2008-01-28_REVISION - M1997054 (34)

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rip rap necessary for embankment erosion along the waterline during the SEO approval process using wave run-up calculations, etc. The bond will be revised after SEO approval to reflect 'wave run-up rip rap requirements: The slope stability report is included as Exhibit IV. 8. 9) -The operator agrees to seed topsoil stockpiles that remain in place for more than 180 days. 10) Two JA. Cesare Reports were previously: provided to. the Division of Reclamation, Mining, and Safety in support of the proposed granite reservoir. -In addition to the report, the operator has the experience and -expertise to be able to anticipate .the likelihood of natural flaws in the granite high wall as well as the experience and expertise to plug and/or' grout the flaws in the unlikely event that they are present: 11) A memo of the slope stability analysis performed by Lyman Henn, Inc..regarding the granite quarry mining slopes is attached as Exhibit IV.11. These calculations were performed both for the rock slope and for backfill on the benches. V) EXHIBIT G Water Information 1) A draft Groundwater Study has, been previously provided to the Division of . Reclamation, Mining; and Safety. This report has been revised to include analysis regarding the granite quarry and is attached to this letter as Exhibit V:1. 2) One permitted groundwater well exists within 600 feet of the permit boundary. This well is for.household-use and belongs _to Mark Brown. This well is located south of the site in the vicinity of the access road. No springs and seeps exist within 600 feet of the permit boundary. Exhibit V.2 is attached. 3) The sand and gravel mining operation is almost entirely above the invert elevation of the Arkansas River. One. area in a portion of the southeast corner is anticipated, to be potentially below the Arkansas River. Approximately 2.75 acres is less than two feet below the-invert ` elevation. of the Arkansas; approximately one acre is less than four feet below; and approximately 0.1 acres is more than four- feet below. This equates to an estimated amount of 8,000 cy of mineable material, which is approximately two days worth of mining. Dewatering this area for this small timeframe provides effectively no opportunity for significant impacts to the river. All dewatering efforts during this mining timeframe will pump the groundwater back to the Arkansas River. Front Range Aggregates commits that no kind of wet mining will take place. All necessary actions will be taken to avoid impacting the- river.. 4) The NPDES permit-was administratively extended. by'CDPHE until the Department can update it. The extension letter is attached as Exhibit V.4 and addresses the sand and gravel pit and the granite quarry.: Pumping will be into Tallahassee Creek and the Arkansas River. 5) The operator is not planning to construct a separate well water storage area for use on site. -Front Range Aggregates will update the :well, permit to include dewatering efforts. - The well location has been placed on the revised mining plan. -6) A copy of the FEMA approval letter will be provided to the Division of Reclamation, Mining,, and Safety upon receipt.