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Jerry Schnabel, Bob Stabo <br /> July 11, 2016 <br /> Page 3 <br /> located on either side of the fault appear to be completed in two separate ground water systems, <br /> which is to be expected based on the geology of the two areas (fractured granite versus sandstone <br /> formations). Ground water elevations from well records indicate that the wells to the west of the <br /> property are controlled mainly by Little Turkey Creek and its associated fracture system,while the <br /> sandstone wells are less controlled by and less connected to the Little Turkey Creek system, <br /> indicating that little to no hydraulic interaction occurs between the two ground water systems on <br /> either side of the fault. <br /> As indicated in the CDRMS preliminary review letter dated May 27, 2016, "the question of <br /> whether or not the fault zone acts as a hydrologic barrier is not as critical given the Division's <br /> requirement for the operation to develop and implement a groundwater monitoring program. <br /> Under this program, existing groundwater conditions will be characterized before mining begins, <br /> and groundwater will be regularly monitored for impact." We agree that the monitoring plan will <br /> identify actual effects of the mining on the local ground water system, but still believe that the <br /> characteristics of the existing faults will mute any effects of the mining on the other(eastern) side <br /> of the fault. <br /> Potential Impacts from Blasting at the Quarry <br /> Comment: Several of the respondents expressed concern regarding the short-term and long-term <br /> impacts of blasting operations at the proposed quarry on their water supplies. Concerns <br /> associated with the impact of blasting include impacts to well structures, well yields and water <br /> quality. Supportfor these concerns included reference to well yield decline associated with a 2008 <br /> Westclie earthquake and water quality observations associated with other nearby blasting. <br /> Response: Any blasting that will be performed at the site will need to follow State guidelines <br /> regarding blasting operations and will be performed by a certified blasting contractor. The State <br /> guidelines are designed to protect surface structures. Based on information available from the <br /> Society of Explosive Engineers, subsurface structure response to ground waves from blasting will <br /> be less than surface structure response to ground waves, so the guidelines designed to protect <br /> surface structures will also protect any subsurface well structures'. Accordingly, there should be <br /> little, if any, concern regarding damage to well structures related to the blasting operations. <br /> Seismic instruments will be installed at or near the eastern and western property boundaries to <br /> measure ground vibration and peak particle velocity and ensure that State guidelines are met. <br /> The purpose of the blasting that will occur at the proposed quarry is to locally fracture the in-situ <br /> granite material to facilitate mining. The radius of influence of the blasting will be based on the <br /> size and spacing of the charges, but should be constrained to the mining area. Accordingly, <br /> fracturing of the bedrock material should not extend beyond the quarry area and should not impact <br /> the local aquifers. <br /> One of the public comments referenced a 2008 earthquake in Westcliff,Colorado which allegedly <br /> resulted in the failure and replacement of a water supply well in the area of the proposed quarry. <br /> Additional information provided by the commenter indicated that their well production dropped <br /> ' The World of Explosives. (2015). Frequently Asked Questions. Retrieved June 7, 2016, from <br /> http://explosives.org/frequently-asked-questions/(http://explosives.org/frequently-asked-questions/ <br />