of the railings, spills <br />or leaks of ryanide leaching solution from t/te new leach /reap, or metals released front rock that will be exposed <br />to rite environment as a result of [he mining nctiviry. <br />3. Chemicals Used -Other than the pollutants discussed above, no other citenticals wJtich may be stored nt the <br />mine site are likely to be present in quantities or used in a manner which would pose a risk of being discharged <br />to waters ojtlte State. <br />B. Wastetvnter Treatment Description: The mining company has not yet completed rite design of treatment systems. /n <br />general, it is expected that pH adjttstntent, cyanide removal, and settling treatment systems will be needed. <br />V. PERFORMANCE HISTORY -Reserved <br />VI. TERMS AND CONDIT/ONS OF PERMIT <br />A. Determination of Effluent Limitations <br />1. Effluent Limitations -The following limits wifl npply and are discussed in Sections V/.-A.2. and VI.-A.3. <br />a. "No Disclarge"Limitation for the Valley Leach FacilitX <br />Except as allowed under the exemptions described in the sections below, there shall be no discharge <br />from fire Valley Leach Faclliry, pursuant to federal effluent regulations at 40 CFR, Part 440.104. Thls <br />limitation does not npply to any discharge from the various conduits that comprise t/te Leach Facility <br />underdrain.. <br />b. Annual Precipitation Exem~on From "No Discharge"Limitation - Discha~e Point OOSB <br />Pursuant to 40 CFR, Parr 440.104, in the event that the annual precipitation (measured as a 365-day <br />moving average) falling on the Valley Leach Facility and the drainage area contributing surface runoff <br />to the leaching facility exceeds the annual evaporation (also measured as a 365-day moving average), a <br />volume of water equal to the difference between annual precipitation falling on the facility and the <br />drainage area contributing surface runoff to the facility and the 365-day moving average evaporation <br />may be discharged subject to fire limitations set forth in Table I.A-1 for point OOSB. Verbal notiflca[ion <br />shall be given within 24 hours, and written notification shall be submitted to the Division within 5 days <br />of any discharge from rite Va[[ey Leach Facility that would qualify for this exemption. <br />c. Storm Exemption From Federal E„(fiuent Limitations -Discharge Point 005E <br />Pursuant to 40 CFR, Part 440.731, if, as a result of precipitation, point the Valley Leac/t Facility has a <br />discharge which violates limitations oj40 CFR Part 440 (New Source Performance Standards) or water <br />quality standard based limits, the discharge may qualify for an exemption from such limitations if the <br />fo!!o}ving conditions are met: <br />