Coal Mining — Part 1 MCQs with Explanations

Forced drop shaft method (also known as caisson sinking) is mainly used in conditions where there is heavy inflow of water into the shaft. In such strata, conventional shaft sinking becomes unsafe because continuous water ingress can collapse the sides and interrupt excavation . The method uses a heavy, watertight caisson that is gradually forced downward by its own weight while excavation proceeds inside it, ensuring stability and control over water entry . Although it can pass through bands of loose and tough strata , that is not the primary reason for its use . The most critical and defining condition for employing this method is heavy inrush of water , making Option C the correct answer .

100W is the correct answer to “The wattage of bulb in a cluster of each bulb”. This question is standard in competitive examination syllabi for Coal Mining.

1100 l is the correct answer to “The required water for 1 ton of sand in hydraulic sand stowing is . . . . . . . .”. This question is standard in competitive examination syllabi for Coal Mining.

Ventilation is the correct answer to “The purpose of pilot hole in stable pit drivage”. This question is standard in competitive examination syllabi for Coal Mining.

Under hung is the correct answer to “Scaffold not required in . . . . . . . . tubbing”. This question is standard in competitive examination syllabi for Coal Mining.

Moderate depth is the correct answer to “Bord and pillar method applied when a seam is”. This question is standard in competitive examination syllabi for Coal Mining.

Bhaska and Tipping is the correct answer to “The following method practiced in NECL (Assam) for extraction of steep thick seam.”. This question is standard in competitive examination syllabi for Coal Mining.

Hydraulic stowing is the correct answer to “Transportation of filled material with water to the worked out areas for filling called . . . . . . . .”. This question is standard in competitive examination syllabi for Coal Mining.

Inner tube is the correct answer to “In double tube core barrel which tube is non rotating”. This question is standard in competitive examination syllabi for Coal Mining.

Wall is the correct answer to “The face or working place which is parallel to main cleat is called . . . . . . . .”. This question is standard in competitive examination syllabi for Coal Mining.

900 is the correct answer to “With 3 or 4 stooks under extraction at a time, the total area should not exceed . . . . . . . . m 2”. This question is standard in competitive examination syllabi for Coal Mining.

More than 15m is the correct answer to “Horizontal slicing method applied if seam thickness is”. This question is standard in competitive examination syllabi for Coal Mining.

Freezing is the correct answer to “The type of sinking employed in unstable friable strata with heavy rush of water”. This question is standard in competitive examination syllabi for Coal Mining.

Inclined slicing in ascending order is the correct answer to “Seam thickness more than 8m and regular dip <60°, strong roof and floor, no self heating with easily cavable roof. Select best method.”. This question is standard in competitive examination syllabi for Coal Mining.

Dozer ptate is the correct answer to “The cut coal is loaded by . . . . . . . . In case of shear.”. This question is standard in competitive examination syllabi for Coal Mining.

Web is the correct answer to “The groove made by coal cutting machine is called”. This question is standard in competitive examination syllabi for Coal Mining.

25mm is the correct answer to “On the mixing cone, there is a screen to prevent pebbles larger than . . . . . . . . mm size from getting into shaft range with sand water mixing.”. This question is standard in competitive examination syllabi for Coal Mining.

1.2m is the correct answer to “Hangers placed at intervals of”. This question is standard in competitive examination syllabi for Coal Mining.

$$\frac{{440}}{{550V}}$$ is the correct answer to “The power available in under ground at a voltage of”. This question is standard in competitive examination syllabi for Coal Mining.

1000m is the correct answer to “The coal mining areas where the maximum drilling depth is upto”. This question is standard in competitive examination syllabi for Coal Mining.

DERD is the correct answer to “In longwall face cut by double back shuffle, can be only worked with”. This question is standard in competitive examination syllabi for Coal Mining.

Poetsch is the correct answer to “Freezing process of shaft sinking introduced by”. This question is standard in competitive examination syllabi for Coal Mining.

High carbon steel is the correct answer to “The stowing pipes in pneumatic stowing made of”. This question is standard in competitive examination syllabi for Coal Mining.

Step diagonal is the correct answer to “In which line of extraction one solid stook intervenes between two stooks under extraction at a time.”. This question is standard in competitive examination syllabi for Coal Mining.

4t is the correct answer to “OMS achieved by B. G method is more than . . . . . . . .”. This question is standard in competitive examination syllabi for Coal Mining.

30m is the correct answer to “Crane or grab used for clearing the debris upto a depth of . . . . . . . .”. This question is standard in competitive examination syllabi for Coal Mining.

Heading is the correct answer to “Gallery in the process of being driven”. This question is standard in competitive examination syllabi for Coal Mining.

Stable is the correct answer to “The extended portionof gate roads in L/W called”. This question is standard in competitive examination syllabi for Coal Mining.

1.5m is the correct answer to “The bord and pillar method adopted of the coal scam is thicker than . . . . . . . .”. This question is standard in competitive examination syllabi for Coal Mining.

4 is the correct answer to “The life of the M. S pipe used in sand stowing in lac ton of sand.”. This question is standard in competitive examination syllabi for Coal Mining.

25m is the correct answer to “Without derrick holes can be drilled depth of”. This question is standard in competitive examination syllabi for Coal Mining.

Rise is the correct answer to “Under ground gassification, development done towards”. This question is standard in competitive examination syllabi for Coal Mining.

30m is the correct answer to “Cable drilling employed commonly employed for holes deeper than”. This question is standard in competitive examination syllabi for Coal Mining.

Sequence controlled automatic machines is the correct answer to “In drilled shafts all the sinking work can be carried out by”. This question is standard in competitive examination syllabi for Coal Mining.

Borehole camera is the correct answer to “Continuous record of bore hole deviation from top to bottom by an instrument by”. This question is standard in competitive examination syllabi for Coal Mining.

1.8m is the correct answer to “While driving slices, what should be the minimum thickness of rib of coal to be left against adjacent goaf.”. This question is standard in competitive examination syllabi for Coal Mining.

100 L/min is the correct answer to “Pumps are employed when the make of water in the shaft exceed”. This question is standard in competitive examination syllabi for Coal Mining.

100 is the correct answer to “Common rate of sand stowing in μ/g mines is A tons of sand per hour. Value of A is given by . . . . . . . .”. This question is standard in competitive examination syllabi for Coal Mining.

Capacity of direct haulage is the correct answer to “The number of panels to be opened at a time decided by”. This question is standard in competitive examination syllabi for Coal Mining.

Suppression of dirt is the correct answer to “Water infusion of coal face in ploughing causes.”. This question is standard in competitive examination syllabi for Coal Mining.