A PROJECT ON MECHANISED LONGWALL
Transcript of A PROJECT ON MECHANISED LONGWALL
ISSN NO: 0745-6999
JOURNAL OF RESOURCE MANAGEMENT AND TECHNOLOGY
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A PROJECT ON MECHANISED LONGWALL 1PALETI SREENIVASA RAO,2 Dr. T. DHARMARAJU, 3Mr. K.S. RAMBABU
1M.Tech Student, 2Professor, 3Assistant Professor
Department Of Mechanical Engineering(MINING)
KAKINADA INSTITUTE OF TECHNOLOGICAL SCIENCES, Ramachandrapuram
ABSTRACT
The primary effect of long wall mining is
dependent on the level of automation and the
availability of supports.
Double ended range drums are used in coal
extraction, with extraction occurring in a single
direction.
Power pack and all ancillary equipment, such as
AFC, BSL lump breaker, and shock shields, are
employed in the face mechanisation process,
which is completed by the advancement of
shock shields at the end of the process. The
AFC advances at the same time, as does the
power pack, which is located in the main gate
and has a length of 150m by extraction of the
face, which is done by the retreating technique.
The salvage phase is defined as the time period
during which a machine is utilised to move
employees from one location of employment to
another.
INTRODUCTION
Longwall:-
Mining using a longwall is a technique that
involves driving two parallel gate road ways at
predetermined intervals and joining the two
gate road ways at the conclusion of the mining
process. Longwall face is the term used to
describe the process of installing long wall
equipment in a linked gallery.
Longwall in India
• It was in Moonidih, CIL, in August
1978 that the world's first automated
powered support longwall caving face
was installed.
• GDK.7 Incline was the first longwall
face to be installed in SCCL, which
happened in September 1983.
• Due to a variety of factors, there has
been little progress in India in the field
of longwall technology.
Longwall mining in SCCL
• Longwall mining was deployed for the
first time in SCCL in the year 1983 at
the GDK-7 Incline, and after the
successful completion of two faces, the
equipment was transferred to the GDK-
9 Incline in 1986, where the Longwall
face collapsed owing to insufficiency
of the support capacity.
• Longwall packages were added to VK-
7 and JK-5 Inclines in 1985 and 1990,
respectively, to accommodate the
growth of the industry.
• Following that, three more Longwall
packages were launched in GDK-11A
over the years 1992-1993. The
motorised roof supports in the
aforementioned mines have a capacity
of 4x360 tonnes (t) and 4x450 tonnes
(t).
• Later, higher-rated supports were
added, with one set in each of the
GDK-10A and GDK-9 Inclines and
two sets in the PVK 5 Incline.
• The support capacity in the
aforementioned mines is 4x800t and
4x760t, with a support density of 110
to 120 t/m2 and 110 to 120 t/m2 in the
mines above, respectively.
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3. TERMINOLOGY USED IN LONG WALL MINING
LONGWALL GENERAL LAYOUT
Long-Wall Terminology
• The face: The front end from which the
coal is won.
• Tail Gate: The roadway usually used for
the supplies of material and return air. It
is also known as Supply Gate.
• Main Gate: The roadway used for
transport of coal out bye and for the
intake of air, it. Is also known as Mother
Gate.
• Goaf Line: The line at which roof is
intended to cave.
• Span: the width of the working from the
goaf line supports to the face.
• Stable: the extended portions of gated
roadways beyond the wall face.
Prepare to accommodate the
machine to cut the face.
Stables are usually 8 to 10
meters.
• Buttock: the portion of the face at its end
from where cutting starts.
• Face Conveyor: the conveyor installed
on the on face.
• Stage Loader: The conveyor which
receives coal from the face conveyor for
its transport out-bye.
• Face Supports: the supports used on the
face.
• Breaking row supports: the supports at
the goaf edges.
• Pack wall: This is constructed in the long
wall advancing method to isolate the goaf
and the face
• .
Direction of retreat
FACE
Bottom Gate
TOP
Dip directio
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3. DIFFERENTLONGWALLMINING
1. Long wall Advancing Method 2. Longwall Retreating Method
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Applicability of Long Wall Mining
Method:
1. The seam may be as small as 0.7 metres
thick or as thick as 5.5 metres thick, with a
maximum thickness of 6 metres.
2. Alternatively, seams with a taught
ceiling will bend gradually and settle on
packs, while seams with a friable roof may
collapse in the goaf.
3. In order to extract continuous seams, it is
necessary to lay down solid packed faces
with little disruption.
4. With regard to gaseous seams, which
need careful ventilation planning
5. Seams reinforced with mud bands
6. Seams that will be automated in order to
produce a big volume
7. Seams that are uniformly thick
8. The use of the pillar and stall technique
may be problematic in deep seams larger
than 500mts because of the high strain on
the pillars.
9. Coal with a medium hardness rating
10. Seams that have seen less geological
disruption
11. Mining with several seams
12. Seams that are located at considerable
depth
13. Seams that are close together
Merits of Long Wall Mining:-
1. It is straightforward, allows for
concentration of work areas, and is capable
of producing the highest possible yields per
hectare of coal seam.
2. It allows for effective monitoring.
3. The seam segment is removed in a single
operation in order to achieve the highest
possible extraction percentage.
4. Workplace ventilation may be readily
decreased by using simple and direct
methods.
Roof weight pressing on face causes coal to
become looser, resulting in the highest
percentage of big coal being produced.
Cleats and stairs in coal may be utilised to
advantage in order to make winning more
straightforward. Coal that is friable and
weak may also be readily won.
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6. Dirt bands in the seam may be used to
stuff goofballs in a pinch.
7. Because there are just a few road ways to
maintain, the floor is less susceptible to
creep.
8. This technique is capable of working
well on seams that are prone to splitting.
All coal that has the potential to be used for
heating is removed 9. This results in
mechanisation at the lowest possible capital
cost per tonne of yearly production.
10. Provide the most successful complete
technique for operating under another sea
that has been thoroughly tested.
11. The protection of human resources
12. Fast rate and face advance are two of
the most popular options.
Demerits of Long Wall Method:-
1. Equipment is costlier
2. More maintenance cost
3. Danger of fire, spontaneous heating, &
fire damp in long wall advancing with
caving system
4. Leakage of air current in gob working
by long wall advancing with caving
4. MACHINERY EMPLOYED IN
LONGWALL MINING
Shearers:
• Shearer are one of the most
popular cutter loaders for use
in the long wall faces
• may be fixed or mounted on
ranging arms
• There are four types of
shearers are there and they are
• Single ended fixed drum
shearer • Single ended ranging drum
shearer
• Single ended double ranging
drum shearer
• Double ended ranging drum
shearer
SINGLE ENDED RANGING DRUM:
The cutting drum of the shearer is mounted at
the rear end of the ranging arm.the ranging arm
can be raised up and down by hydraulkic
control to accommodate the changing seam
thickness and floor undulation. In SERD there
is only one cutting drum at front side
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Cutting and raising of the shearer drum
Double ended ranging drum shearer:-
Nowadays, the double ended
ranging drum shearer is the most often seen. The
shearer completes the whole seam height in a
single pass. They may be moved to any desired
height throughout the cutting process and
dropped far below the level of the cutting table
itself. With the drums configured in this manner,
the whole seam may be cut in either direction of
travel, resulting in fast face advancement and a
shorter roof exposure time. It has the ability to
sum in either way. During the cutting trip, the
leading drum cuts the top 70 percent of the seam
height, while the rear drum cuts the bottom 30
percent of the seam height and cleans up the
broken coal that has fallen to the ground. The
distance between the two drums is about 7-10m.
Main components of shearer
• Electric motors
• Gear head
• Haulage unit (power pack)
• Cutting drum
MODREN SHEARER CUTTING AND LOADING IN LONGWALL
The shearer with a web of 0.65 metres is shown
in this figure as cutting coal in the
contemporary day. The coal is directed by the
arrangement of the cowl. The A.F.C.
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coalisloaded the coal With the hydraulic power
chockshield in place, the face is stabilised.
4 of a total of 560 te capacity.
5. STARTA CONTROLLING IN
LONGWALL
Classification of Powered Supports
• Frame
• Chock
• Shield
• Chock shield
The function of the powered supports
• To maintain a safe and coal-
producing working environment
surrounding the coal face;
• To restrict the amount of roof to floor
convergence;
• To prevent broken rock from entering
the work area; and
• To secure and advance all equipment
on the coal face, including roof
supports..
FRAME TYPE
The frame type is an evolution of the single
hydraulic props that are traditionally employed
in subterranean applications.
The first kind of contemporary self-advancing
hydraulic powered support system was created
in this manner. It consists of mounting modern
self-advancing hydraulic prop or legs vertically
in tandem, which are linked at the top by six
single or two segmented canopies.
Chock support
In a chock support the canopy is a solid piece
and the base may be either a solid piece or two
separate parts connected by steel bars the rear
and the front end.The hydraulic legs are
installed vertically between the base and the
canopy.the number of legs ranges from 3 to
6,but the 4 legs chocks are by farthe most
popular ones
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Chock Shield Supports
• In this all legs connected between the
base and roof canopy
• Base and top canopy also connected at
the rear by a strong caving shield and
lemniscates linkage
• Usually provided with side shield and
fore-pole arrangement on the top
canopy and also in some verities face
sprags are provided
• Support is very much stable
• Have excellent anti-flushing
characteristics
• With stands longitudinal and lateral
forces
• Four legs act directly into the top main
leg canopy
• Yield load is constant throughout the
height range
• Base unit is rigid
• Has no leg mountings
• Lemniscateslinkage ,the back shield to
getherly ensure minimum offset loads
on the legs of the support
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6.SALVAGING OPERATION
Salvaging: - Salvaging is the process of
moving the face machinery or equipments of a
long wall from the worked out panel to the
installation panel.
Salvaging Period refers to the time period
during which such work is carried out.
• The whole operation may be overseen by a
"First class management compedency
certificate holder," who will be in control of the
overall operation. Mine manager
"Madhusudhan sir" and short wall incharge
"Nehru sir" were the ones who took it in the
"RKNT" mine.
Working under the direct supervision of a
second class management certificate holder, as
well as electrical and mechanical engineers on
each shift, the salvage and installation work in
the “RKNT” mine was completed in a timely
manner.
• Salvage operations are carried out by
personnel with a high level of expertise.
Preparatory Works Before Starting
Salvaging Operations:-
Maintenance of the powered supports
including the hydraulic parts is done
before the start of the salvaging
operations.
MESHING IN SALVAGING
OPERATION:-
Meshing:-
Wire meshing is laid on the roof from
11 metres behind the face stop line,
with roof bolts of 1.8 metres in length
and 1 metre between two roof bolts,
and with W-straps for the balance
portion at 1 metre intervals. After the
production has stopped, meshing and
bolting is completed to the face as well
as the rest of the roof.
Procedure of bolting:-
Initial rows of roof bolts are completed
at one end mesh netting before the
power roof support is progressed
further.
When the face progresses 1.5 metres
farther, another row of roof bolts with
mesh is installed, and the process is
repeated up to 2 metres from the stop
line (7dip).
Another row of roof bolts is completed
with a w strap attached to the wire
mesh after this 2 metres of face
progress has been completed.
Purpose of Meshing to the Roof:-
The roof shall be meshed starting from
a distance of 11 meters from the exact stop line
to prevent the flushing of goaf during salvaging
operation.
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7. CONCLUSION
The primary effect of long wall mining is
dependent on the level of automation and the
availability of supports.
Double ended range drums are used in coal
extraction, with extraction occurring in a single
direction.
Power pack and all ancillary equipment, such as
AFC, BSL lump breaker, and shock shields, are
employed in the face mechanisation process,
which is completed by the advancement of
shock shields at the end of the process. The
AFC advances at the same time, as does the
power pack, which is located in the main gate
and has a length of 150m by extraction of the
face, which is done by the retreating technique.
The salvage phase is defined as the time period
during which a machine is utilised to move
employees from one location of employment to
another.
Longwall technique may be implemented more
effectively than other extraction methods, as a
result of which it is preferred.
When it comes to longwall mining, the
salvaging operation is the most difficult job. To
do this, one panel from one panel and following
panel is removed by the longwall advancing,
advancing and retreating is preferred.
The daily output achieved from longwall
mining is much higher than that obtained from
traditional mining techniques. If the seam has
an inclination more than 1 in 3, it is preferable
to face the longwall along the strike in order to
effectively construct it.
Overall, rules have an impact on production. In
certain instances, however, laws restrict certain
activities; in such cases, permits from the chief
inspector, together with appropriate plans based
on the geological conditions, are preferred, and
permission is acquired.
REFERENCES
1. S.PENG and H.S.CHIANG “design
consideration of panel layout, chock shield,
shearer and plough ”
2. TAPAN KUMAR “longwall mining at
shallow depth below 100 to 200 mtrs”
3.AKKERA FUKUNDA “real time estimate
of supports and design of longwall panel in coal
mine”
4.R.D.SINGH “basics of long wall, the forces
acting during extraction, types and laying of
support in longwall”
5. G.D.K 10 INCLINE MINE DETAILS
AND PLANS..
6.WWW.COALEDUCATION.ORG
7.WWW.BRITANNICACOALMINES.Org
8. G.POPOV “The working of mineral
deposits in thin seams by longwall”
9. PELEE.R “machinery employed in longwall
and their details inMining Engineering hand
book”
10. N.T.KARELIN “transportation of coal and
material from longwall panel to surface”