Mining core
Mining Methods
5 self-contained study topics — notes, diagrams, formulas, and worked examples for exams and GATE.
Topics
- Surface Mining MethodsSurface mining economics hinge on stripping ratio SR = waste/ore — high SR demands dragline or truck-shovel optimisation. Bench height and slope angle φ must balance shovel reach, stability, and inter-ramp geotechnical limits.
- Underground Mining MethodsUnderground method selection depends on depth, dip, and orebody geometry — bord-and-pillar for flat coal seams, stoping for steep veins, longwall for continuous coal extraction. Extraction ratio and development metres per tonne ore measure efficiency.
- Drilling and BlastingDrilling and blasting design sets burden B, spacing S, and powder factor PF = explosive mass/rock mass to fragment rock safely and economically. Delay timing controls vibration; stemming length prevents gassing-off at collar.
- Strata ControlStrata control ensures pillars, supports, and roof bolts maintain FS = pillar strength / applied stress above unity. Empirical pillar strength formulas and abutment pressure concepts govern bord-and-pillar and longwall layouts in Indian coal mines.
- Mine Ventilation BasicsMine ventilation uses Atkinson's square law ΔP = RQ² to size fans and airways. Resistances add in series; parallel airways combine like conductances. Statutory minimum Q per person and per tonne diesel must be met in Indian mines.