7. The drag cable can be reversed end for end to
prolong the life of the wire rope, reduce early wire rope
replacement, and keep wire rope cost down.
Remember, the drag cable should not be lubricated.
8. When lowering the dragline bucket into the area
to be worked, release the drag brake to tip the cutting
edge down and then release the hoist brake. You do not
have to drop the bucket to force the teeth into the
material. The bucket is filled as it is dragged toward the
crane by engaging the drag control lever. The cutting
depth is controlled by releasing tension from the hoist
brake. The dragline is NOT a positive digging tool.
9. The dragline cycle is filling the bucket, lifting
the bucket, swinging the loaded bucket, and dumping
10. Since the dragline is not a rigid attachment, it
will not dump materials as accurately as do other
excavators. When a load is dumped into a haul unit or
hopper, you need more time to position the bucket
before dumping it.
NOTE: When you are dumping into a haul unit,
NEVER load over the cab. Additionally, make sure the
operator is out of the cab and clear of the dragline or
11. The boom angle for dragline operations should
normally be from 25 to 35 degrees. However, check the
crane load chart to ensure this low boom angle does not
exceed the capacity of the crane. At this relatively low
boom angle, you must be careful when excavating and
dumping wet, sticky materials, because the chance of
tipping the crane is increased because the material tends
to hang in the bucket.
The dragline can be used in dredging where the
material handled is wet and sticky. It can dig trenches,
strip overburden, clean and dig road side ditches, and
When the dragline is handling
mud, it is the most practical attachment. Its reach
enables it to handle a wide area of excavation while
sitting in one position, and the sliding action of the
bucket eliminates trouble with suction.
Other uses of the dragline include the following:
1. In-line approach.
When excavating a trench
with the dragline, ensure the dragline and carrier unit are
centered on the excavation (fig. 12-48). The dragline
cuts or digs to the front and dumps on either side of the
excavation. The crane moves away from the face as the
2. Parallel approach. The dragline can slope an
embankment better by working it from the bottom to the
top. The crane is positioned on the top with the carrier
parallel to the working face, so it can move the full
length of the job without excessive turning.
3. Drainage. A dragline is ideal if earthwork
materials have to be removed from a trench, canal,
gravel pit, and so forth, containing water. Plan the work
to begin at the lowest grade point, so drainage will be
provided as the dragline progresses towards higher
NOTE: Digging underwater or in wet materials
increase the weight of the materials and frequently
prevent carrying heaped bucket loads.
Ditching the excavation through swamps or soft
terrain is common. Under these conditions the
excavated material is normally cast onto a levee or spoils
4. Loading haul units. When the job requires
excavated material to be loaded into hauling units, the
excavation should be opened up so loaded hauling
equipment can travel on high, dry ground or on better
grades. The spotting of trucks and dragline should be
planned for minimum boom swing with the truck bed
under the boom point and the long axis of the bed
parallel with the long axis of the boom or at right angles
to the boom. More spillage is to be expected from a
dragline than from a front-end loader.
Efficient Dragline Operation
Other uses of the dragline operation include the
1. Although the dragline bucket can be readily cast
beyond the length of the boom, the machine should be
positioned to eliminate casting.
2. Use heavy timber mats for work on soft ground.
The mats should be kept level and clean.
3. When setting up for a dragline operation, you
should have access for maintenance, operating
personnel, and hauling equipment.
4. Excavate the working area in layers, not in
trenches, and keep the slope upward toward the
5. Do not drag the bucket in so close to the crane
that it builds piles and ridges of material in front of the