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MMRR Quarry, M-2004-067 <br />Response to Jan. 21 Adequacy Review <br />March 23, 2005 <br />Page 19 <br />relevant 200 foot boundary for Exhibit S, or if the new access point <br />removes this structure from the purview of Rule 6.4.19. <br />There are no structures within 200 feet of the mining limits of the proposed <br />quarry, processing area, or other areas of long-term production. The <br />reason for the inclusion of the structures listed under Exhibit S to date is <br />the definition of "affected area" to include the entry road. In this case, <br />implementation of the entry road will involve removal of rock and earth for <br />the sole purpose of clearing a grade into the site for vehicular access. <br />Construction of the entry road does not involve any risk of undermining the <br />listed structures, nor does it otherwise threaten the integrity of lateral <br />support for the noted structures within 200 feet. As discussed with Allen <br />Sorenson of the Division of Minerals and Geology relative to this project, <br />all grades along the final profile of the entry drive are at the same <br />elevation or a higher elevation than the listed structures. It is not <br />necessary to perform slope modeling to determine that activity within the <br />affected area will maintain adequate slope stability for these structures. <br />This is the natural result when no excavation occurs beneath the elevation <br />at the foundation of a structure. Additional technical analysis is not <br />necessary to determine that proposed grading in the affected area will not <br />cause damage to any of the listed structures. <br />Finally, according to Allen Sorenson, blasting vibration analysis should be <br />undertaken with initial blasting of the entry road. Small blasts may be <br />used to test the general magnitude of blast effects. If blasting for initial <br />construction of the entry road produces a peak particle velocity <br />demonstrably less than 0.75 ips at a structure, mine related activity can <br />continue without impact to Rule 6.4.19. Blast effects producing greater <br />than 0.75 ips at a structure will need to be mitigated though agreement <br />with the structure owner, alteration of blasting methods, or some other <br />solution to be approved by the DMG. Blast vibration analysis and the on- <br />going blast monitoring plan covering all affected areas and structures will <br />be submitted to the DMG prior to commencement of blasting, as noted in <br />response to adequacy comment under Rule 6.5, below. <br />6.5 Geotechnical Stability. <br />Division of Minerals and Geology adequacy comments related to mining <br />and reclamation of highwalls, blasting, and slope stability were issued in a <br />separate memo from Allen Sorenson to Tom Schreiner, dated January 25, <br />2005. We address these comments in the order presented. <br />1.) The applicant will commit to obtain approval of a blasting plan through <br />the technical revision process prior to the initiation of blasting at the <br />