3. Mining Methods
• Coal is mined by two main methods - surface
or ‘opencast’ mining and ‘underground’
mining.
• The choice of method is largely determined by
the depth, geology of the coal deposit and
other factors.
• The majority of the world's coal production is
coming from Opencast mines.
• This scenario is same in India also.
12. Selection of Mining Equipment
• Stripping Ratio – in case of Opencast.
• Life of the mine
• Infrastructure available
• Proposed annual output
• Technology available
21. Surface Miner
1. Selective mining.
2. Particularly suitable for coal having
compressive strength below 250 kg/cm2.
3. Suitable in gradient of 1 in 10 and flatter.
32. DRAGLINE
1. Gradients flatter than 1 in 6.
2. Seams should be free of faults & other
geological disturbances.
3. Deposits with Major Strike length.
4. A hilly property is not suitable.
5. Deposit should have atleast 15 years life.
48. LOAD HAUL DUMPER
Capacity – 2/2.7 Cu.M
Production – 150/200 Tonnes/day
For seams of 1 in 6 gradient and flatter
Thickness of 2.0 m to 4.0 m
49. SIDE DUMP LOADER
Capacity – 1.0 Cu.M
Production – 120 Tonnes/day
For seams of 1 in 5 gradient and flatter
Thickness of 2.0 m to 3.5 m
50. MECHANISED DRIVAGE MACHINES
Rate of drivage –6 meters/day
Production –150 Tonnes/day
For seams of 1 in 4 gradient and flatter
Thickness of 2.0 m to 4.0 m
51. Continuous Miner
Rate of drivage –50 meters/day
Production –1500 Tonnes/day
For seams of 1 in 5 gradient and flatter
Thickness of 3.0 m to 4.0 m
52. Mechanised Roof Bolter
Bolting -240 bolts/day
For seams of 1 in 5 gradient and flatter
Thickness of 2.0 m to 5.0 m
53. LONGWALL GENERAL LAYOUT
TOP Gate
FACE
Dip direction
Bottom
Gate
- Longwall mining method includes drivage of two long roadways in coal and joining them
at the end by a perpendicular drivage forming a face.
64. Punch Longwall
Advantages
• Step change in cost and productivity
• More production capacity
• High productivity & low cost
• Longer term and higher % of reserves extraction
• Easy logistics – near surface
• High gate road development rates feasible
• Higher and faster returns on investment
• Total investment ~ $100 million – compared with > $300
millions UG
72. Longwall Top Coal Caving (LTCC)
Technical Principle Of Top Caving
Rock stress 1st pressure Low stress Stress 2nd pressure Compact
peak abrupt drop peak stress
Pressure curve of top coalseam
Fracture
Virgin
5600
Coal Broken Coal
coal goaf
caving
2800
Working
Height
Front AFC Rear AFC
back
74. PED schematic operation
Antenna
(Surface or
Underground)
Link Data Link
PC for Modulator Transmitter
entering Ultra Low Frequency Transmission
messages. Through Rock
PED Receivers can be:
• BeltPED Personal Receiver (shown)
• AutoPED Vehicle Receiver
• ControlPED for Equipment Switching
• BlastPED for Remote Blast Initiation
