Mining

1. AERIAL ROPEWAYS
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AERIAL ROPEWAYS

2. Some Interesting Facts
• HAULAGE by rope and pulley has been known since
the earliest days, and although no graphic record is
available, the evidence has been furnished by
wooden pulleys found during excavations in Egypt.
These pulleys date from about 2600 B.C.
• The first practical aerial ropeway of which there is
any definite evidence was devised by Adam Wybe, a
Dutch engineer. During the construction of a fort at
Danzig he used an aerial ropeway for the
conveyance of earth from a hill outside the
fortifications to the fort under construction.
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2022
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3. • An endless rope, attached to which was a number of small
buckets, ran between the two terminal points and was
supported by intermediate standards. The buckets were
filled at the hill and travelled on one side to the fort,
where they were emptied and returned on the other side
back to the hill. The rope ran round pulleys at both
terminals and was driven by hand
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4.  Definition: An aerial ropeway is defined as a transport
system in which transit material is carried in purpose
made cars suspended from over head ropes.
 Advantages:
• It can negotiate steep gradients upto 1 in 2 as there is
independence of adhesion between rail and wheel.
• It can have shortest routes. In other transport systems,
such luxury may not be possible because of terrain
difficulties.
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5. • It has an ability to cross the land used by the owner for
other purpose.
• It can work in fog, rain etc. without any difficulty.
• The power cost is estimated to be the least than any other
alternative system for handling equivalent quantities on
the same route.
• It can negotiate adverse terrain like mountainous regions,
dense forests etc.
• Automation is easy.
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6.  Disadvantages:
• Difficult for supervision in case the infrastructural facilities
are located in remote areas.
• Degradation of mineral takes place if the requirement is
that of the coarse and impurities may get attached to the
mineral fragments.
• Generation of dust can also be a menace.
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7. Classification and Parts of aerial ropeways
In general the ropeways can be classified as:
• Monocable aerial ropeways
• Bicable ropeways
The parts of ropeway:
Wire rope (s)
Trestles
Loading and unloading stations
Angle stations
Buckets
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8. The Monocable aerial ropeway
The monocable aerial ropeway employs a single endless
wire rope for both supporting and transporting loaded and
unloaded buckets.
Each bucket is suspended by a hanger from a box head
equipped with two clips at 430 mm centres from driving
contact with the rope.
Two 200 mm diameter wheels mounted on the box head are
used for traversing on the rails.
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9. Bucket and Hanger on a Monocable Aerial Ropeway
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10. Salient Features of Monocable Aerial Ropeway
• It is used for relatively small capacities
• Lower capital cost as compared to Bicable aerial
ropeway.
• The ropeway is not used on a gradient in excess of 1
in 5 because the box head clips cannot provide
adequate driving force.
Note: Capital cost of ropeway depends upon weight of
individual buckets as the rope strength is controlled
by the same. It has been observed that the reduction
in the loading time can increase the capacity
substantially without requiring increase in the rope
speed and bucket capacity.
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11. Wire Rope (s)
 Ropes for monocable ropeways
• The rope supports both the buckets (track) and carries
them in the required direction (haulage).
• The selection of the rope is governed by:
 Bending stress: It is induced in the rope by the mass of
the bucket. The mass depends upon the ropeway
capacity and its speed.
 Tension: It is developed because of ropeway capacity
and the route profile.
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12. The approximate tension will vary from 30 kN to 100 kN.
Round strand ropes of size 6 × 7 are used.
The factor of safety is normally 5.
In general the diameter of the ropes is either 16 mm or 32
mm.
The diameter of the sheaves is 100 to 120 times the
diameter of the rope to avoid the bending stress.
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13. The Bicable aerial ropeway
• The bicable aerial ropeway employs two separate track
ropes with which buckets are suspended. There is an
endless haulage rope.
• Each of the track rope is anchored at one end and
tensioned at other end.
• The haulage rope is of flexible construction. A 6 × 7 Lang’s
lay rope with fibre core can be used as haulage rope.
• Spliced rope can be used as haulage rope.
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14.  Ropes for bicable ropeways
• It has two ropes one is track and other one is a haulage
rope.
• The track rope is a locked coil rope.
The tension in the rope is 60 to 70 × the individual
wheel load.
Wheel load is the mass of loaded bucket divided by the
number of wheels. Usually the number is 2 or 4.
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15. • The track rope is a triangular strand or round strand rope.
• The determination of haulage rope diameter depends
upon the capacity of the ropeway.
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17. Trestles
• They are usually fabricated from steel sections.
• The trestles are 6 to 10 m high.
• The maximum height of a trestle depends maximum sag.
• It is advantageous to have a trestle as low as practicable.
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18. Monocable Trestles
• The top arms support 350 – 700 mm diameter rope
carrying sheaves.
• The sheaves are so placed at a distance of 450 – 900 mm
centre to centre.
• The figure shows the trestles used in Monocable aerial
ropeways
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20. Trestles for Bicable Aerial Ropeways
• They do not need sheaves fixed to the trestles fitted to
the upper works.
• In the upper part the telephone and signal wires are
attached.
• Flying stays are provided for the rollers over which the
rope can slide.
• The trestles are used on both sides of a bridge which is
used when the aerial ropeway crosses a road.
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22. Angle Stations
• When the direction of the aerial ropeway is to be
changed, the same has to be done at the terminal station.
• Sometimes we have to install angle stations for the
purpose.
• Pulleys are mounted on vertical shafts.
• The vertical and horizontal deflection is achieved by
suitably arranging the rope to pass over the pulleys.
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23. Angle Station
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24. Loading Station
• It consists of structure made up of steel.
• It supports the return sheave for the rope.
• The buckets get disengaged from the rope and run on the
rail.
• The power for the movement is either by manual means
(now obsolete) or by a chain haulage.
• When the bucket arrives at the selected feeder, it is
placed on a weighment bridge.
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25. • The feeder loads a pre-set quantity in the bucket.
• After loading, the bucket is pulled by the haulage.
• The bucket later on catches on the rail.
• For high capacity, a rotary loader is used. The loader
ensures continuous loading without any interruption.
• For small capacity, a hopper and chute arrangement is
used.
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26. Loading Station
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27. Rotary Loading System
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28. Carriers/Buckets
• Three types of buckets are used
 Simple rotating buckets.
Bottom discharge buckets.
Totally enclosed buckets.
• Simple rotating buckets: The bucket is locked in position
by a simple catch gear. The catch is released at the
unloading station. The bucket overturns its content and
returns to the loading station in inverted position. They
are unsuitable for the transportation of sticky materials.
Used on Monocable ropeway.
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29. • Bottom discharge buckets
They are widely used on bicable aerial ropeways. Suitable
for the transportation of wet and sticky material. At
discharge end the bottom door is opened and the material
is discharged cleanly. The lids close automatically due to
their weight.
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30. Bottom Discharge Bucket
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31. • Totally enclosed buckets
These buckets are used when
 When minerals reactive towards water are to be
transported e.g. pyritic ores.
 Very fine materials are to be transported.
The buckets are bottom discharge type
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32. The Drive Terminal
• The drive terminal incorporates a discharge arrangements
before the terminal.
• The drive arrangement consists of an arrangement similar
to that of the endless haulage.
• The wheel has a brake path.
• Thruster brakes are provided to apply the brakes in case
the motor rotates in opposite direction.
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33. Drive Arrangement
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34. Drive Arrangement
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35. Discharge Stations
• There are basically three methods for consideration:
 Depositing between trestles:
The trestles are 30-40 m high and are spaced at 90-100
m. Means are provided for the tipping the buckets. The
material is deposited at its normal angle of repose
along a convenient width. The disadvantage is that the
trestles progressively get buried.
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36.  Tipping by means of a self advancing station:
The buckets leave the ropeway. They travel on a
rail arranged at right angles. The buckets move along a
rail by a chain haulage system. The tipping can be
arranged at any point along the rail. The entire station
is mounted on a caterpillar. After the station has
advanced a distance of 100 m; a new set of trestles is
installed. The height of the muckpile that is obtained is
6-9 m.
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37. Self Advancing Station
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38. Extending frame ropeway:
The system has the least cost amongst the all the three
methods. The bucket coming from the ropeway
discharges its content while passing round a sheave. The
normal climbing angle is 200 . The last
Tresle is lost as loading trestle.
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39. ARERIAL ROPEWAYS CALCULATIONS
• Monocable aerial ropeway
a) Static friction : 1.5 kW to 4 kW
b) Effort to raise to load: CD/400 kW
c) Line friction: CL/20000 kW
d) Gearing losses: 80%
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40. ARERIAL ROPEWAYS CALCULATIONS (Contd.)
• Bicable aerial ropeway
a) Static friction : 1.5 kW to 4 kW
b) Effort to raise to load: CD/300 kW
c) Line friction: CL/13000 kW
d) Gearing losses: 80%
• Where ‘C’ is ropeway capacity, teph
• ‘L’ is the total line length, m
• ‘D’ is the level difference between the loading and
unloading station, m
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41. For transporting uphill
Power = 1.2 (a + b + c)
For transporting downhill
Power = 0.8 (a - b + c)
• Rope sag = w × S2/(0.7 × T)
• Load sag = W × S/(0.4 × T )
• Distributed sag = R × S2/(0.7 × T)
Where S is the horizontal distance between the trestles; T
is the rope tension (N); w is rope weight (kg/m); W is the
weight of loaded bucket (kg); R is the Bucket weight rate =
loaded mass of the bucket/ bucket spacing
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42. • An aerial ropeway transports the mineral over a length of
6700 m. The delivery point is 58 m above the loading
point. The ropeway capacity is 450 te/h and the speed is
245 m/min. The bucket capacity can be assumed to be
1650 kg.
Solution =
The bucket/h = 450/1.65 = 272.73
Allowable time per bucket = 3600/272.73 = 13.2 s
Rope speed = 245 m/min = 4.08 m/s
Load spacing = 4.08 × 13.2 = 53.9 m
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43. • Number of full buckets = 6700 / 53.9 = 125 (say)
• Power = 1.2 (4 + 87 + 232) = 1.2 (293) = 352 kW
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