Estimating Dozer Operating
Costs
©2005 Dr. B. C. Paul
Application Notes
Severity of Duty
– Medium duty
Push loading scrapers
Land clearing
Pushing up soils and clays (such as trapping soil)
– Heavy duty
Rock ripping
Working on rock surfaces
Dozing Rock
Push loading scrapers through rock
Cost Component Fuel
D11 in heavy conditions uses 30-37
gallons (see Cat Handbook 35th ed page
20-13)
–
–
–
–
Idle time
Time in reverse
Down hill all reduce fuel consumption
Our conditions probably lower end 30 gallons
per hour
Cost for diesel (red dog)
– $1.85/gal
– 30gph*$1.85 = $55.5/hour
Cost Component Tires
Sucker!
– This is a track dozer
Undercarriage
On dozers tracks and underside are so
condition dependent that they need to be
calculated separately
Step #1
– Look up a basic cost per hour in Cat Tables
35 ed page 20-28
For my D11 basic factor is $18/hour
Step #2 pick adjustment factors for
impact, abrasiveness, and Z
Impact Factor
High corresponds to
– Impenetrable surface with 6 inch or greater
bumps (such as working on shot rock)
Moderate corresponds to
– Partially penetrable surface with 3 inch bumps
Possibly trapping rocking transition
Low corresponds to
– Completely penetrable surface few bumps
Possibly trapping top soil
My Dozer is working on rock pile High
– High is 0.3 (mod is 0.2 and low is 0.1) see Cat
Handbook ed 35 pg. 20-28
Abrasiveness Factor
High
– Saturated conditions with sand or sharp rock particles
(like working on shot rock)
Moderate
– Intermittently damp with few angular rock particles (soil
work might be like this)
Low
– Involves dry conditions with few rock particles
The dampness issue causes things to stick and
work into the joints of the treads
Number is H=0.4, M=0.2, L=0.1 (Cat Handbook
ed 35 pg 20-28)
– My dozer is working on shot rock 0.4
The Z factor
About 50% of Z factor is maintenance
– Range about 0 for absolute top maint
– 0.5 for maintain if it breaks
– I’ll go 0.25 for moderate
About 30% of Z factor is conditions
– Abrasiveness and impact with a little gut feel for how
rough
– I think this is rough 0.3
About 20% on operator temperament
– Race track backing, tight turns, running to side angle
are bad
– I’ll go middle of the road 0.1
Total up for my Z factor
– 0.65
Step 3 in Undercarriage Cost
Add up your 3 factors
– Impact 0.3
– Abrasive 0.4
– Z 0.65
– Total 1.35
Step #4 for Undercarriage Cost
Multiply the Basic Cost by the total of the 3 factors
$18/hr * 1.35 = $24.3
Breakdown on dollars (may be important for indexing)
– 70% parts, 30% labor
Labor was $60/shop hour
– High compared to about a $25/hr wage with 60% burden
– If I consider it includes my parts warehousing, secretarial and
supervision its probably reasonable
I better make sure I don’t count the personnel twice
Parts – Steel has gone up severely
–
–
–
–
I’m going to allow about 20% here
24.3 * 0.7 = $17.01
$17.01 *1.2 = 20.41
Add back the labor unaltered $20.41+ $7.29
$27.70/hr for Undercarriage Cost
Repair Reserve for Machine
Cat Handbook ed 29 pg. 21-36
– D11 is $19/hour for first 10,000 hours
– But D11 has 30,000 hour life under my
severe duty
– Multiplier for extended life is 1.3
– $24.70/hr
Lubricants Cost
D11 uses about 0.25 gallons/hr
– At $9.00/gallon lube $2.25/hr
13.5 lubricant changes/2000 hrs
– 2 labor hour per change at $60/hr
– 27*60/2000 = $0.81/hr
816 grease fittings/2000 hrs
– About 75 cents/fitting with labor
– 816*.75/2000 = $0.31/hr
Hourly Filter Cost $0.62/hr
53 Filters/2000 hrs
– 5 minutes per filter
– 4.42 hours/2000 hours
– At $60/hr $0.13/hr
Total it up $4.12/hr
Operator Cost
$25/hr with 60% burden $40/hr
Assuming that machine only runs
when operator is not on break (no
hot seat change out for 10 minute
breaks)
Total Operating Cost/hr
Fuel $55.50
Undercarriage $27.7/hr
Repair Reserve $24.7/hr
Lubricant $4.12
Wear parts $1.25 (guessed from
other examples)
Labor $40/hr
Total $153.27/hr