DRIVAGE OF INCLINES IN MANDLA NORTH COAL MINE

1

• DRIVAGE OF INCLINES IN
  MANDLA NORTH COAL MINE
• of
• Jaiprakash Associates Limited, Noida
• by
• M N Jha M S Sandhu

2
COAL MINING SCENARIO

• Coal mines were nationalized during 1971-73.
• 80 of coal production came from underground mine
  during that era.
• Emphasis was given to develop Opencast mining to
  meet rising demand.
• This trend continued with high level of
  mechanization resulting into only 10 share of
  coal production from underground mines as of now.
• Ministry of Coal identified Coal blocks for
  allocation to be developed scientifically through
  underground method only.

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GENERAL INFORMATION

• Mandla North coal block with coal seams at a
  depth varying from 210 to 300 m was allotted to
  M/S Jaiprakash Associates Ltd.
• It covers an area of 10.41 sq. km.
• Coal seams are highly disturbed with 29 faults in
  the property. The major fault (F2A) with 100m
  throw divides the property in two parts.
• The mine has been planned to extract 1.5 mtpa
  deploying 3 sets of Continuous Miner.
• One set of inclines with one ventilation shaft
  are proposed to access coal seams.

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COAL SEAMS

• Barakar formation contains 5 coal seams splitted
  in to 19 workable/non-workable seams occurring at
  a depth varying from 173-350m.
• The following distinct horizons formed by coal
  seams are found workable.

COAL HORIZON COAL SEAM
TOP SET
1 Seam I B
2 Seam I C
3 Seam II
4 Seam III B
BOTTOM SET
5 Seam IVA/A2
6 Seam VA/A1
7 Seam VB/B1
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METHOD OF WORKING

• It is planned to develop Seam IC initially having
  found in all 24 sectors with Gross reserve of
  45.48 mt since Seam IA has not developed into
  workable thickness and Seam IB coalesced with
  Seam IC at various places.
• Life span for extraction of IB/IC is estimated at
  25 years _at_ 1.5 mtpa.
• Extraction of II/IIIB shall be planned after a
  lapse of 5 years on completion of depillaring of
  the first panel of Seam IB/IC. This sequence will
  be followed for the remaining lower seams.
• It has been decided to work this mine by Bord
  Pillar method with deployment of Continuous Miner
  for driving Trunk headings along rise and dip of
  the property.
• Panels comprising a set of 5 headings with cross
  connecting galleries will be opened on either
  side of the main trunk roadway for lateral
  development.
• 3 sets of Continuous Miners will be deployed to
  achieve the targeted Mine capacity of 1.5 mtpa.

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METHOD OF WORKING (Contd)

• VENTILATION
• The proposed Mandla North Coal Mine has been
  considered as Degree-II Gassy Mine for assessment
  and planning of ventilation requirements.
• 18000cum/minute of air is required to be produced
  by Mechanical system installed in Ventilation
  shaft.
• 3.3 kv, 350kw motors shall be installed.
• These figures has been arrived taking into
  account all relevant DGMS requirements.

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METHOD OF WORKING (Contd)

• EVACUATION OF COAL
• Continuous Miner shall convey the coal into
  Shuttle cars through its bridge conveyor.
• Loaded Shuttle car will discharge coal onto the
  feeder-breaker via coal hopper.
• Coal will be discharged uniformly onto the gate
  belt conveyor from feeder breaker.
• The gate belt in turn will discharge the coal
  onto the trunk belt conveyor and to bunker on the
  surface.
• Mechanically covered trucks will carry the coal
  from bunker to Railway siding for loading into
  the railway wagons.

8
INCLINE DRIVAGE

• A single set of inclines measuring 5.2mX3.5m at a
  gradient of 1 in 4.5 are being driven in the
  centre of the property.
• The above parameters will restrict the length of
  the inclines to 903mx2 with optimum level of
  efficiency both for evacuation of coal and man
  riding system.
• The inclines will pass through Deccan Traps
  (495mx2) and Moturs (348mx2) before intersecting
  the coal bearing Barakars.

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INCLINE DRIVAGE (Contd)

• TECHNOLOGY
• Deployment of Road header - This option was not
  considered because of its unsuitability in Basalt
  having hardness gt8.
• Drilling, blasting with combination of SDL and
  conveyor belt The frequent shifting of Conveyor
  belt along with high level of maintenance makes
  this option unviable.
• Deployment of Jumbo drill, SDL and 150kw haulage
  with 10t skips This has been adopted being the
  most suitable for Indian condition and
  subsequently to be used for man riding.

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INCLINE DRIVAGE (Contd)

• EQUIPMENTS-HAULAGE
• Haulage with man riding provision with following
  specifications have been installed.
• Haulage rating 150 kw
• Rope Speed 2.2 to 2.5 m/sec
• Rope pull 20 Tonnes in 1 in 4.5 gradient
• Rope diameter 25 mm
• Motor RPM 1000
• Drum diameter 1500 mm
• Rope length 1200 m

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INCLINE DRIVAGE (Contd)

• EQUIPMENTS-JUMBO DRILL
• One Jumbo drill capable of drilling both face and
  roof holes in two inclines with following
  specifications has been deployed.
• Make Sandvik HL 510
• Percussion pressure 120-175 bar
• Rotation (max) 175 bar
• Impact power 16 kw
• Feed length 3900mm860mm
• Feed force 9 Kn/120 bar
• Water pump 1 x Water booster pump
• Length 8015 mm
• Width 1700 mm
• Height (without canopy) 1800 mm

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INCLINE DRIVAGE (Contd)

• EQUIPMENTS-SIDE DISCHARGE LOADER
• Two SDLs to load the broken rock into the 10 t
  skip with following specifications.
• Overall length 5428 mm
• Height over canopy 1850-2100 mm
• Ground clearance 205 mm
• Bucket capacity 0.66 cum (side tipping rock
  bucket)
• Gradient to be negotiated 1 in 4.5
• Track width (grouser pads) 330 mm

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INCLINE DRIVAGE (Contd)

• EQUIPMENTS-VENTILATION FAN
• In order to get air flow of 8cum/sec at the face
  end of 900 m long drift, fans of 37.5 kw with
  following specifications are installed in
  respective inclines.
• Fan Pressure 3200 Pa
• RPM 2950
• Voltage 415 V
• Rating of fan motor 37.5 kw

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INCLINE DRIVAGE (Contd)

• BLASTING PATTERN

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INCLINE DRIVAGE (Contd)

• BLASTING PATTERN

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INCLINE DRIVAGE (Contd)
Time Study Time Study
Activity Total Time (In minutes)
Tramming 05
Water connection 15
Scaling (Dressing) 20
Face Drilling 52
Roof Drilling 20
Roof bolting 50
Water dis-connection 15
Tramming 07
Face charging 60
Blasting 10
Entry after blast 20
Face clearance after blast 30
Mucking(Blasting muck clearance) 240
General work(Ducting, lighting etc) 60
Total Time 604 (Say 600 minutes) i.e 10 hours.
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CONCLUSION

• We expect to achieve a progress of 90m per month
  in each incline to touch coal seam within a time
  span of 10-12 months.
• Continuous Miner will be deployed to drive trunk
  heading and for formation of panels.
• 3 set of Continuous Miner along with allied
  equipments shall be commissioned to achieve the
  target production of 1.5 mtpa.

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