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Janice Lynn Bennett - 81422.PDF Page 22 <br />Blasting Impacts Assessment for the Proposed GCC Rio Grande, Inc Quarry in Pueblo County, Colorado <br />For the past three years, the author has also been involved in an expansion projed at the <br />County of Sonoma California Central Disposal Site in Petaluma, CA, where blasting has <br />been regularly occurred within 1,000 feet of dairy cows. M easurements in the cow pastures <br />have indicated that blast noise and vibration levels have been as high as 0.08 in /s and 128 <br />dBL, respectively. Despite initial concerns by the dairy operators, all involved parties have <br />now concurred that the cows have not been disturbed in any way by these blasting effects <br />At the Red Rock site, all domestic animals located more than 4,000 feet from planned blast <br />areas will experience maximum levels of ground motion of around 0.05 in /s [240(4,000/(360) <br />O. Intensities of air - overpressure for 6.75 -inch charges, stemmed with at least 6 feet of <br />crushed stone stemming, will likely not exceed 115 dBL at distance greater than 4,000 feet. <br />Based on the referenced studies and observations of the author at many other projects, <br />blasting at the Red Rock Project will have little or no impact on domestic animals at the <br />Blake Ranch or at other more distant neighboring properties. <br />3.6 Control of Dust <br />In provisions describedcontained in the GCC Air Permit, Construction Permit No. <br />98PB0893, commitments are maderequirements are in place to use water injection when <br />drilling to control drilling dust, and sequential delay timing schemes to minimize blasting <br />dust.Despite these measures, blasting will produce some amount of airborne dust. However, <br />theamount of blast dust can be further mitigated in several ways. From experience gained <br />from in Clark County, Nevada, during very dry and arid seasons, it has been found that the <br />amount of dust produced by blasting can be dramatically reduced by carefully excavating <br />loose dirt and soil from the rock before blasting. Since limestone quarriesFurther, since <br />limestone quarry operators like GCC Rio Grande invariably remove loose overburden to <br />prevent dilution of mined rock, it unlikely that airborne dust from blasting will be a cause of <br />concern. <br />4.6 Impacts on Soil Resources <br />Some small amounts of blasting agents, which in quarries is typically ammonium nitrate <br />pellets mixed with fuel oil (ANFO), is lost to the ground by spillage or wind blowingit while <br />being loaded. The amount on nitrates released to the ground by these losses is typically not <br />toxic to any flora or fauna in an arid environment like that existing at the Red Rock site. <br />Wind -blown ANFO dust that lands on the ground surface effectively becomes fertilizer for <br />plants that convert it to other natural matter through photosynthesis. This amount of <br />nitrates from this source is usually much less than that created by mass fertilizing of <br />agricultural crops or nitrates produced from urea in animal urine. If CGG implementsGCC <br />REVEY Associates, Inc <br />Page 19 July 2002 <br />