2007-12-19_REVISION - C1981010

• Permit No: C1981010
• IBM Index Class Name: REVISION
• Doc Date: 12/19/2007
• Doc Name: Adequacy Concerns & Cost Estimate
• From: DRMS
• To: Trapper Mining Inc
• Type & Sequence: RN5
• Media Type: D
• Archive: No

CIRCES Cost Estimatina Software
PROJECT IDENTIFICATION
Task # : 127
State : Colorado
PermiVjob # :C-1981-010
sheet 1 of 2
QUANTITY UNIT
Blast area configuration description
Blasting method description Wedge-shaped mass
Cast blast
t
Highwall or bench face angle 0.
71
Regraded slope angle 3.00
Highwall or bench length 5,300

Highwall or bench width (from vertical line at base of desired cut on highwall face)
180 T
Highwall or bench height (from pit floor to crest) 120.0
Depth to base of cut at highwall face 0.0 .
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BLAST AREA VOLUMES "
BLAST AREA DESIGN
QUANTITY UNIT
Recommended blasthole diameter 8.00 inches
Selected blasthole diameter 10.62 inches
Subdrilling allowance 0.0 feet
Blasthole depth (avg. depth of holes on wedge-shaped mass) 24.8 feet
Density of rock Cast blasting (AN rock density
Burden to Charge Diameter Ratio 20 times diameter
Burden 18.0 feet
Spacing to Burden Ratio 1.1 times burden
Spacing 20.0 feet
Cubic yards of rock per blasthole (avg. quantity per hole on wedge-shaped mass) 358.28 cubic yards
Powder factor description Cast blasting rock strength
Powder factor 2.150 pounds/cu.yd.
Densityof blasting agent 0.85 grams/cc
Quantity of explosives per blasthole (avg. quantity per hole on wedge-shaped mass) 770.31 ounds
Height of powder column per blasthole (avg. height per hole on wedge-shaped mass) 23.58 feet
Height of stemming per blasthole (avg. height per hole on wedge-shaped mass) 1.22 feet
Stemming to burden ratio (avg. ratio per hole on wedge-shaped mass) 0.07 t imes burden
Quantity of stemming per blasthole (avg. quantity per hole on wedge-shaped mass) 0.0279 cubic yards
Number of rows
8 r ows
Number of blastholes per row 265 holes per row
Total number of blastholes 2,120 h oles
Total length of all blastholes 52,576 f eet