APPCOR10883

• Permit No: C1981039
• IBM Index Class Name: Application Correspondence
• Doc Date: 12/10/1984
• Doc Name: GRASSY GAP BONDING CALCULATION
• Media Type: D
• Archive: No

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• •
GRASSY GAP MINE, BRUEGGEN PIT (No. 4)
Anticipated Final Backfilling ~ Topsoiling Costs
Assume 250,000 C.Y. of subsoil and 45,100 C.Y. of topsoil
Stockpile to backfill and topsoil area respectively
Maximum haul = 2000 L.F. (Most likely haul under 1000 L.F.). Average
elevation 7500. Avd. grade = 8°!,. Spread of equipment composed of
Cat 6310, Scrapers, Cat D-9L & Cat D-8K Tractor Dozers, Cat 14C Pfotor
Grader.
All calculations based upon information contained in Caterpillar Performance
Handbook, Edition 12.
Rolling resistance estimated from table page 501 = 5%
Altitude operating from Table Page 504 = 100%
Total effective grade loaded = 8% grade
Assistance - S% rolling resistance = 3% favorable
Total effective grade empty = 8% + 5% = 13% unfavorable
For loaded [ravel time:
From retardar curve, page 186 with 3% effective grade and 75,000~i
loaded scraper, speed = 31 MPH.
Haul travel time, therefore =
2000 Feet = .73 Min.
31 MPH (88 FPM/MPH)
For empty travel time:
From travel time curve, page 188 with L3% total resistance and 2000
for haul
Return travel time, threrfore = 2.3 Min.
Pusher - Scraper combination:
From page 449
Boost time = .10 Minutes
Return time = 40% of load time
Maneuvering time = .15 Minutes
Pusher cycle time = 140% of load time + .25 Minutes
Load time from chart page 166 = .6 Minutes
Pusher cycle time = 1.4(.6) + .25 = 1.09 Minutes
Scraper cycle time = load + haul + maneuver b spread + return
Maneuver and spread time from page 166 = .7 Minutes
Scraper cycle time = .6 + .73 + .7 + 2.3 = 4.33 Minutes
Number of scrapers handled by each pusher = 4.33 Min. = 3.97 or
1.09 ?Sin. 4 scrapers