10 BULLETIN 300, U. S. DEPARTMENT OF AGRICULTURE. 
Contractors, in determining the cost of installing a machine on a 
job, usually charge to the new project the cost of moving the machine 
from the last location. The cost of installation varies greatly with — 
the type of machine and is greatest when a floating dipper dredge is 
used. For each size and type of machine there is a minimum yardage 
below which the machine can not be installed and operated economi- 
cally.. 
Contractors consider the life of a machine as from 3 to 5 years, 
depending upon the operators. Some consider if a new machine is 
used that the job must pay for the machine as well as render a profit. 
Other contractors allow 25 per cent depreciation each year for four 
years on floating dipper dredges, while still others allow 50 per cent 
the first year and then 124 per cent per year for four years. For dry- 
land excavators most contractors assume depreciation at 20 per cent 
per year. | | 
The item of repair is distinct from depreciation, and is related to 
the character of the soil and the project conditions rather than to 
the life of the machine. Repairs on a machine operating in a timber 
country obviously are greater than when operating in open country. 
A distinction should also be made between repairs and renewal of 
equipment; thus, a new boiler for a dredge should not be charged 
to repairs, but rather to renewal of equipment. Cable renewals are 
an important factor in the operation of any type of machine, and 
a record of the life of cables of various makes and grades in differ- 
ent kinds of soil is of great value in estimating work. The following 
items should be included in an estimate of cost: 
Time required to complete project. 
Time lost, due to adverse weather conditions. high water, breakdowns, ete. 
Cost of securing contract. 
Installation : 
Dismantling dredge and hauling te siding. 
Freight. 
Assembling hull, labor, and hauling. 
Hauling machinery and installing. 
Building cabin boats, coal barges, and launch. 
Clearing right of way and dynamiting stumps. 
Operation : 
Wages of crew. 
Subsistence for crew. 
Fuel and supplies: 
Coal— 
Cost at mine. 
Cost of freight. 
Cest of hauling to dredge. s 
Oil, waste, and grease. 
Repairs, new cables, ete. 
Depreciation. 
