Khai thác mỏ lộ thiên - The bucket dredger

Được đăng lên bởi Trieu Thang
Số trang: 25 trang   |   Lượt xem: 1944 lần   |   Lượt tải: 11 lần
6. The bucket dredger

Figure 6- 1


General Considerations

The bucket dredger is one of the mechanical dredgers.
A bucket dredger is a stationary dredger that is equipped with a continuous chain of buckets, which
are carried through a structure, the ladder (Figure 6- 2. This ladder is mounted in a U-shaped pontoon.
The drive of the bucket chain is on the upper side. The bucket dredger is anchored on six anchors.
During dredging, the dredger swings round the bow anchor by taking in or paying out the winches on
board. The buckets, which are filled on the underside, are emptied on the upper side by tipping their
contents into a chute along which the dredged material can slide into the barges moored alongside.
The chain is driven by the so called upper tumbler at top of ladder frame, which is connected either
via a belt to the diesel or directly to an electro motor or hydro-motor.


Figure 6- 2
Since 1960, bucket dredgers ( also called bucket line dredge(r) or bucket chain dredge(r)) that were
much used before the Second World War, have been almost entirely replaced by Backhoe dredgers or
trailing suction hopper dredgers and cutter suction dredgers. The reason for this is that the bucket
dredger, with its six anchors, is a big obstacle to shipping. Moreover maintenance costs are high and
the bucket dredger requires many highly skilled operatives. But above all, their production has not
kept pace with the increase in scale that has taken place in the suction dredgers.

6.2. Area of application
Bucket dredgers are only used in new or maintenance dredging projects when the initial depth of the
area to be dredged is too shallow for trailing suction hopper dredgers and the distances involved are
too long for hydraulic transport. For environmental projects, which require the dredging of ‘in situ
densities’, the bucket dredger is suitable peace of equipment.
When dredging for construction materials such as sand and gravel, or for minerals such as gold and
tin ores, bucket dredgers are still frequently used.
Bucket dredgers also come in a variety
of types. For example:
• Dredgers with or without the
means of propulsion (Figure 6- 3)

Dredgers with a conveyor belt
system (Figure 6- 4)


Dredgers with equipped with

Figure 6- 3


Figure 6- 4
The maximum dredging depth is highly dependent on the size of the dredger. There are dredgers with
a maximum dredging depth of more than 30 metres. Such large dredgers the minimum dredging depth
is often 8...