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Blasting lv pacts and Rock Slope Stability A=sawmt for Cottonwood Quarry in Grand County, CO <br />Chemical Contamination of Ground Water and Surface Water <br />Most commercial explosives contain 70 to 94% ammonium nitrate, by weight If significant <br />amounts of explosives are spilled or incompletely detonated, rainwater will cause some amount <br />of ammonia and nitrate to leach out and go onto into the ground. Over time, leached ammonia <br />and nitrates will penetrate into ground water and can possibly be washed by rainwater over the <br />ground surface and into surface and ground water resources. The U.S. EPA ambient water <br />duality criterion is 0.02-mg/L free -ammonia and the drinking water criterion for nitrate as <br />nitrogen (N% --N) is 14-mg/L. At the Cottonwood site, if normal industry standards of caro; <br />concerning clean-up procedures are used to recover any spilled explosives materials fare ANFO <br />or emulsion slurry explosives, and charges are adequately primed with cast -booster primers, <br />losses of ammonia and nitrates to ground water or flowing surface water will be minimal. The <br />author has visited many existing quarries with operating conditions similar to that of the <br />proposed Cottonwood Quarry, and knows of no significant water contamination incidents at these <br />operations, many of which have operated for over 20 years. If industry -standard explosive -spill <br />clean-up procedures are applied, blasting will have no impact on surface water or on the <br />condition and quantities of water pumped from wells. <br />4.2 Security of Explosive Materials <br />Linke Construction Co. plans to have blasting work done by a subcontractor. Hence, no <br />explosive materials will be stored at the site. The blasting contractor will deliver adequate <br />quantities of explosives to the site on days when blasting is planned. All unused explosives and <br />detonators will be returned to the blasting contractor's secure offsite magazines. <br />As required by Department of Transportation (DOT) rules, explosive materials would be <br />delivered in specially built vehicles marked with United Nations (UN) hazardous materials <br />placards. Explosives and detonators are delivered in separate vehicles or they are separated in <br />compartments meeting DOT rules within the same vehicle. Vehicles contain at least two 10 - <br />pound Class -A fire extinguishers and all sides of the vehicles display placards displaying the <br />United Nations Standard hazard code for the onboard explosive materials. Drivers must have <br />commercial drivers licenses with Hazmat endorsements, and drivers must carry bill -of -lading <br />papers detailing the exact quantities and code dates of transported explosives or detonators. Once <br />explosives are delivered to the blasting site, the licensed blaster -in -charge is responsible for <br />directly overseeing their security. The blaster in -charge must have adequate experience and <br />successfully pass a licensing test verifying their knowledge of blasting methods, runes and safety <br />procedures. In Colorado, the Division of Oil and Public Safety administers the testing and <br />Homing of blasters. <br />Compliance with these rules by Linke Construction Co. and their subcontractors should provide <br />adequate security of explosive materials when used at the Cottonwood site. <br />REVEY Associates, Inc. Page 13 Apri12004 <br />