Introduction To Mining Engineering - Study Mode

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[#301] Ring pattern drill holes are provided in

(A) long wall mining

(B) bord and pillar mining

(C) blasting gallery

(D) widestall method

Correct Answer

(C) blasting gallery

[#302] What will happen if a Booster fan is placed too far inbye of the neutral point in either intake or return?

(A) a zone of leakage & recirculation will inevitably occur

(B) air velocity will increase

(C) air velocity will decrease significantly

(D) no change will take place

Correct Answer

(A) a zone of leakage & recirculation will inevitably occur

[#303] A developed panel for a coal seam having incubation period of 6 months has 32 square pillars under extraction having size 25 m and height 3.0 m. Density of coal is 1.4 tonne/m 3 . Extraction ratio during depillaring is expected to be 75%. To depillar the panel within the incubation period, assuming 25 working days in a month, the production from the panel in tonne/day is

(A) 420

(B) 480

(C) 560

(D) 680

Correct Answer

(C) 560

[#304] What should be the speed of air current when the wet bulb temperature exceeds 30.5°C?

(A) 0.5 m/sec

(B) 0.7 m/sec

(C) 0.8 m/sec

(D) 1 m/sec

Correct Answer

(D) 1 m/sec

[#305] A sample of 144 items gives a mean value of 45, with a standard deviation of 3. Calculate symmetric confidence limits within which the true population lies with 95% confidence?

(A) 41.5 and 42.5

(B) 42.5 and 43.5

(C) 43.0 and 43.5

(D) 44.5 and 45.5

Correct Answer

(D) 44.5 and 45.5