Hourly Operating Costs
Hourly operating costs are considered variable and are directly related to
daily use. The operating costs assume the equipment is working a full
operating hour under average operating conditions. Procedures for adjusting
these costs for other conditions or for other economic situations are
explained in How to Use the Cost Calculator. The cost of operator time is
not included. It must be added separately.
Overhaul Parts
Overhaul parts costs for mobile equipment are those associated with scheduled
reconstruction and/or replacement of major components such as engines and
transmissions. For stationary processing equipment, the costs are for
scheduled refurbishing or replacement of major wear components such as
drives, support frames, and vessels. The value is based on the following
relationship:
Hourly Overhaul Parts Cost = ((Capital Cost × F) ÷ H)*C
Where: F = experienced-based factor
H = typical annual operating hours
C = scale coefficient
Overhaul Labor
Overhaul labor costs for mobile equipment are those associated with
scheduled reconstruction and/or replacement of major components such as
engines and transmissions. For stationary processing equipment, the costs
are for scheduled refurbishing or replacement of major wear components such
as drives, support frames, and vessels. The value is based upon the
following relationship:
Hourly Overhaul Labor Cost = Overhaul Parts Cost × F × L
Where: F = experienced-based factor
L = overhaul labor hourly wage plus benefits(dollars per hour)
Maintenance Parts
This item represents those costs associated with both unscheduled repairs and
scheduled servicing of both minor and major components, excluding overhaul
activities. These include all aspects of machine maintenance exclusive of
fueling, lubrication, tire replacement, and maintenance and replacement of
those parts directly to impart energy (see wear parts). The value is based
upon the following relationship:
Hourly Overhaul Parts Cost = ((Capital Cost × F) ÷ H)*C
Hourly Maintenance Parts Cost = ((Capital Cost × F) ÷ H)*C
Where: F = experience-based factor
H = typical annual operating hours
C = scale coefficient
Maintenance Labor
This item represents a typical charge per hour of operation to cover
mechanics' time to perform maintenance and repair functions, exclusive of
overhaul work. The value is estimated by the following relationship:
Hourly Maintenance Labor Cost = Maintenance Parts Cost × F × L
Where: F = experience-based factor
L = repair labor hourly wage plus benefits (dollars per hour)
Fuel/Power
These items list the cost per hour for diesel fuel, gasoline, electric power,
or natural gas as appropriate. Care should be taken to note whether an "n"
or "y" is listed in the "Motor Included" column. If an "n" is listed, a
motor is required, but the costs to operate are not included here. In this
case an appropriate motor should be selected from the Miscellaneous
Equipment list, and both its capital and operating costs added to the
estimate. Costs for each fuel type are determined by the following
relationships:
Diesel Fuel
The cost per hour for diesel fuel required to operate the equipment under
average conditions is estimated by the following relationship:
Diesel Fuel Cost per Hour = Engine Horsepower × F × D
Where: F = experience-based factor
D = diesel fuel price (dollars per gallon)
Gasoline
The cost per hour for gasoline required to operate the equipment under
average conditions is estimated by the following relationship:
Gasoline Cost per Hour = Engine Horsepower × F × G
Where: F = experience-based factor
G = gasoline price (dollars per gallon)
Electric Power
The cost per hour for electric power required to operate the equipment under average conditions is estimated by the following relationship:
Electric Power Cost per Hour = Motor Horsepower × F × 0.746 KW per horsepower
× E
Where: F = average electric power draw (factor)
E = electric power price (dollars per KWH)
The electric power price (E) includes demand and service charges as well as
energy charges.
Natural Gas
The cost per hour for natural gas required to operate the equipment is
determined by the following relationship:
Natural Gas Cost per Hour = (E ÷ 1,040,000 btu's/MCF) × N
Where: E = Energy requirement (btu's per hour)
N = Natural gas price (dollars per MCF)
Lube
The hourly cost of crankcase oil and other lubricants required to operate the
equipment is estimated by the following relationship:
Lube Cost per Hour = (Capital Cost ÷ FL) + (((Engine HP ÷ FC) × L) ÷ I)
Where: FL = experience-based equipment lube factor
FC = experience-based crankcase oil factorL = lube price (dollars per
gallon)I = lube change interval (hours)
Tires
Tire costs assume that each tire will be retreaded two times before being
replaced with a new tire. The cost of a retread is assumed to be 75% the
cost of a new tire, and the life expectancy about nine percent less. The
hourly cost for tires is calculated by the following relationship:
Tire Cost per Hour = ((N tires × T) + (2 retreads × (0.75 × T × N tires))) ÷
(L hours + ((2 retreads × L hours) ÷ 1.1))
Where: N = number of tires required by vehicle
T = tire priceL = expected tire life
Wear Parts
Costs in this column typically refer to the costs of parts that directly engage rock and impart some form of energy intended to change the character of the rock. These include items such as drill bits, dozer blades, excavator teeth, crusher and impactor liners, and grinding media. Hourly wear rates are highly variable (depending on the nature of the rock) and should be adjusted accordingly. Wear rates assumed here are considered average for hard-rock mining and mineral processing operations. The relationships used to provide the Wear Parts costs are specific to the machine and take the form:
Wear Parts Cost = Pc × Hc
Where: Pc = cost of the parts (drill bits, grinding balls, bucket teeth)
Hc = parts consumed per hour
Total
The total operating cost comprises the sum of the eight operating cost items listed. It does not include depreciation, overhead, insurance, or cost of facilities capital. Nor does it include the cost of equipment operators.