EXCAVATING MACHINERY USED IN LAND DRAINAGE. 87 
sticky material than the solid type. It is made in five-eighths cubic 
yard size only. 
OPERATION. 
It is impracticable to give exact figures on the time required to 
assemble a drag-line excavator, as the time will vary greatly with 
the make of machine, the length of boom, and the style of mounting. 
Operators generally agree that more time is required to assemble a 
machine mounted on caterpillars than one mounted on skids and 
rollers. In general, the time required for 8 men to assemble a drag- 
line excavator varies from 1 week for the small 1-yard walking type 
to 6 weeks for a 34-yard caterpillar machine. The actual time con- 
sumed in erecting a 3-yard, 70-foot boom, walking, drag-line ex- 
cavator equipped with internal-combustion engines was 2,137 man- 
hours. The assembling by 12 men took 19 days. The machine made 
26 wagonloads and was hauled from the siding to the project, a dis- 
tance of 34 miles, in 9 days. ; 
The fuel consumption for drag-line excavators depends on the 
character of the soil and the distance of hoisting. The average con- 
sumption of fuel for both steam and gasoline operated drag-line ex- 
cavators has been given (Tables 12 and 13). 
Cable expense is greater on drag-line excavators than on floating 
dredges. The life of cables depends largely on the nature of the 
work, regardless of the size of machine. Some operators consider 
the life of a digging cable as about 25,000 cubic yards and of a hoist- 
ing cable about 100,000 cubic yards. Other operators state the life 
in days of double-shift operation. In earth a digging rope will last 
from 2 to 3 weeks and a hoisting rope from 1 to 2 months, depend- 
ing on the number of shifts and the condition of the sheaves and 
drums. In cemented sand and gravel a digging rope may wear out 
in 3 working shifts; usually in hard material its life is not longer 
than 10 shifts. 
The life of a cable is increased by proper lubrication. Incorrect 
lubrication or neglect of it results in increased wear within the rope. 
Even though the cable may appear bright and in good condition, 
this interior wear may be going on. The lubricant to be used de- 
pends upon the work which the cable is required to do. A hoisting 
cable which travels at considerable speed requires a different lubri- 
cant from track cables which move more slowly. 
Drag-line excavators with 50 to 60 foot booms operate more rapidly 
than machines with long booms of 90 feet or more. Therefore work 
which requires a short hoist and a small angle of swing can be done 
more rapidly than work which requires a long hoist and a large angle 
of swing. Rack-and-pinion swing machines have an advantage over 
