Professional Knowledge (Discipline-Specific)
Nature of the section
Professional Knowledge carries the largest weight and is entirely discipline-specific. Mining candidates should revise mining methods (bord and pillar, longwall, blasting gallery, continuous miner), strata control and roof support, ventilation and mine gases (methane, carbon monoxide, spontaneous heating), explosives and blasting practice, haulage and winding, drainage and pumping, mine surveying, and the statutory provisions of the Coal Mines Regulations and DGMS circulars. Electrical candidates need machines, power systems, protection, measurement and drives; Mechanical needs thermodynamics, fluid mechanics, strength of materials, production and machine design; Civil needs SOM, RCC and steel design, geotechnical engineering, surveying and hydraulics; Chemical needs mass transfer, reaction engineering and thermodynamics. Systems disciplines (Finance, HR, Marketing) get accounting and ratio analysis, labour law, and the marketing mix.
Traps
Questions turn on definitions and units rather than long calculation: head versus discharge in pump problems, gauge versus absolute pressure, nominal versus effective capacity, statute versus regulation. In ventilation, remember quantity Q = velocity × cross-sectional area; a unit slip is the most common scoring loss.
Worked example
An airway 2 m high and 3 m wide carries air at 1 m/s. Area = 6 m², so Q = 6 m³/s, i.e. 360 m³/min. State units at every step - mining numericals are marked on the unit as much as on the figure.
Rule of thumb: keep a one-page formula sheet per subject and revise statutory numbers separately, because they cannot be derived.