Q. A person standing 50 m away from an HEMM experiences 90 dB sound pressure level. If the person moves to a new location that is 70 m away from the HEMM, the sound pressure level experienced by the person, in dB, becomes _ Ans: 86.75-87.25 .
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Q. A panel in coal mine produces 400 tonne per day. The number of persons employed in each of the three shifts is 110, 130 and 120. As per CMR, the minimum quantity of air that needs to be circulated at the last ventilation connection of the panel in m3/min is (A) 780 (B) 900
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Q. A system of two identical components connected in series has reliability of 0.25. The reliability of each component is Ans: 0.5-0.5
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Q. In a bord and pillar development district, 6 headings driven along the strike direction are surrounded by panel barriers on the dip and rise sides. The maximum possible number of faces for the panel is Ans: 16.0-16.0
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Q. For the conveyor belt drive shown, the tension on the tight side (T1 ) is double that of the slack side. The coefficient of friction between belt and drum is 0.21. The minimum angle of lap (in degree) to avoid slippage of the belt is . Ans: 185.0-195.0
Q. The RL of the initial station is 200 m. If Σ BS = 1.54 m of the last station in m is and Σ FS = 0.45 m , then the RL. Ans: 201.09-201.09 .
Q. Two contours of RL 60 m and 70 m are separated by 34 m measured along dip of the seam. The dip of the seam in degree is Ans: 16.5-17.5
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Q. The figure depicts a transportation problem along with the solution. The correct statement is A. unbalanced problem, optimal solution B. unbalanced problem, sub-optimal solution C. balanced problem, optimal solution D. balanced problem, sub-optimal solution Ans: Balanced problem, optimal solution Sol: Total supply = 15+15 = 30 Total demand = 10+20=30 Total supply = Total
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Q. The property that CANNOT be determined from uniaxial compressive strength test of a rock sample fitted with strain gauges is (A) cohesion (B) Poisson’s ratio (C) modulus of elasticity (D) dilation Sol: cohesion
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Q. Exposure of weak roof in junctions of a development district in a coal mine can be decreased by(A) increasing dimension of panel barrier(B) stitching side walls(C) increasing support density at junctions(D) staggering the junctions Ans: staggering the junctions
