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sheet 1 of 2 <br />CIRCES Cost Estimating Software <br />SURFACE BLASTING WORK <br />PROJECT IDENTIFICATION <br />Task # : 001 State : Colorado Permit/job # : C-1981-019 <br />Date : 0910212009 County :Moffat Abbreviation :none <br />User : JRS Site: Colowyo Mine Filename :C019-001 <br />Agency or organization name : Colorado Division Of Reclamation, Mining And Safety <br />Permit or other job action :Permit Renewal 05 <br />Task description :Drill and Shoot West Pit Highwall (Cast Blast) <br />BLAST AREA DIMENSIONS <br /> QUANTITY UNIT <br />Blast area configuration description Box-shaped mass <br />Blasting method description Cast blast <br />Highwall or bench face angle 2.00 h:1v <br />Regraded slope angle NA h:1v <br />Highwall or bench length 5,000 feet <br />Highwall or bench width (from vertical line at base of desired cut on highwall face) 150 feet <br />Highwall or bench height (from pit floor to crest) 75.0 feet _ <br />Depth to base of cut at highwall face 50.0 feet <br />BLAST AREA VOLUMES <br />QUANTITY UNIT <br />Total volume of dimensional mass to be shot 925,926 cubic yards _ <br />Blast volume to subdrill grade and blast pattern lines 814,489 cubic yards <br />----- --- ---- -- -------- <br />Blast volume to finish grade and blast pattern lines 814,489 cubic yards <br />Remaining volume required to be re-shot or ripped 111,437 cubic yards <br />BLAST AREA DESIGN <br /> QUANTITY UNIT <br />Recommended blasthole diameter 6.67 inches <br />Selected blasthole diameter 9.00 inches <br />Subdrilling allowance 0.0 feet <br />Blasthole depth (avg. depth of holes on wedge-shaped mass) 50.0 feet <br />Density of rock Average Density R rock density <br />Burden to Charge Diameter Ratio 25 times diameter <br />Burden 19.0 feet <br />Spacing to Burden Ratio 1.1 times burden <br />Spacing 21.0 feet <br />Cubic yards of rock per blasthole (avg. quantity per hole on wedge-shaped mass) 738.89 cubic yards <br />Powder factor description Medium rock strength <br />Powder factor 0.575 pounds/cu.yd. <br />Density of blasting agent 0.85 grams/cc _ <br />Quantity of explosives per blasthole (avg. quantity per hole on wedge-shaped mass) 424.86 pounds <br />Height of powder column per blasthole (avg. height per hole on wedge-shaped mass) 18.12 feet <br />Height of stemming per blasthole (avg. height per hole on wedge-shaped mass) 31.88 feet <br /> <br />Stemming to burden ratio (avg. ratio per hole on wedge-shaped mass) <br />1.68 _ <br />times burden <br />Quantity of stemming per blasthole (avg. quantity per hole on wedge-shaped mass) 0.5216 cubic yards <br />Number of rows 3 rows <br />Number of blastholes per row 238 holes per row <br />Total number of blastholes 714 holes <br />Total length of all blastholes 35,700 feet