DRIVAGE OF INCLINES IN
MANDLA NORTH COAL MINE
of
Jaiprakash Associates Limited, Noida
by
M N Jha & M S Sandhu
1
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.
2
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.
3
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
4
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 @ 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.
5
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.
6
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.
7
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.
8
INCLINE DRIVAGE (Contd)
TECHNOLOGY
 Deployment of Road header - This option was not
considered because of its unsuitability in Basalt
having hardness >8.
 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.
9
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
10
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 – 3900mm+860mm
 Feed force – 9 Kn/120 bar
 Water pump – 1 x Water booster pump
 Length – 8015 mm
 Width – 1700 mm
 Height (without canopy) – 1800 mm
11
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
12
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
13
INCLINE DRIVAGE (Contd)
BLASTING PATTERN
14
INCLINE DRIVAGE (Contd)
BLASTING PATTERN
15
INCLINE DRIVAGE (Contd)
 Time Study
Activity
Tramming
Water connection
Scaling (Dressing)
Face Drilling
Roof Drilling
Roof bolting
Water dis-connection
Tramming
Face charging
Blasting
Entry after blast
Face clearance after blast
Mucking(Blasting muck clearance)
General work(Ducting, lighting etc)
Total Time
Total Time (In minutes)
05
15
20
52
20
50
15
07
60
10
20
30
240
60
604 (Say 600 minutes) i.e 10 hours.
16
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.
17
18
19
20