2011-08-08_REVISION - M1977493 (33)

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• • Technical Revision (TR -18) Climax Molybdenum Company Environmental Protection Plan Permit No. M- 1977 -493 T - 3.4 Alateria /Safety Data Sheets for Designated Chemica /s Current Material Safety Data Sheets (MSDS) are attached in Appendix T -B. Updated MSDSs are maintained at the site. These data sheets list permissible exposure limits, monitoring and measurement procedures, health hazard information and exposure effects, recommended medical procedures for human exposure, emergency first aid procedures, personal protection, leak and spill procedures, and waste disposal methods. T - 3.5 Disposa /, Decommissioning, Detoxification or Stab //izat /on Procedures for the disposal, decommissioning, detoxification or stabilization of designated chemicals during temporary cessation or final closure are discussed in the following sections. T - 3.5.1 Temporary Cessation /Prolonged Lack of Mineral Production Under the scenario of formal temporary cessation or periods of prolonged lack of mineral extraction and production, designated chemicals at Climax would be used or removed from the site. Mixed chemicals such as Nokes Reagent and NaCN in solution would be used in the milling process until depletion of the supplies. The distributor would be contacted to assume possession of unmixed and uncontaminated chemicals, and the material would be transported off -site in the same manner that it was received at the site. Those designated chemicals used in the water treatment system at Climax would remain at the site and would continue to be used. Water treatment and discharge would not cease under these scenarios. If unmixed chemicals were contaminated or the distributors were to decline possession, then detoxification or stabilization and disposal would be managed pursuant to solid and hazardous waste regulations. T - 3.5.2 Final Closure Upon final closure at the conclusion of operations at Climax, designated chemicals will be handled in similar fashion as under the scenario described above. The exception is that lime, sulfuric acid, and flocculant used in the water treatment process will remain at the site until no longer required in the water treatment process. Removal and disposal of water treatment chemicals will occur as discussed for mill process chemicals during periods of temporary cessation or prolonged lack of mineral production. T -4 Acid - Forming Materials and Acid Mine Drainage The Climax ore body beneath Bartlett Mountain contains unoxidized sulfides that, in the presence of oxygen, water, and bacteria, have the potential to become an acid - forming material as defined in Rule 1, Section 1.1(1). Likewise, waste rock materials deposited in McNulty OSF, North 40 OSF, and tailing material deposited in the TSFs also contain material with acid - forming potential. Climax concurred with this fact in its response to the DRMS (August 31, 1994) when it accepted the DRMS determination that Climax was a DMO under the amended rules. In addition, water that percolates through the open pit area and accumulates in the pit or closed underground workings contacts sulfide bearing material and, in turn, has the potential to become acidified, thus, meeting the definition of "Acid Mine Drainage" in Rule 1, Section 1.1(2). Overburden material will be handled during operations, to the extent practicable, to minimize the generation and impact of acid drainage as well as the volume of water requiring treatment during and after mining. As overburden material is placed as part of ongoing operations, Climax will continually look for and identify opportunities to manage overburden materials to minimize acid rock drainage and the volume of water requiring treatment. Techniques will include, but may not be limited to, material segregation (based on acid generating potential), upgradient diversion of unimpacted water, and Climax's election to implement concurrent reclamation to minimize future acid drainage and the quantity of water requiring treatment. Concurrent reclamation of OSFs is described in Exhibit E. As required under Rule 6.4.21(6), appropriate EPFs have been identified to minimize, capture and treat acid mine drainage (see Section T -5.3), The locations of OSFs have been developed with consideration of existing conditions as well as overall EPP: Revision R1 T -11 July 2011