guide for method of working coal

General Mining methods

• Two methods;

• Opencast

• Underground.

• When the cost of Overburden removal to expose the coal is economical, opencast mining is adopted.•

• Technology used in underground mining depends on geology and geometry of the seam.

•Smaller deposits can have Manual loading and intermediate technologies with continuous miners or LHDsand SDLs–Bord and Pillar method.

•Large reserve and uniform deposit are mined by Longwall mining –a bulk production but capital intensive technology.

• Mechanisation in Bord and pillar has limitations of gradients. Seams steeper than 12°(1 in 5 ) are not suitable -leaving little possibility to mechanise most of the mines with these deposits.

Existing technologies

A) TECHNOLOGIES IN OPEN CAST 1)SHOVEL-DUMPER 2)SURFACE MINER 3)DRAGLINE 4)HIGH WALL MINING

B) TECHNOLOGIES IN UNDERGROUND 1) MANUAL 2) SEMI MECHANISATION

i)SDLs ii)LHDs iii)CONTINUOUS MINER

3) LONGWALL MECHANIZATION : Shearer, etc.

UG

METHODS

BP

LW

TECHNOLOGY

INTERMEDIATE

MASS PROD

EQUIPMENT

UG OPERATIONS

DRILLING

BLASTING

CUTTING

SUPPORT

HAULING/

TRANSPORT

TARNSFER

VENTILATION

PUMPING

LIGHTING

UG MINING EQUIPMENT

DRILLING /BLASTING CUTTING

COAL CUTTING MC

SHEARER

CONTINUOUS MINER

ROAD HEADER

BORER

LOADING

SDL

LHD

GAL

ROOF SUPPORT VENTILATION TRANSPORT /HANDLING

COAL

HAULAGE

ENDLESS

DIRECT

CONVEYOR

BELT

CHAIN (AFC)

WINDING

DRUM

FRICTION

MATERIAL MAN

WINDING

MAN RIDING

CAR

SAFETY & RESCUE

UNDERGROUND MECHANISATION STATUS (Feb’11)

EQUIPMENT ECL BCCL CCL WCL SECL MCL CIL

SDL 161 147 19 73 211 21 632

LHD 38 3 6 116 148 30 341

ROAD HEADER 2 4 6

PSLW 1 3 3 7

SHW 1 1

CONT MINER 2 2 2 6

UNDERGROUND MECHANISATION PRODUCTION STATUS (2009-10)

EQUIPMENT ECL BCCL CCL WCL SECL MCL CIL SDL 3.08 2.79 0.23 2.86 9.81 0.47 19.24 LHD 1.02 0.05 0.16 5.94 6.75 4.67 18.59

ROAD HEADER 0.01 0.05 0.06 CONT MINER 0.46 0.17 0.48 1.11 SHW 0.33 0.33 PSLW 0.03 0.16 0.03 0.22

CONV MECH LW 0.03 0.03 MECHANISED 4.59 3.08 0.40 8.96 17.39 2.14 36.56 MANUAL 3.64 0.82 1.07 0.66 0.44 0.06 6.69

TOTAL UG 8.23 3.90 1.47 9.62 17.83 2.20 43.25

TECHNICAL CONSIDERATIONS

Based on gradient of the seam :

Manual : In all grdients

SDL : Where the gradient is <= 1 in 5 (120)

LHD : Where the gradient is <= 1 in 6 (100)

Continuous Miner : Where the gradient is <= 1 in 8 (70)

Longwall : Where the property is devoid of fault.

Board and pillar

• In Board-and-pillar mining, coal deposits are mined by cutting a network of ‘roads’ into the coal seam and leaving behind ‘pillars’ of coal to support the roof of the mine. These pillars can be up to 40% of the total coal in the seam – although this coal can sometimes be recovered at a later stage. This can be achieved in what is known as ‘retreat mining’, where coal is mined from the pillars as workers retreat. The roof is then allowed to collapse and the mine is abandoned.

Board and pillar

• The main advantage of Board–and-pillar

• mining over longwall mining is that it allows coal production to start much more quickly, with less costs.

Board

Board

Road

The 10 feet (3m) wide tunnel leading from the midpoint along each coal face to the underground roadway was called the Mothergate. Coal from the face conveyors dropped onto the Mothergate conveyor, which carried it back to the roadway. At the roadway, the coal was loaded into tubs for the journey to the shaft Listen to Jim Slaughter talking about Mothergate.

As the coal was dug out and the face advanced, the space left behind it was filled with waste stone from the Mothergate and barriers. There was not enough waste stone to prop up the unsupported roof, which had once rested on coal. When the weight of stone above became too great, due to the extraction of coal, a rock fall would occur, bringing down the stone onto the goaf. Once this had happened at a face, it would continue to happen every day as the face advanced.

This is where the face would have been yesterday. Every day, coal is dug out all along the face, exposing a new face for the next day. Each night, the Mothergate and barriers are advanced forward to the new face.

A 6 feet (1.8m) wide service tunnel, called a barrier, led from the underground roadway to each end of a 200 feet (60m) long coalface. These arrows shows the direction travelled by tools, pit props and other materials needed at the face. Pit ponies, pulling wagons along rails, transported these items to the end of the barrier. At the face, materials were loaded onto the face conveyer and carried along the face to where they were needed.

http://www.pastperfect.info/sites/woodhorn/audio/clip22.html

http://www.pastperfect.info/sites/woodhorn/audio/clip22.html

• For DEVELOPMENT & EXTRACTION

• Continuous miner* - 1 no.

• Shuttle cars - 2 no.

• Twin/ Quad bolter* - 1 no.

• Feeder breaker - 1 no.

• Power pack - 1 no.

• Mobile goaf edge support (Optional) -2 nos.

• (* In some package both the machines are integrated into one)

CONTINUOUS MINER package

• For EXTRACTION

• Shearer - 1

• Powered support - 1 set

• Armoured Face Conveyor - 1

• Stage loader - crusher - 1

• Power pack - 1

• For DEVELOPMENT

• Continuous miner package or

• Roadheader package

POWER SUPPORT LONGWALL package

24

Longwall • Longwall mining involves the full extraction of coal from a

section of the seam or ‘face’ using mechanical shearers to cut and remove the coal at the face, which can vary in length from 100-350 m. .

• A longwall face requires careful planning to ensure favourable geology exists throughout the section before development work begins.

• The coal ‘face’ can vary in length from 100-350m. • Self advancing Roof Supports (SARS) are used( hydraulically-

powered supports) to temporarily hold up the roof while coal is extracted.

• When coal has been extracted from the area, the roof is allowed to collapse.

• Over 75% of the coal in the deposit can be extracted from panels of coal that can extend 3km through the coal seam.

LONGWALL MECHANISATION

• Shearer

• SARS

• AFC

• Stage loader

• Gate belt

• Trunk belt

• Other belts

Self advancing support system

• 2 to 6 hydraulic props (legs) fixed to a common base plate. • A heavy roof canopy (plate) mounted over the legs for setting against the roof. • A double acting horizontal hydraulic ram linked to the face conveyor for shifting

the face conveyor and for pulling the support towards the face. • A rear guard shield for preventing the flow of debris into the face. • A power pack to provide the high pressure fluids through hoses as the power

medium for moving the support.

• The Self-Advancing Roof Supports (SARS) perform the additional functions: • — Protection of workers and the machines at coal faces. • — Shift the coal face equipment with the help of hydraulic rams. • — Provide immediate continuous support to the exposed roof. • — Provide high rate of face advance in conjunction with coal cutting machines like

shearer/plough.

Sl.No. PROJECT Capacity Rated (TPD)

ECL

1 Jhanjra 1&2 Inc. 1476

2 Jhanjra 1&2 Inc. 3000

3 Jhanjra-MIC 1476

BCCL

4 ML-IV 860

5 ML-V 840

6 ML-VI 470

7 ML-VII 3200

SECL

8 Balarampur 1950

9 New Kumuda 1950

10 Rajendra 2300

SCCL

11 VK-7 Inc 1600

12 JK-5 Inc 2000

13 GDK-10A Inc 2200

14 GDK-9 Inc 1900

15 PVK Inc 2200

STATUS & PRODUCTION OF INDIAN LONGWALL MINING

Continuous miner

http://www.mining-technology.com/contractors/project/kopex/

SIDE DISCHARGE LOADER (SDL)

LOAD HAUL DUMPER (LHD)

ROAD HEADER

CONTINUOUS MINER

SHUTTLE CAR

ROOF BOLTER

SHEARER

POWERED SUPPORT

POWERED SUPPORT LONGWALL

UG OPERATIONS

DRILLING

BLASTING

CUTTING

SUPPORT

HAULING/

TRANSPORT

TARNSFER

VENTILATION

PUMPING

LIGHTING

Product Range

Shearers

Roof Supports

Continuous Miners

A.F.C’s

Articulated Haulage

Shuttle Cars

Continuous Haulage

Flexible Conveyor

Train

UG MINING EQUIPMENT

DRILLING /BLASTING CUTTING

COAL CUTTING MC

SHEARER

CONTINUOUS MINER

ROAD HEADER

BORER

LOADING

SDL

LHD

GAL

ROOF SUPPORT VENTILATION TRANSPORT /HANDLING

COAL

HAULAGE

ENDLESS

DIRECT

CONVEYOR

BELT

CHAIN (AFC)

WINDING

DRUM

FRICTION

MATERIAL MAN

WINDING

MAN RIDING

CAR

SAFETY & RESCUE

UG MINING METHODS

• Coal deposits are mined by cutting a network of ‘roads’ into the coal seam and leaving behind ‘pillars’ of coal to support the roof of the mine.

BORD & PILLAR Method

• It involves the full extraction of coal from a section of the seam or ‘face’ using mechanical shearers to cut and remove the coal at the face.

• Self advancing Roof Supports are used to temporarily hold up the roof while coal is extracted.

LONGWALL Method

59

• DRILLING MACHINES (Hand held, Tyre/ crawler mounted)

• ROAD HEADER

• SHEARER

• CONTINUOUS MINER

• SIDE DISCHARGE LOADER(SDL)

• LOAD HAUL DUMPER(LHD)

WINNING & LOADING

• CONVEYORS (Belt conveyors, Chain conveyors)

• HAULAGES (Direct haulage, Endless haulage, Main & tail haulage)

• WINDING SYSTEMS (Drum winder, Friction/koepe winder)

• MAN RIDING SYSTEMS

• SHUTTLE/RAM CARS

• LOCOS

TRANSPORTATION

60

MAJOR UG EQUIPMENTS

VENTILATION FANS

PUMPS

• Self contained self rescuers

• Gas monitoring devices

SAFETY RELATED EQUIPMENTS

SHOT FIRING EQUIPMENT

• Shield type hydraulic power support

• Individual hydraulic/friction/screw supports

SUPPORTS

61

Support UG Equipments

MONITORING DEVICES

• Hand held

• Crawler mounted

ROOF BOLTER

• Conventional wire based

• From surface to UG- wireless and from UG to surface – Combination of wire and microwave

COMMUNICATION SYSTEMS

62

Support UG Equipments

•Continuous Miner

•Highwall Mining

•Powered Support Longwall

UNDERGROUND

•Surface Miner

•Continuous Miner

OPENCAST

63

MASS PRODUCTION TECHNOLOGY

U/G MECHANISATION IN CIL (February 2011) Comp. SDL LHD High

Cap LHD

Road Header

PSLW SHW Cont. Miner

ECL 161 38 - 2 1 - 2

BCCL 147 3 - 4 3 - -

CCL 19 6 - - - - -

NCL - - - - - - -

WCL 73 116 - - - - 2

SECL 211 140 8 - 3 1 2

MCL 21 30 - - - - -

CIL 632 313 8 6 7 1 6 64

Calculation of deformation (longwall / face roadways)

Long-term stability

(shaft / pit bottom)

Effects of mining (subsidence / stress

redistributions)

Support design

Depth > 1000 m (3281 ft)

Multiple seam mining

Several planning tools

TECHNOLOGY ADOPTION IN UNDERGROUND MINES

In CIL intermediate technology has been introduced for major operations

like coal winning by drilling and blasting with use of explosives, roof

supports by bolting etc. and coal loading with SDL/LHD.

SDL LHD

TECHNOLOGICAL OPTION IN UNDERGROUND MINES

SDL LHD

MINING WITH BLASTING AT FACES

Conventional Bord and Pillar with Side Discharge Loader(SDL)/ Load Haul

Dump (LHD) m/c.

Bord and Pillar with SDL/LHD & Universal Drill Machine (UDM)

Cable Bolting method with Remote SDL/LHD

Blasting gallery Method of Mining

BLASTING FREE MINING

Long Wall Mining. Short wall Mining. MPT with Continuous Miner & Shuttle Car Combination. Low capacity Continuous Miner (LCCM) High Wall Mining

Continuous Miner (CM) & Flexible Conveyor Train (FCT) Combination.

SDL LHD

Conventional Bord & Pillar with SDL/LHD.

Both development and final extraction of coal property by SDL/LHD is

a very commonly practiced mining methodology today in B&P layout.

However, hike in wages cost and quantum jump in coal demand now

necessitates search for suitable technological option.


SDL LHD


Bord and Pillar with SDL/LHD & Universal Drill Machine (UDM).

UDMs have been introduced for coal face and roof drilling in several

mines with following advantages:

Faster rate of drilling both in coal face and roof.

Faster and better coal preparation.

Optimization in manpower.

Enhanced safety status due to elimination of manual drilling.

Higher production and productivity.

SDL LHD


Cable Bolting method with Remote SDL/LHD in Bord & Pillar layout.

Useful for extraction of moderately thick seams and support of high

roof is by cable bolts.

Practiced successfully in some mines of ECL and SECL using Remote

Controlled SDL/LHD.

SDL LHD


Blasting Gallery Method of Mining.

successfully introduced in SCCL, ECL

and SECL for moderately thick coal

seams

(6-8 m)

Major equipment in use :

- Remote controlled LHDs

- Jumbo Drill machine.

- MDCC

- Lump Breaker.

- 40T Individual Props.

BARRIER

BARRIER

BARRIER

Step 6

SDL LHD


Long Wall Mining.

PSLW technology experimented in the country at:

• Dhemo Main, Seetalpur, Jhanjra (ECL)

• Patharkhera (WCL)

• Moonidih (BCCL)

• Church, New Kumda, Balrampur, Rajendra (SECL)

• GDK , PVK Mine etc (SCCL)

This technology has yielded mixed results in terms of output and

economics due to problems in strata management in case of hard and

massive overlying strata, equipment support and back-up services,

inadequate geological investigations etc.

SDL LHD


Short wall Mining.

Envisages extraction of standing coal pillars developed in Bord &

Pillar layout with the help of PSLW equipment.

The developed galleries are suitably supported in advance.

Short wall mining was commissioned at a UG mine in SECL in

December’07.

Six panels were successfully extracted giving an average production

of 1200-1400 TPD.

Powered supports of 4 x 650 Te. capacity at the face.

SDL LHD


Mass Production Technology (MPT) with Continuous Miner (CM) &

Shuttle Car.

Introduced at a number of mines in the country since the year 2002 in

WCL, SECL, SCCL and ECL.

Suited to the Indian conditions. It is versatile, flexible and less capital

intensive.

percentage of coal extraction in a panel is significantly higher (around

75-80%). Coal production to the tune of 0.60 Mty has been achieved

from a CM package in the country.

A higher production level is possible with moderate seam thickness.

SDL LHD


Low Capacity Continuous Miner (LCCM).

A scaled down version of the Continuous Miner package.

This equipment has experimentally been introduced in some coal mines

and average coal output is anticipated to be at a level of 600 TPD from

both development/ depillaring in Bord and Pillar mining with 2.2m to

2.4m thick coal seam.

Such equipment may find wider application considering relatively low

capital investment and the advantages.

Further steps ahead shall be taken towards equipment design/capacity

improvement after review based on operational experiences.

SDL LHD

RECENT TECHNOLOGICAL OPTIONS.

High Wall Mining.

This is a new technology and planned to be operational shortly in the country.

• Suitable for thin and moderate coal seams and seams not possible to be

exploited economically by any available UG or OC method now and where the

coal reserves are liable to be lost or sterilized.

Well suited under the following geo-mining environment:

I) At quarriable limit where highwall position reached.

II) Where coal has become sterilized due to surface constraints.

Coal seam is approached through a trench. Exposed coal on either side of the

trench is extracted by remotely operated Continuous Miner leaving adequate

remnants between two consecutive webs where the overlying strata remain

unaffected.

SDL LHD

TECHNOLOGICAL ADVANCEMENT ON THE HORIZON

1.Continuous Miner (CM) & Flexible Conveyor Train (FCT) Combination.

• The technology is operating in some mines in UK and USA.

• The requirement of Shuttle Car is dispensed with and is replaced by Tyre

mounted flexible conveyor which can be articulated as per requirement

during mining operations in a panel.

• The flexible conveyor is linked to the out bye end of the Continuous Miner

and discharges coal on the gate belt. The length of the FCT varies between

70m to 130m.

• Due to greater continuity in mining cycle, productivity is enhanced by

around 50% to 60% compared to Continuous Miner and Shuttle Car

combination.

“ UNIQUE EXPERIENCE ON SHORTWALL

MINING IN INDIAN COAL MINING

INDUSTRY”

M.P. Dikshit

Chairman-cum Managing Director South Eastern Coalfields Limited

SHORTWALL MINING AT BALRAMPUR MINE, BISHRAMPUR

AREA, SECL

110

FACE RETREATING

GOAF

B A R R I E R

P I L L A R S

PANEL LENGTH = 540M

INTRODUCTION

• The Shortwall technology for extraction of developed

bord & pillar property.

• PSLW with associated equipment.

• Implemented at Balrampur Mine in CIC.

SHORTWALL MINING

Shortwall Mining - an evolutionary variation of L/W

mining for extraction of developed B&P workings.

Geometric simplicity (Shorter face length : 84m/104m)

Effective strata control by Powered Supports.

Face optimum obliquity = 9-110 to limit exposure at a time.

Roof Supports: Powered Support + OC Props and cable

bolting at developed galleries/gate roads for better strata

management.

SCOPE OF SHORTWALL TECHNOLOGY

• In India around 3000 MT Coal is locked in developed

pillars in different geomining environment.

• Encouraging results in operation, productivity, safety,

conservation of coal & strata management during

operation.

• To avoid crushing/spalling of sides, ventilation

constraints, spontaneous heating, locking of other

prospective seams besides inconvenience for longer

maintenance of these standing coal pillars.

SALIENT INFORMATION OF SHORTWALL PANELS

Sl

No

Parameters Panels already worked

63L 58L 57L

01 Depth of Cover (M) 40-51 34-42 34-37

02 Panel Length (M) 540 460 530

03 Working Seam Height

(M)

2.5

04 Face Length (C-C) (M) 80

05 Face Orientation 90 – 110

06 Pillar Size (C to C) 20m X 20m

07 Width of the Gallery 4 to 4.5m

08 Seam Gradient 1 in 51

09 Location of Main Gate

Top

Top Bottom

10 Period of Operation 30.12.07 to

28.03.08

25.4.08 to

25.7.08

19.8.08 to

12.11.08

Sl

no

Parameters Panels already worked out

34L S-7 S-6

01 Depth of the Cover

(M)

30-34 32 30

02 Panel Length (M) 380 440 440

03 Seam Thickness 2.5m

04 Face Length (m) 100 80

05 Face Orientation 90 - 110

06 Pillar Size (C to C) 20m X 20m

07 Width of the

Gallery

4 to 4.5m

08 Gradient 1 in 51

09 Location of Main

Gate

Bottom Top Top

10 Period of Operation 11.12.08

to

15.02.09

20.03.09 to

30.06.09

25.07.09 to

05.11.09

PHYSICO MECHANICAL PROPERTIES OF COAL

Density

(kg/m3)

Compressive

Strength

(MPa)

Tensile

Strength

(MPa)

Modulus of

Elasticity

(GPa)

1400 27.9 3.11 1.8 PHYSICO MECHANICAL PROPERTIES OF FLOOR ROCK

Roc

k

Typ

e

Densit

y

(Kg/m3

)

Compressi

ve

Strength

σ c

(MPa)

Tensile

Strengt

h

σ t

(MPa)

Modulus

of

Elasticity

,

E

(GPa)

RM

R

Sand

Ston

e

2243 14.5 2.2 3.0 65

PHYSICO MECHANICAL PROPERTIES OF ROOF

ROCK ( From immediate roof & upwards)

Rock

Type

Thick-

ness

(M)

Density

(kg/m3)

RQD

(%)

σ c

(MPa)

σ t

(MPa

)

E

(GP

a)

RM

R

Mg. Sst.

with

laminatio

ns

5.5 2267 40 11 1.5 1.8 55

Cg.-Mg.

Sst.

6.7 2250 78 17.1 1.4 3.0 65

VCg. Sst. 3.9 2250 43 13.9 1.4 2.0 55

Mg. Sst. 14.0 2243 75 14.5 2.2 3.0 70

Weathere

d rock

11.0 2138 40 14.5 2.2 0.3 42

Weathere

d rock &

soil

9.0 2000 - 8.0 0.08 0.3 -

SHORTWALL EQUIPMENT

EQUIPMEN

T

Powered Supports

Armoured Face Conveyor

Shearer

Bridge Stage Loader & Crusher

Power Pack & Communication

System(Ck2), Electricals

POWERED SUPPORTS

Canopy

Leg

Back Shield

Base

3.62 m

2.14 m

1.4-2.7m

Lemniscates linkage

POWERED SUPPORTS-TECHNICAL FEATURE

Type of Support 4 Leg Chock Shied

Height 1.4- 2.7m

Canopy Length 3.62m

Width 1.5m

Support Density 116 Te/m 2 (min.span)

100 Te/m2 (max.span)

Setting Pressure 30MPa

Yield Pressure 41MPa

Capacity 650 Te.

Operation Mode Adjacent Control

Weight 16.13 Te.

Leg Stroke 679 mm

SHEARER

TECHNICAL FEATURES

Coal Seam

Cutting Height 1.5 – 3.1 m Inclination <= 35˚ Coal Hardness Medium to Hard

DESCRIPTION OF SHEARER

Drum Diameter : 1600mm

Centre dis. of Drum : 8432mm

Web Depth : 600mm

CUTTING SYSTEM

Length of ranging arm : 1681mm

Swivel angle of arm : 17˚ to 50˚

Total picks per drum : 48 nos.

POWER

375 kW / 1100 V

Haulage Speed : 0-6.1m/min

Control system : Electrical & Mechanical

ARMOURED FACE CONVEYOR Description Value

a) Capacity

(Maximum)

800 Te./ hours

b) Chain

Speed

0.92m/second

c) Motor

(Tail and

Drive)

150 kW Tail

and Drive end

at 1.1 KV.

d) Line Pan

Size

1500mmX

764mm X

275mm

e) Chain Size 26 X 92 mm

f) Chain Configuration

2 In-board

BRIDGE STAGE LOADER (B.S.L.)

Make CME, I&E, PR-China

Type SZZ-764/132

Effective overlap 12m

Line Pan Size 1500mmX764mmX222m

m

Chain Configuration 2 In-board

Chain Dimension 26mm X 92mm

Chain Speed (m/Sec) 1.2 m/Sec.

Distance bet. flight (mm): 736mm

Conveying Capacity 900 TPH

Drive Motor 132 KW / 1.1 KV

POWER PACK DESCRIPTION VALUE

A) Nominal Pressure 31.5 MPa

B) Nominal Flow 200 LPM

C) Motor Power 125 kW / 1100 V

D) Water emulsion oil

ratio

95 : 5

E) Emulsion Tank

i) Model R X 1600

ii) Capacity 2 X 1000 Ltrs.

iii) Fluid medium Emulsion (95% clean &

neutral water with 5%

soluble oil)

POWER TRAIN / ENERGY TRAIN

Electricals for Shortwall operation installed at main gate

in Energy/ Power Train (on 14 trolleys). Transformers, Circuit Breakers, Gate End boxes, Water

spray pump, Power Packs, Emulsion tanks, Face Communication system, Lighting Transformer hoses/cables in the circuit.

Operating voltage is 1.1KV.

CYCLIC METHOD OF OPERATION

Coal Cutting by Shearer

+ Advancing of

(Powered Supports + Shifting of AFC )

Shifting of Powered

Support of advanced galleries

and OC Props of Gate Roads

COAL WINING & EVACUATION OPERATION

Trunk Belts

BSL + Crusher

Coal Cutting by

Shearer

At Surface

Bunker

Gate Belt Conveyor

AFC

LAYOUT OF EQUIPMENT AND STRATA MONITORING INSTRUMENTS AT THE

SHORTWALL PANEL

Dip: 1 in 51 Top Gate

(Main Gate)

Bottom Gate

(Tail Gate)

UNDERGROUND COAL MINING

Background • UG coal mining has travelled from early pick & shovel

mining to today’s fully mechanised power supported longwall faces producing 10 mty with ease.

• During its history mining methods and matching equipments have evolved, by complimenting each other to achieve higher production, productivity and safety

• For a focused discussion sake, only those equipment which are used underground, are covered in the presentation

General equipment requirements

• Must confirm to Indian Electricity Rules 1956.

• Must be approved by Directorate General of Mines Safety (DGMS).

• Depending upon the degree of gassiness, the relevant regulation for Intrinsically safe and FLP (Flame proof) are to be adhered to.

Broad classification of mining methods Common UG mining Methods • Bord/ Room & pillar

– Development – Depillaring

• With caving • With stowing

• Long wall – Advancing – Retreating

Special UG mining methods • Blasting gallery • Yankowice etc.

Challenges ahead

• Continuously declining trend of production from underground mines, particularly in CIL, is a matter of grave concern.

• By 2024-25, production from underground mines is to be increased by about 3 times from the present level – a very challenging and daunting task for CIL.

• This would need to plan strategically to increase rate of output from mines.

Possible options to meet the challenge

• Introduction of suitable mass production technology such as,

– Longwall,

– Continuous Miner (CM), and

– Low Capacity Continuous Miner (LCCM).

• Application of Universal Drilling Machine (UDM) with SDLs and LHDs for improving rate of output in B&P method of working.

Longwall mining technology

• Application of longwall technology in future would be limited due to non-availability of suitable geological patches,

• The contribution of longwall mining technology is expected to be low and therefore, may not be considered the technology for future for the Indian coal industry as on today.

• CMPDI has a massive plan for detailed exploration during the XI Plan period in the regionally explored green-field areas. It is expected that a few projects with longwall technology would come up in Trans-Mand sector of Mand-Raigarh coalfield also.

CM, LCCM, and LHDs with UDM

• Continuous miner technology has been introduced into three mines of CIL – one each in SECL, WCL, and ECL, and has given encouraging results.

• Indigenously developed LCCM has been recently introduced in one mine of WCL and is to be introduced in SECL as well.

• A total of 42 additional CM/ LCCM sets are envisaged to be deployed in CIL mines during XI Plan period producing to the tune of 17.63 Mt by the terminal year 2011-12. Four projects - two in ECL (Tilaboni & Shyamsundarpur/ Sarpi Ph-I) and one each in WCL (Murpar) and MCL (Jagganath) – have been identified for implementation on turnkey basis.

• LHDs with UDM has also shown encouraging results.

UG Mining methods

Type of equipments • Transportation

– Conveyors • Belt conveyors

• Chain conveyors

– Haulages • Direct haulage

• Endless haulage

• Main & tail haulage etc.

– Winding systems • Drum winder

• Friction / koepe winder

– Man riding systems

– Shuttle/ Ram cars

– Locos

• Winning & loading equipments – Drilling machines

• Hand held

• Tyre/ crawler mounted

– Road-header

– Continuous Miner

– Side discharge loader

– Load haul dumper

Type of equipments • Ventilation fans • Pumps • Safety related equipments

– Self contained self rescuers – Gas monitoring devices

• Shot firing equipment

• Supports – Shield type hydraulic power

support – Individual hydraulic/ friction/

screw supports – Monitoring devices – Roof bolter

• Hand held • Crawler mounted

• Communication systems – Conventional wire based – From surface to UG- wireless

and from UG to surface – Combination of wire and microwave

Type of equipments • Continuous miner

package (For development &

extraction)

– Continuous miner* - 1

– Shuttle cars - 2

– Twin/ Quad bolter* - 1

– Feeder breaker - 1

– Power pack - 1

– Mobile goaf edge support (Optional) -2

* In some package both the machines are

integrated into one

• PSLW package For extraction

– Shearer - 1

– Powered support - 1 SET

– Armoured Face Conveyor - 1

– Stage loader - crusher - 1

– Power pack - 1

For Development

– Continuous miner package or

– Roadheader package

UG Mining equipments • Side discharge loader (SDL)

• Load haul dumper (LHD)

UG Mining equipments - Road header

UG Mining equipments – Continuous Miner

UG Mining equipments – Shuttle car

UG Mining equipments – Roof bolter

UG Mining equipments – Shearer

UG Mining equipments – Powered support

UG Mining equipments – Powered support Longwall Face

Bolter miner in operation (Animation)

ClickMe.exe

ClickMe.exe

Continuous miner in operation (Animation) • 5-entry_R&P.exe

5-entry_R&P.exe

5-entry_R&P.exe

5-entry_R&P.exe

Coal India’s plan for enhancing UG coal production – Projections

Company

Production (Mt)

2006-07

(Actual) 2011-12

Increase

over 06-07

ECL 8.27 16.73 8.46

BCCL 4.90 6.00 1.10

CCL 1.96 3.30 1.34

WCL 9.92 11.92 2.00

SECL 16.20 23.78 7.58

MCL 1.97 4.40 2.43

NEC 0.11 0.40 0.29

Total 43.32 66.53 23.21

Coal India’s plan for enhancing UG coal production – Equipment requirement (XI Plan)

Particulars ECL BCCL CCL WCL SECL MCL Total

SDL (Existing) 110 117 14 135 385 19 780

Additional 117 47 30 0 76 0 270

LHD (Existing) 24 2 8 105 57 29 225

Additional 3 0 2 25 42 14 86

CM (Existing) 1 0 0 2 2 0 5

Additional 9 2 2 10 13 5 42

PSLW (Existing) 3 1 0 0 1 0 5

Additional 1 2 0 2 1 0 6

Coal-mining Method

2. Mining Technology of China

Coal-mining method

Single LWM

on the strick

Longwall mining

Thin & mid-thick seam

Sublevel caving

Thick & super thick seam

Single LWM

on the dip

Sharp angle

coal mining Pillar and

chamber mining

Hydraulic coal mining

Stowing coal

mining

Pneumatic

stowing Hydraulic

stowing

others

Overhand mining Oblique slicing Shrinkage stoping, and so on

Full seam mining

Inclined slicing

Top-slicing

system of

sublevel caving

On the strike

Flexible shield

mining in the

false dip

• Room and pillar mining (under building)

• Blastwinning technology

• Conventionally mechanized coal wining technology (small scale mines)

• Full-mechanized coal wining technology

• Full-mechanized top-coal drawing mining method

Coal-mining Method


Full-mechanized top-coal caving technology

Yield support

Coal wining machine

Front flight conveyor

Full-mechanized workface

Back flight conveyor


Auxiliary transport

• Auxiliary transport ：personnel,

materials and facilities, and so on.

• Underground auxiliary transport: mine

locomotive, trackless transport,

overhead rope monorail, road railer,

endless-rope haulage.


Underground mine locomotive

Track transport

Mine locomotive

Trackless transport conveying yield support

Trackless transport conveying people

Overhead monorail

Diesel engine

Battery engine

Road wailer

Diesel engine

Diesel engine road wailer running on oriented track, driven by diesel engine.

Underground Overhead

Conveyor for People

Conveying people in flat or inclined roadway.

System sketch

Mine hoist machinery

Hoist drum diameter: 6.0m Power: 5000kW Velocity: 12m/s

3. Manufacture& Equipment of CCI

Coal wining machine

Power: 2150 kW

Mining height: 1.1～6.5m

Kinds: Single arm, double

arms, big angle


Flexible flight conveyor

Capabality:100~3000t/h Power:100~2000kW Pan width:0.4~1.2m Double straps in the middle, side unloading


Sublevel caving hydraulic support

Support strength: 10000kN Support height: 1.8~4.0m


High Mining Height Hydraulic Support

Electricity Hydraulic control, velocity<8s

Support strength: 12000kN

Support height:6.5m


Belt conveyor

Belt strength:250~6300N/mm Belt width:0.6~2.0m Conveyor capability: 150~5000t/h


Road-heading machinery

Producing tunneling machine, continuous miner, driving anchor machine, driving& boring machine. Power:50～200kW Section area:10～25m2


Tunneling machine

Tunneling machine Driving anchor machine Continuous miner

Changeable blade angle Blade Diameter 4.0m Air quantity 600m3/s, negative pressure 4500Pa

Mine ventilation


Production capacity designed: 15.0Mt/a ( largest mine being put into operation currently) Drift tunneling，belt conveyor length reaches 7km Full-mechanized top-coal caving workface , 10.0Mt/a high efficiency。 Trackless transport

4. Selection Projects Designed by BHEC

Introduction to some selection projects--（Tashan）

Introduction to some selection projects--（Huojitu）

Output：10.0Mt/a Drift tunneling Large cutting height face, mining height 5.5m 270workers, average efficiency: 74t/worker

矿井工作面设备地面调试

Vertical shaft, the net diameter reaches 8.2m, the deep reaches 580m Main vertical shaft equipped with two sets of skip, auxiliary shaft headframe a set of wide skip and a set of riding skip

Auxiliary shaft headframe Main shaft headframe

Introduction to some selection projects--（Tunliu）

4、矿井建设的外部条件

Three-dimensional sketch of Tunliu mine development

Main vertical shaft

North

airshaft

Coalface of south-1 mining area

Auxiliary

vertical shaft

Central airshaft

Coalface of north-1 mining area

Tunneling face

Full mechanized top coal caving with high gas condition Output of face ： 3.0Mt/a

Belt conveyor Belt conveyor

Hoisting Belt conveyor

Ground

Underground

Underground coal transport systems——Belt conveyor

Introduction to some selection projects--（Tunliu）

Huangyuchuan mine of Shenhua Group(10.0Mt/a)

Inclined shaft mixed with vertical shaft development


Inclined shaft, large cutting height face in whole seam, output of face is 8.0Mt/a

Introduction to some selection projects--（Sihe）


Vertical shaft

tunneling

3、巷道掘进

Frozen depth more than 500m

Construction shaft speed over 100m per month

Rock drift tunneling: drilling

急倾斜煤层

Roadway layout in coal seams

Roadway layout in rocks

fully-mechanized coal winning machine in coal seams

drilling in rocks

Anchor，metal net ，injection and

anchor cable

Concrete or reinforced Concrete

Type steel support set

Roadway tunneling and support

Drift tunneling：shield TBM

副立井

1-disk-cutter;2-head frame;3-horizontal supportplate;4-roof bolter;5-driver room;6-oblique belt conveyer;7-transfermachine;8-gantry vehicle;9-laser orientation instroment;10-ring supports mschine;11-tramcar;12-electric locomotive

Coal roadway tunneling：roadheader

1-roadheader；2-transfermachine；3-telescopic；4-slideway 5-dedusting fan;6-scalable;7-jackleg drill

Tunneling machine Continuous miner

HYDRAULIC PROPS (40 Te) AT THE GATES OF

SHORTWALL PANEL

• 110 tonnes per day (For a 5-heading district having 3 SDLs)

SIDE DISCHARGE LOADER

• 200 tonnes per day (For a 5-heading district having 3 LHDs)

LOAD HAUL DUMPER

• 1,200 to 2,400 tonnes per day (depending on the seam thickness)

CONTINUOUS MINER

• 3,280 tonnes per day onwards (1 MTY) POWERED SUPPORT LONGWALL

184

PRODUCTIVITY IN UG

• Longwall

• Continuous Miner (CM)

• Low Capacity Continuous Miner (LCCM)

Introduction of mass production technology

• Application of Universal Drilling Machine (UDM) with SDLs and LHDs for improving rate of output in B&P method of working.

Application of UDM, SDL & LHD

185

TO ENHANCE UG COAL PRODUCTION IN INDIA

ENVIRONMENTAL & SAFETY ISSUES

• During UG mining, the inherent dangers of roof & side fall, fire, explosion, noxious gases, water inundation etc. are to be dealt with.

• Roof & side fall remains the most common cause of UG mine accidents.

• Switching to mass production technology will reduce the no. of accidents due to strata control and those related with the handling of explosives.

• Extensive R&D work is being done to limit accidents due to roof fall. One such major R&D work for detecting of early bed separation and hidden slips accompanied with audible warning is going on in IIT Kharagpur

• Use of bolting techniques will reduce the chances of

accidents in semi-mechanised mines 186

PARTIAL METHODS OF EXTRACTION

• Limited Span Method

• Wide & Stall Method

• Chess Board Method

• Yield Pillar Method

• Non Effective Width of Extraction

• Stable Pillar formation as Final Operation


SUITABILITY

• Extraction under built up area and other important surface features.

• To ensure that cracks due to mining do not reach surface or to the upper seam.

• To work a lower seam when upper seam is virgin or developed.


LIMITATIONS

• Physico-Mechanical Analysis of immediate roof/strata. • Stability inculcation of in seam workings. • Status of Surface Features. • Overlying / Underlying seams / workings. • Depth of workings. • Cavability of strata. • Geological features. • Socio-political environment. • Mine Economics. • Conservation. • Strategic actions for Long Term prevention of mine fire. • Quantum of blockage of reserve.


ADVANTAGES

• Liquidation of blocked coal in standing pillars.

• Protecting Surface features.

• Mitigation of socio-political issues related to evacuation / shifting.

• Avoidance of R & R modalities.

• Recovering a part of blocked property, which might be a total forfeiture otherwise for the reason stated above.

• Subsequent direct & indirect economical gains.


METHODOLOGY


WIDE & STALL METHOD

This method aims at widening existing galleries of Bord & Pillar workings, up to the extent, so that roof fall never takes place in the span. This method necessitates strong immediate roof, with moderately thick seam.


CHESS BOARD METHOD

This method necessitates complete extraction of selected pillars, leaving alternate pillars, untouched and as standing on for ever, so that subsidence must not occur. This method necessitates strong immediate roof as well as higher compressive strength of coal, providing adequate resistance for subsidence.


YIELD PILLAR METHOD

In this method of mining, pillars or stocks are left in the goaf as per designed scheme of pillar extraction. These pillars and stocks are of a definite dimension which neither makes them too strong nor too weak. When roof weight comes, these pillars get crushed and allow the roof to come down smoothly.


NON EFFECTIVE WIDTH

This method involves complete extraction of selected chain of pillars with precisely determined extraction width of panel, so that subsidence never reaches the surface.


STABLE PILLAR / REMNANT FORMATION

This is the youngest evolution of Partial Extraction Method. This method necessitates reduction of original coal pillar, by driving narrow galleries across it, leaving remnants as Stable Pillar for ever.



• Long Wall Mining

• Mass Production Technology with Continuous Miner & Shuttle Car Combination

• Short Long Wall Mining

• High Wall Mining


LONGWALL MINING

Suitability & Advantages:

• Flat & Moderate thick coal seams.

• Nearly full extraction

Limitations:

• Fair / Good cavability of roof strata.

• Seam continuity.

• Preferably flat seams.

• Seams, free from major geological disturbances.


LONGWALL MINING

Operational Experience:

SECL has Long Wall workings in three of its under ground mines, i) Rajendra, ii) Kumda (New) & iii) Balrampur UG.


LONGWALL MINING

Operational Constraints:

• Strata Management

• Difficulties due to shallow depth of cover

• Intrusion of hard sand stone

• Warranty failures of major hydraulic components

• Thinning of coal seams

• Spares management



• Familiarity of Room and pillar-mining due to resemblance of Bord & Pillar layout.

• Familiarity of equipment

• Flexibility of mining method due to mobile equipment.

• Lower Capital cost for high production and productivity as compare to Long wall method.

• Not much preparatory work/infrastructure is needed for introduction of this system.


Limitations:

• Flat / Mild gradient seams.

• Seam thickness should be moderate, not very thick.


Operations:

SECL has experienced this method of mining at two of its under ground mines, Anjan Hill Mine & NCPH Colliery successfully.

MASS PRODUCTION TECHNOLOGY Development

Figure 1 A Typical 5 Road Mining Layout


Extraction

Roof bolts were used for systematic supports in and around working area as well as in the breaker lines at the goaf edges during the depillaring of the panel.

SHORT LONG WALL MINING

• This method of mining envisages the extraction of standing on

pillars (formed due to Bord & Pillar development) with the help of Self Walking Powered Supports and Shearer as that if a PSLW retreat face.

• But the gallery openings are suitably supported in advance of

extraction to attain adequate support resistance to restrict movement of Abutment Loading with in working areas.

• SECL is at the verge of commissioning a Short Wall Face at

Balrampur mine.

SHORT LONG WALL MINING

Suitability & Advantages: • Faster extraction of long standing on pillars. • Good quality roof. • Nearly full extraction of seam. Limitations: • Applicable to developed B & P workings.

HIGH WALL MINING

In this technology coal seam is

approached by trench / contour / bench. Coal thus exposed on either side of the trench can be extracted by remotely operated Continuous Miner, leaving adequate remnants between two consecutive webs. SECL is shortly going to introduce this methodology at few of its old mines.

HIGH WALL MINING

Suitability: Enables recovery of coal from surface pits -

– that have reached final high wall position due to uneconomic stripping ratio or

– where coal has become sterilized due to surface constraints.

Limitations: stability of web-pillars & sustainability of roof have to be

established by scientific investigations.

Advantages: • Minimises safety risks as persons are not required at active

working faces. • Coal is recovered from very difficult situations, other wise it

could have been forfeited for good.

MINING WITH SDL / LHD COMBINATIONS


CABLE BOLTING – REMOTE LHD COMBINATION

• This method is very useful for extraction of thick seams.

• In SECL, this is being practiced at Chirimiri Area, where thickness up to 7m is being extracted successfully in conjunction with Remote Controlled SDL.

• Basically this method is Rib Slice pillar of extraction and supporting of high roof is being ensured by hanging cable bolt in the goaf.



– Very effective extraction of thick seam up to 7m. – Preferably Degree-1 of gassiness seam. – Fair / good roof condition. – Longer Incubation period. – Low capital intensive than BG method.


Limitations: – This method is not yet proved for seam thickness

more than 7m. – Not suitable for higher degree of gassiness. – Not suitable under poor roof condition. – Not suitable shorter incubation period.


BLASTING GALLERY METHOD

SECL is going to introduce this mining method at Anjan Hill Mine, Chirimiri Area. Blasting Gallery method is cyclic in nature involving of following operations.

• Room Drivages / Splitting of pillars & POTATO Blasting • Ring Drilling by Jambo Drills • Charging , Stemming & Blasting of Ring Holes • Loading of Coal ( Remote controlled LHD) • Induced Blasting , if required.

BORD & PILLAR WITH SDL / LHD COMBINATIONS

To over come the constraints of conventional Bord & Pillar

workings with SDL / LHDs, Universal Drilling Machines have been introduced for coal and roof drilling, in several mines of SECL with following advantages,

• Faster rate of both coal and roof drilling. • Faster and better coal preparation. • Eliminations of manual drilling, resulting faster and effective

roof bolting. • Better utilization / reduction of man power. • Better safety due to elimination of manual drilling. • Higher production and productivity.

CONCLUSION

Energy, the basic requirement of the country, remains largely

dependant on coal. Under Ground mining, dictates its pioneer status in the anticipated Socio – Economics of the country. Hence Modern mechanization of Indian under grounds, Development of mechanization culture and strategic success out comes are the yard sticks of future Indian Coal Industry.

UNDERGROUND MINING TECHNOLOGY OPTIONS

BORD & PILLAR

LONGWALL

BORD & PILLAR

• MANUAL

• SDL & LHD

• CONTINUOUS MINER

• UNDERGROUND MINING TECHNOLOGY IN INDIA AND ABROAD:

• - Shuttle Car – Gathering Arm Loader Combination. • - Slusher/Coal Scrapper • - Bord and Pillar Technology with SDL/LHD as loading and suitable

compatible conveying equipment. • - Sub-level caving. • - Limited Span Mining • - Wide Stall Mining • - Longwall with Single ended Ranging Arm Drum Shearer and hydraulic/friction

props. • - Mechanised Longwall with Powered Support equipment & DERD Shearer. • - Continuous Miner and Shuttle Car Combination. • - Road Header/Alpine Miner for faster heading development in coal seams. • - Blasting gallery technique of extraction in moderately thick coal seams

with remotely operated SDL/ LHD .

(c) Strategic underground mining technology in SECL:

Mechanisation culture and adoption of new technology is continued in SECL since long. Some of the new technologies as planned for implementation in SECL mines are :- (i) Low Capacity Continuous Miner(LCCM)

- Planned to be introduced in Rani-Atari UG mine of Chirimiri Area. - Likely to be commissioned by January, 2008 to produce a minimum level @ 600 TPD from both development/depillaring in Bord and Pillar layout with 2.2m to 2.4m thick coal seam with 5.4m width galleries where supports are normally planned by resin grouted roof bolts. -There is future scheme for introduction of such equipment in seven underground mines in SECL besides Rani-Atari UG mine by XIth Plan period. (ii) Shortwall Technology(Fig.3):

- Suitable for extraction of developed coal pillars planned for Balrampur underground mine. - Already implemented to extract Passang seam(2.2 mtr. – 2.8 mtr.). It is an R&D Project which will be tried for the first time in the country and perhaps in the globe with imported equipment from P. R. China consisting of 4x650 Te.(108 Te/m2 ) capacity Powered Supports.

(iii) Blasting Gallery Method(Fig.4a & b) - Will be operated shortly at Anjanhill mine of Chirimiri Area, SECL. L -likely to be commissioned in this financial year 2007-08. -Remote Controlled high capacity LHD (3m

3) will be operated to evacuate

blasted coal at depillaring faces by this technology. (iv) High Wall Mining - This new technology in SECL as well as in the country likely to be introduced where neither the established opencast nor the conventional underground mining techniques are possible to be used to exploit the coal seams so proposed economically. - It is a remotely operated mining method to extract coal from thin seams or coals from underlying coal seams in the Highwall of a surface mine which has reached the quarriable limit & uneconomical stripping ratio or local surface constraints limit further surface mining operation. - SECL would be among the pioneering companies to introduce it under the new initiations for advanced technology.

(v) A small quantum of coal production from conventional manual districts in the underground mines of SECL is also planned for conversion to mechanized operation within a short spell of time.

SDL & LHD

http://www.mining-technology.com/projects/samancor/index.html

CONTINUOUS MINER

LONGWALL

• INDIVIDUAL PROPS – SOLID BLASTING

– SHEARER

– PLOUGH

• POWERED SUPPORT LONGWALL – SINGLE SLICING

– MULTIPLE SLICING

– BLASTING GALLERY

LONGWALL MINING

PLOUGH

OTHER MINING TECHNOLOGY OPTIONS

HIGH WALL MINING

AUGER MINING

PUNCH LONGWALL

HYDRAULIC MINING

HIGH WALL MINING

HIGH WALL MINER

AUGER MINING

PUNCH LONGWAll

HYDRAULIC MINING

COAL PRODUCTION PROGRAMME OC/UG BREAK-UP

COM-

PANY

OC/

UG

ACTUAL

(Mt)(%)

TARGET, Mt (%)

06-07 07-08 11-12 16-17 21-22 26-27

ECL OC

UG

TOTAL

22.2 (72.86)

8.27 (27.14)

30.47

23.18 (69.38)

10.23 (30.62)

33.41

32.84 (71.39)

13.16 (28.61)

46.00

34.86 (72.63)

13.14 (27.38)

48.00

32.20 (71.97)

12.54 (28.03)

44.74

32.20 (72.18)

12.41 (27.82)

44.61

BCCL OC

UG

TOTAL

19.30 (79.76)

4.90 (20.24)

24.21

20.62 (81.83)

4.58 (18.17)

25.20

24.72 (82.40)

5.28 (17.60)

30.00

28.75 (82.14)

6.25 (17.86)

35.00

31.39 (74.74)

10.61 (25.26)

42.00

31.70 (76.18)

9.91 (23.82)

41.61

CCL OC

UG

TOTAL

39.36 (95.26)

1.96 (4.74)

41.32

42.00 (95.45)

2.00 (4.55)

44.00

75.60 (96.92)

2.40 (3.08)

78.00

112.60(97.91)

2.40 (2.09)

115.00

114.29(97.25)

3.23 (2.75)

117.52

115.87(97.30)

3.21 (2.70)

119.08

WCL OC

UG

TOTAL

33.30 (77.07)

9.92 (22.93)

43.21

32.39 (76.39)

10.01 (23.61)

42.40

34.38 (76.40)

10.62 (23.60)

45.00

34.21 (76.02)

10.79 (23.98)

45.00

26.65 (67.28)

12.96 (32.72)

39.61

22.36 (60.66)

14.50 (39.34)

36.86

SECL OC

UG

TOTAL

72.30 (81.69)

16.20 (18.31)

88.50

74.04 (80.92)

17.46 (19.08)

91.50

91.30 (82.25)

19.70 (17.75)

111.00

119.00(85.00)

21.00 (15.00)

140.00

109.11(81.57)

24.66 (18.43)

133.77

107.05(86.01)

17.41 (13.99)

124.46

NCL OC

UG

TOTAL

52.16 (100)

-

52.16

58.00 (100)

-

58.00

70.00 (100)

-

70.00

80.50 (100)

-

80.50

81.50 (100)

-

81.50

81.50 (100)

-

81.50

COAL PRODUCTION PROGRAMME OC/UG BREAK-UP (CONTD.)

COM-

PANY

OC/

UG

ACTUAL

(Mt)(%)

TARGET, Mt (%)

06-07 07-08 11-12 16-17 21-22 26-27

MCL OC

UG

TOTAL

78.03 (97.54)

1.97 (2.46)

80.00

85.60 (97.27)

2.40 (2.73)

88.00

134.00(97.81)

3.00 (2.19)

137.00

193.40(98.17)

3.60 (1.83)

197.00

179.00(97.86)

3.92 (2.14)

182.92

167.00(97.90)

3.59 (2.10)

170.59

NEC OC

UG

TOTAL

0.94 (89.52)

0.11 (10.48)

1.05

1.70 (85.00)

0.30 (15.00)

2.00

3.10 (88.57)

0.40 (11.43)

3.50

3.10 (88.57)

0.40 (11.43)

3.50

- -

CIL OC

UG

TOTAL

317.59(88.00)

43.32 (12.00)

360.91

337.53(87.78)

46.98 (12.22)

384.51

465.94(89.52)

54.56 (10.48)

520.50

606.42(91.33)

57.58 (8.67)

664.00

574.14(89.42)

67.92 (10.58)

642.06

557.68(90.14)

61.03 (9.86)

618.71

COAL PRODUCTION PROGRAMME CIL

54.56 57.58 67.92 61.03

337.53

465.94

606.42 574.14 557.68

46.9843.32

317.59

618.71642.06664.00

520.50

384.51360.91

0

100

200

300

400

500

600

700

2006-07

(Actual)

2007-08 2011-12 2016-17 2021-22 2026-27

Year

Co

al

Pro

du

cti

on

Targ

et,

Mt

Underground Opencast Total

COAL PRODUCTION PROGRAMME ECL

10.23 13.16 13.14 12.54 12.41

23.18

32.84 34.86 32.20 32.20

8.27

22.20

44.6144.7448.00

46.00

33.4130.47

0

10

20

30

40

50

60

2006-07

(Actual)

2007-08 2011-12 2016-17 2021-22 2026-27

Year

Co

al

Pro

du

cti

on

Targ

et,

Mt


COAL PRODUCTION PROGRAMME BCCL

4.58 6.2510.61 9.91

20.6224.72

28.75

31.39 31.70

5.284.90

19.30

41.6142.00

35.00

30.00

25.2024.21

0

5

10

15

20

25

30

35

40

45

2006-07

(Actual)

2007-08 2011-12 2016-17 2021-22 2026-27

Year

Co

al

Pro

du

cti

on

Targ

et,

Mt


COAL PRODUCTION PROGRAMME CCL

2.00 2.40 2.40 3.23 3.21

42.00

75.60

112.60 114.29 115.87

1.96

39.36

119.08117.52115.00

78.00

44.0041.32

0

20

40

60

80

100

120

140

2006-07

(Actual)

2007-08 2011-12 2016-17 2021-22 2026-27

Year

Co

al

Pro

du

cti

on

Targ

et,

Mt


COAL PRODUCTION PROGRAMME WCL

10.01 10.62 10.79 12.96 14.50

32.3934.38 34.21

26.65 22.36

9.92

33.30

36.8639.61

45.0045.0042.4043.21

0

5

10

15

20

25

30

35

40

45

50

2006-07

(Actual)

2007-08 2011-12 2016-17 2021-22 2026-27

Year

Co

al

Pro

du

cti

on

Targ

et,

Mt


COAL PRODUCTION PROGRAMME SECL

17.46 19.70 21.00 24.66 17.41

74.04

119.00 109.11107.05

16.20

91.30

72.30

88.50 91.50

111.00

140.00133.77

124.46

0

20

40

60

80

100

120

140

160

2006-07

(Actual)

2007-08 2011-12 2016-17 2021-22 2026-27

Year

Co

al

Pro

du

cti

on

Targ

et,

Mt


COAL PRODUCTION PROGRAMME NCL

58.0070.00

80.50 81.50 81.50

52.16

81.5081.5080.50

70.00

58.0052.16

0

10

20

30

40

50

60

70

80

90

2006-07

(Actual)

2007-08 2011-12 2016-17 2021-22 2026-27

Year

Co

al P

rod

uct

ion

Tar

get

, M

t

Opencast Total

COAL PRODUCTION PROGRAMME MCL

2.40 3.00 3.60 3.92 3.59

85.60

134.00

193.40 179.00 167.00

1.97

78.03

170.59182.92

197.00

137.00

88.0080.00

0

50

100

150

200

250

2006-07

(Actual)

2007-08 2011-12 2016-17 2021-22 2026-27

Year

Co

al

Pro

du

cti

on

Targ

et,

Mt


COAL PRODUCTION PROGRAMME NEC

0.30 0.40 0.40

1.70

3.10 3.10

0.11

0.94

3.503.50

2.00

1.05

0

1

1

2

2

3

3

4

4

2006-07 (Actual) 2007-08 2011-12 2016-17

Year

Co

al

Pro

du

cti

on

Targ

et,

Mt


• Introduction of Continuous Miner Technology :

• After introduction of Continuous Miner technology at Tandsi mine on Risk & Gain sharing basis & at Kumbharkhani Mine with a minimum and guaranteed production on per tonne basis, the similar technology to be introduced in the following 6 mines :

• The Board of Directors has approved for introduction of Continuous Miner Technology.

• i. Saoner-I UG Expn. Mine ii. Maori UG Mine iii. Sarni UG iv. Nandan-II UG Dhau North Block v. Dhankasa vi. Borda UG Mine

• In 1st phase, Saoner-I & Maori UG Mines has been taken up for Introduction of Continuous Cutting Technology. Tender floated earlier has been cancelled. It is in the process of further approval of Board for the deviations from CMC Turnkey manual. The Tenders will be floated shortly.

• Introduction of CCT in the remaining mine/block will be taken up in 2nd phase.

• Application of Man-riding System in Mines

• It has been decided to introduce Man-Riding System in certain underground mines, where the workings are very deep and far from the surface. As it takes longer time to travel to reach at the working face of the mine and at the same time it leaves all the work persons fatigued while going down and coming up the mine. Taking this view into consideration the Rail Car System has been introduced at two mines.

• i. Tandsi 1&2 Mine ii.Maori UG Mine

• At following mines, the man-riding system is under installation & will be commissioned shortly :

• Saoner No. 1Chair lift systemShobhapur No. 1Rail car system & chair lift systemTawa MineChair lift systemKumbharkhaniRail car system

• Man-riding system in 2nd phase :

• i. Ballarpur 3&4 ii. Chhattarpur iii. Saoner No.2 iv. Saoner No.3 v. Tandsi 3&4

• Introduction of Mass Production Technology • Global bid for introduction of Mass Production technology in respect of

Development, Construction & Operation of high capacity underground mines on turnkey basis had been floated for two blocks identified are :

• 1. Murpar Expn., Umfer Area (2.0 Mty capacity). • 2. Borda Block, Wani North Area (2.0 Mty capacity).

Status � Since, there was no response from the short listed Bidders, the aforesaid tender was cancelled. The draft NIT for Murpar Expn., Borda Block and Nand Block has been uploaded on WCL's website, with a view to have Pre-NIT meeting with prospective Bidders on 26.08.2010 to further modify the Bid documents for re-tendering.

• 3. Nand Block, Umrer Area (1.00 Mty capacity). Alongwith the draft NIT for Murpar Expn., Borda Block and Nand Block has also been uploaded on WCL's website, with a view to have Pre-NIT meeting with prospective Bidders on 26.08.2010 to further modify the Bid documents.

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• Increase in Underground Production: • 2nd Continuous Miner at Sarpi commissioned in Sept. 2010. • Re-organization of UG districts started with introduction

of mechanized loading replacing manual loading in phases. • Tender for procurement of 113 more SDLs is under finalization to

avoid manual loading and enhance safety. • LOI issued for PSLW at Jhanjra • ECL Board has approved in principle deployment of 6 more

Continuous Miners in different UG mines. • A few number of UG reserves like Narayankuri, Dhangajore,

Puapur, Sonepur Bazari etc. have been identified for high capacity UG mines under MDO concept.

•

INTRODUCTION

• - The gap between production and demand of coal in future can not be totally met by the depleting Opencast mines. Hence immediate and urgent attention is required to plan and execute large underground coal mining projects.

• - For bulk production of coal at a faster rate from underground mining, particularly at depth, the proven technology world over is Longwall.

INDIAN LONGWALL

• - PAST EXPERIENCE:

• - Introduction of advanced technology system in

• Indian coal mining industry marked a major step

• with the installation of first mechanized Longwall

• Powered support face at Moonidih in August 1978.

• - In 25 years about 20 mechanised longwall sets from

• - U.K, Russia, China, France have been tried in

• various locales, mostly funded by GOI.

• Mechanised Longwall mining was introduced in India about 25 years back with much fanfare but could not fully meet the expectations of the mining industry for various reasons, while China starting at the same time was quite successful and even exported their Longwall packages to India.

PAST EXPERIENCE

- In early nineties, higher capacity of Longwall powered supports were introduced.

- These faces were mostly succesful except the collapse of Churcha and Kotadih.

- With the perspective of history of Longwall of China, US etc and the need of understanding the technology these should be treated as experiences rather than failures.

REASONS FOR THE UNSUCCESSFUL ATTEMPTS TO INTRODUCE

LONGWALL TECHNOLOGY IN INDIA

• MAIN REASONS CAN BE GROUPED UNDER TWO HEADINGS:

• TECHNICAL ASPECTS

• FINANCIAL CONSTRAINTS

Reasons which led to lower production than expected:

• Integration problems between the equipment

• Starting up phase takes much longer

• Training of personnel is more difficult & time consuming

• Problems in maintaining the equipment

• Infrastructure was not suitable to support the higher production

• Geological conditions were more difficult than expected

REASONS FOR SLOW PROGRESS OF LONGWALL

• Large expansion in opencast mining in the past two decades provided cheaper and safe method for bulk coal production and as a result long wall had to take back seat.

• Clear strategies were not pursued for its sustenance as there was mixed results from long wall in the early years of its introduction.


• Long walls were introduced mostly in the blocks left over by working Bord and pillar method. Clean and extensive blocks have not been identified. Even the smaller blocks, which were identified, were of inferior grade coal.

• Long wall had to co exist with the conventional mining in most of the mines, which caused management problems.

• There were some deficiencies in the imported spares management and the supplies were not reaching in time.


• Coal companies were sensitive to the failures of a few long wall faces and were not prepared to risk huge investments.

• Development could not keep pace with the extraction of Long wall panels, slow progress in dip has delayed the formation of Long wall panels and affected the performance.

PRESENT & FUTURE

• With the likely reduction of contribution from Open cast and the more or less stagnant production from Underground by Conventional methods, it is time that an impetus is given to boost Long wall Technology to able to meet the future energy needs of the country.

• On the positive side, coal companies have now gained experiences right from senior executive level to front line workforce to be able to plan, execute and work longwall faces. What are required are policy decisions and logistics.

CAUSES FOR FAILURE OF LONGWALL IN THE INITIAL STAGES

• Geo-mining Conditions • Difficult geo-mining conditions were experienced in almost all the

faces • Moonidih met with a series of step faults at the face, the existence of

which were not known at the time of development. • The roof at Pathakera and Dhemo main mines proved to be difficult

caving roofs. • Coal was found to be extremely hard and abrasive in Pathakera and

Singareni. • The face at Seetalpur encountered a massive inrush of water from

the overlying seam1. • This highlights the need to incorporate geology and geotechnical

engineering into the management process to build a data base of experience for dealing with geotechnical conditions. The revenue lost per day per hour of downtime due to geological features on a 3000 t Longwall is sufficient to employ a fulltime geologist for the order of 10 years.


• Faulty Planning • In mechanised Longwall mining, the performance from the face depends on many

factors and a systems approach is necessary, while designing the layout and in selecting the equipment. Few typical examples of faulty planning are cited :

• The outbye coal clearance system in Seetalpur and Dhemo main mines were inadequate.

• Replacement face could not be made available due to slippage in the drivage programme in Moonidih, Seetalpur and Dhemo main.

• Inadequacy of the conveyor transfer points to handle lumps created problems in coal clearance in Moonidih, Seetalpur and Dhemo main.

• Absence of well designed system for the transportation of materials in all the mines.

• Deficiency in maintenance and engineering setups, workshop facilities etc at Seetalpur and Dhemo main.

• The capacity of shafts or inclines in most of the mines were too low to ensure sustained coal clearance from the face. In some cases, the outbye conveyor was not able to carry the peak outputs and transfer points were also not designed properly.


• Improper Selection • Since mechanised Longwall mining in India was passing through its embryonic

stages, the basic selection of equipment for the first crop of faces was done by equipment suppliers from abroad who were guided by experience from other countries. As a result, the achievements were below the expectations, since major problems cropped up with the selected equipment. Estimation of support requirements was one major problem area and some of the faces

• were equipped with lower rated supports. • Frequent failures of valves, legs, etc and non-uniform setting load of supports led

to a host of complications. Difficulties were also faced with the ranging drum shearer as the power requirements were estimated on the lower side.

• Matching stage loaders with crusher and gate belt conveyor is the basic requisite and cases have occurred where malfunction or absence of lump-breakers have created major jams. Significance of auxiliary items are also to be kept in view as their absence creates operational and maintenance difficulties1.

• Longwall Support Selection Deficiencies

Documents

guide for method of working coal