2008-04-15_REVISION - M1980244 (351)

Home Browse Search

• 13.5 Designated Chemical(s) Evaluation The MLE will not change the types of designated chemicals or expected concentrations used in ore beneficiation at the Cresson Project. The designated chemicals include sodium cyanide and cyanide solutions, sodium hydroxide, and hydrochloric acid. Table 13-2 shows the expected quantities in storage and in solution for the designated chemicals, expected concentrations for the dilute cyanide solutions used in leaching, and the fate of the designated chemicals. Material Safety Data Sheets for designated chemicals are included in Appendix 12, Volume VII of this document. 1.3.6 Designated Chemical(s) and Material(s) Handling The use, disposal, and detoxification of designated chemicals for ore beneficiation are described in Sections 6.0 and 11.0 of the Project Description. CC&V has documented the containment of all designated chemicals in the Spill Prevention, Control and Countermeasure (SPCC) Plan which is included as Appendix 12, Volume VII. All designated chemicals have a minimum of primary storage and secondary containment to prevent materials from entering stream channels, escaping into areas subject to storm • water runoff, or migrating offsite. The concrete containment for the ADR is graded to drain to the VLF. Below the concrete containment is a synthetic liner which is also placed to drain to the VLF. The MLE proposes an extension of the existing VLF (i.e., Phase 5), which will be keyed into the existing VLF using the same design and construction as previously approved by the MLRB for the Cresson Project. These engineered features are buttressed by good housekeeping protocols, preventative maintenance of best management practices to prevent spills, safe handling and material transfer practices and regular visual inspections of containment structures. Closure of the VLF, including Phase 5 associated with the MLE, will require rinsing of the ore with recirculated solution from the VLF, followed by hydrogen peroxide-assisted removal of the cyanide, per the discussions in Section 11. Closure will occur over an approximate four-to five-year period. As a result of recirculation and rinsing associated process equipment will be rinsed and rendered suitable for demolition and salvage. The MLRB has approved a standard of an average concentration of CNWAD less than 0.2 mg/L in the rinsate or in results from meteoric water mobility testing of the spent ore. Once data supporting this standard has been collected, CC&V will provide this information to the OMLR for concurrence. Following concurrence, CC&V will move forward with VLF reclamation. • Cripple Creek & Victor Gold Mining Company Cresson Project Mine Life Extension 13-6