Laserfiche WebLink
SUMMIT ENGINEERING C 0 1 ENGINEERS & LAND SURVEYORS <br /> Mail: P.O. Box 1897 Alamosa, CO 81101 P: 719-589-6147 E: summitengco@gmail.com <br /> pounds of explosives. This amount of explosive results in a ratio of approximately 1 to <br /> 1.11 tons of material produced per pound of explosive used. This indicates a rather <br /> heavy load ratio. On site testing may determine that they can use a lighter load than <br /> initially anticipated. <br /> The Dupont wasters'Handbook,fifteenth edition,indicates that in order to keep <br /> the velocity of vibrations caused by blasting within acceptable levels for structures <br /> located 200 feet from the blast, 92 pounds of explosive maximum should be used per <br /> each delay in a multiple delay shot. For structures within 300 feet, 116 pounds of <br /> explosives is the maximum per delay. At the nearest point of 250 feet to structures in this <br /> operation,the extrapolated maximum amount of explosives per delay is 104 pounds. A <br /> portion of the DuPont table is produced below to use as a guide for determining numbers <br /> of delays per shot: <br /> Distance for blast area to nearest Maximum quantity of explosives per <br /> structure, neither quarry owned nor shot for instantaneous firing or per <br /> leased,in feet. delay,for delay firing in pounds. <br /> too 75 <br /> 200 92 <br /> 300 116 <br /> 400 140 <br /> 500 176 <br /> 600 209 <br /> 700 259 <br /> goo 330 <br /> 900 403 <br /> 1000 495 <br /> 1200 770 <br /> The nine-to ten-hole shot pattern,fully loaded, would result in using at least 2 <br /> delays for the shot at the nearest location to the structures. When the face reaches its <br /> farthest distance to the structures of approximately 700 feet,259 pounds of explosives is <br /> the listed maximum amount per delay. Shot sizes and the necessary number of delays <br /> must keep the maximum amount of explosives per delay within the distant dependent <br /> quantities listed in the table. Using millisecond delays will also reduce the effects of any <br /> blasting seismic vibrations. <br /> If the recommendations are followed,there should be no damage to the structures <br /> mentioned above from the blasting operations. <br /> In addition,I recommend that the operator have an inspection completed of each <br /> of the structures mentioned including the residence 0.8 miles away prior to commencing <br /> any blasting operations. Note any structural problems such as cracks, dents, un-level <br /> structures,etc. Numerous pictures should be taken as part of this report with the proper <br /> date and time of the pictures noted. The reports and pictures could be invaluable should a <br /> claim arise in the future regarding damages due to blasting. <br /> 3 <br /> Job # 1200710MP - A Page171of78 <br />