Laserfiche WebLink
Blasting Impacts and hock Slope Stability Assessment for Cottonwood Quarry in Grand County,CO <br /> Chemical Contamination of Ground Water and Surface Water <br /> Most commercial explosives contain 70 to 9411/9 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 /> quality criterion is 0.02-mg/L free-ammonia and the drinking water criterion for nitrate as <br /> nitrogen (NO37"N) is 10-mg/L. At the Cottonwood site, if normal industry standards of care <br /> concerning clean-up procedures are used to recover any spilled explosives materials like 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, rules and safety <br /> procedures. In Colorado, the Division of Oil and Public Safety administers the testing and <br /> licensing 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 April 2004 <br />