EXCAVATING MACHINERY USED IN LAND DRAINAGE. vi 
The data in Table 2 were compiled from informatiorm furnished by 
the United States Reclamation Service. 
A drag-line excavator, having a 100-foot boom and a 34-yard bucket 
was operated by electricity on work in the Miami Conservancy Dis- 
trict. During two months’ operation, in which 149,186 cubic yards 
were excavated, the electrical energy consumed was 106,200 kw. h., 
or 0.71 kw. h. per cubic yard. 
In the operation of a 15-inch centrifugal pump,? having a 54-inch 
runner, a 500 horsepower synchronous motor, running at 720 revolu- 
lutions per minute, was used. The pump was run at two speeds, 250 
revolutions per minute and 300 revolutions per minute, the lower 
speed being used for discharge lines up to 1,500 feet long and to a 
lift of 10 to 12 feet, while the higher speed was used for greater dis- 
charge lengths and heads. The cutter head running at from 10 to 
20 revolutions per minute, was driven by a 50-horsepower slip-ring 
motor, and the main hoisting drum by a 30-horsepower motor of the 
same type. _Under average conditions the output was 5,600 cubic 
yards per day of two shifts, and the entire plant used approximately 
2 kw. h. per cubic yard. 
INTERNAL-COMBUSTION ENGINES. 
On the Rio Grande project the United States Reclamation Service * 
has been using drag-line excavators, operated by internal-combustion 
engines on the construction of drainage ditches. The ditches average 
10 feet deep, with 14 to 1 side slopes and have from 10 to 30 foot bot- 
toms. Three 8-hour shifts were run, each crew consisting of one 
operator, one engineman, and one helper. General repair and cleaning- 
up work was done on Sundays. In the construction of the ditches 
much quicksand was encountered. Table 3 gives operating data on 
14 cubic yard 50-foot boom drag-line excavators, mounted on cater- 
pillars. 
The total number of operating shifts for the four old machines 
using the 98-horsepower engines. was 3,592. Of this time 49 per 
cent was spent in actual digging, 38 per cent in repairing, and 13 
per cent in delays. The average excavation per shift of 8 hours was 
409 cubic yards. The total number of operating shifts for the 
four old machines equipped with the 125-horsepower engines was 
1,020. Of this time 60 per cent was spent in actual digging, 22 per 
cent in repairing, and 18 per cent in delays. The average ex- 
cavation per shift of 8 hours was 486 cubic yards. The-total number 
of operating shifts for the four new machines equipped with the 
125-horsepower engines was 679. Of this time 64 per cent was spent 
in actual digging, 19 per cent in repairing, and 17 per cent in delays. 
3Hng. News Rec., vol. 72 (1915), p. 186. 
4Tbid., vol. 83 (1919), p. 548. 
