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TETRA TECH RMC Mr. Larry Oehler Adequacy Response M-2004-044 November 22, 2004 Page 7 of 20 has reviewed and accepted the final slurry wall construction report, including quality assurance test results. Phase 1 is excluded from this condition, as a slurry wall in not intended to contain this area. We believe this commitment satisfies the conditions outlined in the August 29, 2004 Memorandum. The Stability Analysis was re-run using the soil parameters outlined in the August 29, 2004 Memorandum. The Revised Report dated November 22, 2004 is attached for your review. 11. The application indicates that materials imported from other Aggregate Industries mines may be processed in the proposed permit area. Address Rule 3 Section 1.5(9), as it relates to reclamation fill material that may be generated from the imported materials. Page D-3 of the application states "AI may process materials imported from other sites. The applicant is aware that in accordance with Rule 3.1. S(9) of the Construction Material Rules and Regulations, if any offsite material is used as backfill, a notarized letter will be submitted to the Division indicating the materials are inert. The applicant will supply such a letter to the Division if, at the time of Reclamation, the applicant intends to use off-site material as backfill. " If any imported materials are used for backfill, the Applicant will submit a notarized letter which will include the information outlined in Rule 3.1.5(9). 12. Show on the mining plan maps the location and dimensions of dewatering trenches far Phases 2, 3 and 3A and the location and dimensions of the settling ponds used to settle sediments prior to discharge. Locations aze shown on mining plan. The locations of the settling ponds will vary for each mining area; however for reclamation cost estimating the maximum settling pond size is 5 acres. The maximum dewatering trench constructed or disturbed at any given time is 3-4 feet wide, 15 feet deep and approximately 4,000 linear feet. 13. The Urban Drainage and Flood Control District has constructed a riverbank stabilization project along the southern reach (Morgan Smith Natural Area). According to UDFCD guidelines for grave[ mining activities within the 100 year floodplain, no mining shall occur within 200 feet unless pit side bank stabilization or a spillway is constructed, in addition to river bank stabilization. The UDFCD requests that Aggregate Industries add a note to the application that "Mining limit without further approval of UDFCD and DMG be shown at a 200 feet setback from the riverbank. " (See UDFCD letter to DMG dated 8-6- 04 and forwarded to Tetra Tech 8-10-04) Please make the necessary requested changes to the application narrative and plan maps or obtain approval, in H:~i919_019_OIUILR-\DMG Response\I st Adequacy Response to DMG I1-5-04.doc