2013-06-24_REVISION - M1990057 - Laserfiche WebLink

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Letter to Nick Michael 3 June 24, 2013 AM -01 Application Adequacy Review File No. M- 1990 -057 demonstrating the capacity of the ditches and impoundment structures to contain operation solutions and the volume of water generated by a 100 year 24 -hour rainfall event. Since the Leadville Mill has been classified as a Designated Mining Operation (DMO), stormwater runoff will not be allowed to report to the TSF. Stormwater must be routed around the mill facility or otherwise controlled through the use of BMP's. 13. Please provide the tank capacities and operating solution volumes for the mill operation as required by 6.3.3(2)(a). The Division must confirm that the secondary and tertiary containment systems are adequate to contain 120% of the volume of the total solution in the mill facility. 14. The Applicant has stated a portable generator will be available on site for emergency conditions. Please describe how the generator will be utilized in an emergency situation. Will the generator have to be manually turned on, or will it be setup to automatically turn on when electrical service is interrupted? Also, demonstrate that the portable generator has sufficient wattage to run the pumps and to circulate fluids through the various circuits of the mill. 15. As part of the approval of Technical Revision No. 3, the Applicant stated that the tails would be maintained in an alkaline state and would enter the TSF with a pH of 8.0 to 9.0. The current milling plan does not contain a discussion of the target pH for the tails which report to the TSF. Please include a discussion of how the pH of the tails will be managed prior to discharge into the TSF and specify how and at what point the pH will be measured. The Division will require the tailings in the TSF to have a pH between 6.5 and 9 and the Operator will be required to demonstrate that the tailings are with the required pH range prior to final reclamation of the TSF. 16. Please describe the activities that will be conducted in the laboratory. 6.3.4 Exhibit D — Reclamation Plan 17. The proposed reclamation seed mix only includes grass species. The Division believes the addition of tree, shrub and forb species to the reclamation seed mix could enhance the site's use as wildlife habitat. Please respond. 18. The Applicant is proposing to place 18 inches of suitable material over the TSF prior to seeding. Is the material to be placed over the TSF currently on the site? If so, where is the material being stored and what is the source of the material? If the material will be imported, then the Applicant will need to comply with the requirements of Rule 3.1.5(9) regarding the importation of inert fill material. 19. The final cap placed over the TSF must be designed to have positive drainage. Please provide a cross section drawing showing that the cap will have a crown and will provide positive drainage across the TSF.