Mining Methods5th December 2008VENKAT M. PlotMakerTeam Lead – Minex, INDIA
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 worlds coal production is coming from Opencast mines.• This scenario is same in India also.
DRAGLINE1. 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.
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
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
MECHANISED DRIVAGE MACHINESRate of drivage –6 meters/dayProduction –150 Tonnes/dayFor seams of 1 in 4 gradient and flatterThickness of 2.0 m to 4.0 m
Continuous MinerRate of drivage –50 meters/dayProduction –1500 Tonnes/dayFor seams of 1 in 5 gradient and flatterThickness of 3.0 m to 4.0 m
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
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.
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
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
PED schematic operation Antenna (Surface or Underground) Link Data Link PC for Modulator Transmitterentering Ultra Low Frequency Transmissionmessages. Through Rock PED Receivers can be: • BeltPED Personal Receiver (shown) • AutoPED Vehicle Receiver • ControlPED for Equipment Switching • BlastPED for Remote Blast Initiation