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Blast Vibration Analysis: Proposed MMRR Quarry Page 2 (c) where such structure is a utility, the Applicant may supply a notarized ' letter, on utility letterhead, from the owner(s) of the utility that the mining and reclamation activities, as proposed, will have "no negative effect" on _ their utility. Thus any DMG applicant that does meet the criteria of 6.4.19 Exhibit S (a) must comply with paragraph (b) and demonstrate that its activities will not adversely impact all significant, valuable and permanent man-made structures within its zone of influence. Clearly this includes the BHCCSD Wastewater Treatment Plant, its treatment appurtenances, and associated instrumentation aswell as the SDMD lighting structures. On behalf of Clear Creek District Water Providers, LLC, Lyman Henn Inc. submitted a preliminary Geotechnical Engineering Services Report for the proposed MMRR Quarry to Banks and Gesso, LLC and the Colorado DMG on August 19, 2005. DMG reviewed that submittal and provided Adequacy Review Comments (3`d) to the applicant via Banks and Gesso, LLC on September 12, 2005. In that review, DMG outlined a number of compliance options to assure that quarry operations will not damage offsite manmade structures. The September 12~' DMG response notes "[T]he ground vibration limitations imposed by compliance with any of the above four listed compliance options are designed to prevent damage as slight as the aggravation of existing minor cracks in plaster." This constraint reaffirms a DMG requirement cited in a January 25, 2005 Adequacy Review of the proposed quarry that stated, "[S]ince the development and production blasts will generate a low frequency (less than 40 hertz) component of ground vibration ,DMG will require that peak particle velocity (PPV) be less than 0.75 inches per second (ips) at structures not owned or controlled by the quarry operation and less than 0.5 ips at any older structures with plaster-on-lath walls that may be within the zone of influence of quarry blast ground vibrations." These PPV criteria originate in the 1971 U.S. Bureau of Mines study Blasting Vibrations and Their Effect on Structures, Bulletin 656. The Blasting Level Chart appended to the September 12`h DMG response derives from that report. As noted above, the 0.75 ips and 0.5 ips PPV limits are intended to prevent damage in drywall and plaster-on-lath walls respectively in residential structures. However, man-made structures [as defined in CMR I.1(98)] present within the proposed MMRR Quarry's zone of influence represent far more sensitive receptors than wood-framed residential housing. Subsequent sections of this report will describe the nature and operations of the BHCCSD Wastewater Treatment PSant and the SDMD lighting on State Highway 114 near the proposed MMRR Quarry. It will also identify certain sensitive receptors within the wastewater treatment plant and associated with the lighting fixtures. Finally, it will provide a geotechnical evaluation and detail potential impacts to the sensitive receptors from blasting operations at the proposed quarry. ©Leonard Rice Engineers, Inc. November 10, 2005 -Job No. 1086BCS03D