A PROJECT ON MECHANISED LONGWALL

ISSN NO: 0745-6999

JOURNAL OF RESOURCE MANAGEMENT AND TECHNOLOGY

Page No:566 www.jrmat.com Vol 12, Issue4, 2021

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.

ISSN NO: 0745-6999



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

ISSN NO: 0745-6999



3. DIFFERENTLONGWALLMINING

1. Long wall Advancing Method 2. Longwall Retreating Method

ISSN NO: 0745-6999



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.

ISSN NO: 0745-6999



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

ISSN NO: 0745-6999



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.

ISSN NO: 0745-6999



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

ISSN NO: 0745-6999



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

ISSN NO: 0745-6999



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.

ISSN NO: 0745-6999



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”

Documents

A PROJECT ON MECHANISED LONGWALL