2010-07-27_PERMIT FILE - M2009076 (26)

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• 4. Venture Resources has decided to provide for a sheltered Crusher Feed Pile. This will consist of a 6" thick concrete pad (30'x 32') with an .10" wide x 48" high concrete berm wall on each side and the back of the pad. This pad will be covered by a metal shed roof at a nominal height of 20'. Three sides will be metal siding, with the opening end protected from rain events by a closable canvas curtain. This will eliminate the need for liquid containment and stonnwater control. A new detail drawing, E15, has been included to show this structure and drainage grading around it. Exhibit C, D, and T have been updated to reflect his change. This entire stricture is to remain after reclamation as a storage shed, therefore demolition cost estimates will not be required for reclamation consideration. 5. A provision has been added to include a 60 mil, textured HDPE liner in the Water Holding Pond to facilitate cleaning of occasionally deposited mineral residue and to limit seepage through cracks in the shot-crete surface. See the revised Exhibit C, D, and T for details. 6. Exhibit I) has been revised to include a method and cost for handling process water elimination. See 6.3.4(1)(e). 7. A 500 gallon, skid-mounted, double walled diesel fuel storage tank has been specified for use. See revised Exhibit C and specification sheet added to the Exhibit C appendix. 8. Venture Resources has employed the expertise of TRl/Environmental, Inc. (TRI) and Advanced Terra Testing, Inc. (ATT) to perform the necessary geotechnical laboratory work to examine the tailings' physical and engineering properties as well as the interface relationship between the tailings, composite • liner components, and the existing site conditions. T1Z1's and ATT's findings and reports can be found in entirety as an appendix to the revised Exhibit C. Tailings impoundment design guidance was taken in part utilizing Steven G Vck's Planning, Design, and Analysis of Tailings Danzs, 1990 and the US Army Corps of Engineers Slope Stability, EM 1.110-2-1902. These authoritative works are cited in many EPA design and regulatory mandates. Exhibits C, T and E have been thoroughly revised. a. See revised Exhibit C for a more detailed description of the construction and process controls of the impoundment embankment shell. Cross-section details have also been revised in Exhibit Ell. b. Impoundment slope stability based on angle of repose has been abandoned. Design guidance using Wick's Planning, Design, and Analysis of Tailings Danzs and the US Army Corps of Engineers Slope Stability, EM 1110-2-1902 incorporated with the findings of TRI's and ATT's geotechnical analysis has replaced it for more sound impoundment slope stability design. See revised Exhibit C, T, and E. c. Exhibit EI I has been revised to more correctly illustrate tailings deposition zoning of coarse and slimes fractions. A description of process controls has also been incorporated into a revised Exhibit C. d. A GeoComposite liner layer will now be employed to facilitate leachate drainage, therefore eliminating the earlier proposed perforated pipe drains. Refer to the revised Exhibit C. e. Exhibit C has been revised to include a test plan to check emplaced tailings for proper consolidation. This looks at density and moisture content to verify consolidation level. 9. If geotextiles are used for reclamation revegetation, they shall be biodegradable. Exhibit C and D have been revised. 10. A grass seed mix and application rate has been developed specifically for this site through consultation • with the Natural Resource Conservation Service. Exhibit C and D have been revised and an MRCS seed mix specification has been attached as a new appendix to Exhibit D. Page 2 of 7