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Blasting Impacts and Rock Slope Stability Assessmcnt for Cottonwood Quarry in Grand County, CO <br />4.4 Human and Animal impacts <br />As established in the prior section, respective vibration and air -overpressure intensities at the <br />nearest dwellings are not expected to exceed 0.09 in/s and 122 dBL. <br />Human Resy2M to Blastin <br />.Since the duration of quarry blasts rarely exceed two seconds, the Wiss-Curves (see Figure 3.5) <br />indicate that ground vibration, at the nearest offsite dwelling, with levels around 0.09 in/s will be <br />in the barely detectible range. Since Colorado State Rules limit blasting to daytime hours when <br />ambient levels of background noise and vibration are high, neighbors to the blasting will most <br />often not even know it has occurred. <br />Impacts on Animals <br />While visiting the site, the author observed pastureland, where domestic animals may feed or <br />range, on adjacent properties. Accordingly, some neighbors might express concerns about <br />potential blasting impacts on domestic and wild animals. Several years ago the author <br />participated in a controlled study regarding the impacts of blasting on a variety of animal species <br />conducted by animal biologists at the Washington Park Zoo in Portland, Oregon. In this study, <br />researchers evaluated the effects of nearby (as close as 500 ft) blasting noise and vibration on <br />black rhinos, naked mole rats, elephants, spotted owls, snow leopards, red pandas and several <br />other species (Sbepherdson et al, 1998). Elephants were specifically chosen for this study <br />because they are known to communicate at infiasonic noise frequencies below human hearing <br />range. The black rhinos were studied because zookeepers were concerned that blasting might <br />aggravate the problems with a pair that was unsuccessfiil at breeding during the year prior to the <br />construction work. The physiological effects of blasting were evaluated by measuring the level <br />of the stress hormone (cortisol) found in animal scat, before and after blasting. In addition, for <br />the first six blasts, the physical reactions of the tested animals were observed when blasting <br />occurred. The intensity of blast -induced ground motion in this study was as high as 0.68 in/s, <br />which is more than 7 times higher than the 0.09 -ids level expected for the Cottonwood Quarry. <br />Maximum air overpressure for this blasting was about 130 dBL (Linear scale) and ground <br />motion reached about 0.25 in/sec. The researchers noted that the tested animals noticed the first <br />blast or two, however they quickly acclimated to the noise and vibration. Additionally, the black <br />rhinos mated successfully for the first time while construction was occurring on the tunnels. In <br />their final conclusions, the researchers found that the tested animals experienced no long term <br />negative effects from the levels of noise and vibration produced by the construction blasting. <br />From the authors' personal experience, white-tailed deer were observed, on many occasions, <br />within several hundred feet of an open-air explosive testing range at the Reynolds Plant of the <br />former Atlas Powder Company in Tamaqua, Pennsylvania. The peak air overpressures, during <br />unconfined explosive tests, at that distance often exceeded 145 dBL. When blasts were detonated <br />REVEY Associates, Inc. Page 16 April 2004 <br />