Correct Answer - Option 1 : Drag line
Concept:
Drag line:
The basic character of this machine is dragging the bucket against the material to be dug, it is called as drag line. A drag line has distinct advantages compared with a power shovel because of its long light boom. It is used for the construction of ports, for excavations underwater, sediment removal in water bodies, etc.
Advantages:
- A drag line usually does not have to go into a pit or hole for excavating the earth. It may operate on natural firm ground. Therefore it is more useful when the earth is removed from a ditch, canal or pit containing water.
- When the excavated earth is to be deposited on nearby banks or dams, it is better to use drag line with a long boom enough to dispose of the earth in one operation, eliminating the need of hauling units thereby reducing the cost of handling the earth.
- A drag line is excellent for excavating trenches without shoring.
Comparison between all different types of excavating equipment:
Item of Comparison
|
Power Shovel
|
Back Hoe
|
Drag line
|
Clam Shell
|
Excavation in hard soil or rock
|
Good
|
Good
|
Not Good
|
Poor
|
Excavation in wet soil or mud
|
Poor
|
Poor
|
Moderately good
|
Moderately good
|
Distance between footing and digging
|
Small
|
Small
|
Long
|
Long
|
Loading Efficiency
|
Very Good
|
Good
|
Moderately good
|
Precise but slow
|
Cycle time
|
Short
|
Sightly more than power shovel
|
More than power shovel
|
More than the other equipment
|