The document discusses various underground mining methods. Room-and-pillar mining involves drilling, blasting, loading, hauling, scaling, and bolting to extract ore while leaving pillars of untouched material to support the mine roof. It can be used for deposits with different dips and thicknesses. Room-and-pillar mining may later involve caving of pillars to extract residual ore. Longwall mining uses a longwall shearer to continuously mine coal or ore in a long panel, allowing the newly mined area to cave in a controlled manner behind hydraulic roof supports. It can also involve backfilling or back timbering for additional ground support.

1. Underground Mining Methods

2. Ore body elements dip Width,thickness hanging wall footwall overburden horizontal exetend Vertical extent

3. Ore body geometry Seam or flat dipping vein Steeply dipping vein Massive deposit Dip < 10 ° Thickness is much less than horizontal extend Medium dipping vein Dip > 45 - 50° Thickness is much less than horizontal and vertical extend 10° < Dip < 45° Thickness is much less than horizontal and vertical extend Horizontals and vertical extends are equal

4. Room-and-pillar mining Drilling and blasting Loading and haulage Scaling and Bolting

5. Room-and-pillar mining Drilling Rig LHD Truck Bolting Rig Scaling Machine Ventilation Drift Pillars Rib Pillar Transport Drift Stope Drift Room Room Room

6. Room-and-pillar mining Mechanized room-and-pillar mining of a thick ore body Non mechanized room-and-pillar mining of an inclined ore body

7. Room-and-pillar mining Mechanized room-and-pillar step mining of an inclined ore body

8. Room-and-pillar m echanized multiple-passe mining Mechanized multiple-passe mining

9. Room-and-pillar mining with caving of pillars Primary extraction Primary extraction Primary extraction Secondary extraction Caving of residual pillars Recoverable pillar Residual pillars

10. Room-and-pillar mining with caving

11. Room-and-pillar mining with caving

12. Room-and-pillar mining with backfilling Backfilling with cemented fill Primary extraction Secondary extraction Filling of secondary opening with cemented fill Tertiary extraction Filling of tertiary openings with non cemented fill

13. Post-pillar mining of thick layers or massive deposits

14. Longwall mining with caving

15. Longwall mining with caving

16. Longwall multiple slicing with caving 2 slice 3 slice 5 slice 4 slice caved 1 slice

17. Longwall mining with backfilling

18. Longwall mining with backfilling Cooper mine Mansfelde (German) 1, 3 - transport drifts ; 2 - stope drifts ; 4 - crosscuts

19. Longwall mining with back timbering Support by timbers Support by wood packs

20. Longwall mining with back timbering

21. Longwall mining with back timbering

22. Longwall mining with caving with backfilling with back timbering

23. Post-pillar mining of thick layers or massive deposits