Sum of the series 5, 10, 15,……., 500 is
Q. Sum of the series 5, 10, 15,…………………… , 500 is Sol:
gate questions
A 20 m long steel tape used for survey is found to be short by 10 cm
Q. A 20 m long steel tape used for survey is found to be short by 10 cm. If the area measured with the steel tape is 5000 m2, the actual area in m2 is . Ans: 4945.0-4955.0
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In a level terrain, a vertical orebody of 20 m uniform width is worked by surface mining
Q. In a level terrain, a vertical orebody of 20 m uniform width is worked by surface mining method. The density of the ore is 2.5 tonne/m3. The ultimate pit has a depth of 60 m, width of 20 m at pit bottom, and a pit slope of 45o. The overall stripping ratio for this
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The immediate roof of a mine is supported by bolts of length 1.5 m, arranged in 1.2 m
Q. The immediate roof of a mine is supported by bolts of length 1.5 m, arranged in 1.2 m x 1.2 m grid pattern. If the unit weight of roof rock is 2.25 tonne/m3 and load carrying capacity of each bolt is 7.5 tonne, the factor of safety of the support system is . Ans:
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In underground face blasting, the pull is found to be 10% less
Q. In underground face blasting, the pull is found to be 10% less than the drillhole length. The headings of 3.6 m width are supported by prop density of 1.44/m2. The hole length is 1.5 m, and 6 rounds of blasting are done in the panel per shift. The number of props to be erected
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The experiment to determine permeability of a soil sample is illustrated below
Q. The experiment to determine permeability of a soil sample is illustrated below. The cross- sectional area of the sample is 20.0 cm2. The permeability of the soil sample in cm/s is Ans: 0.02-0.02
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An SDL of 1.0 tonne capacity operates with a cycle time of 6 minutes
Q. An SDL of 1.0 tonne capacity operates with a cycle time of 6 minutes. The dimension of the face is 4 m x 3 m. Five blasts are conducted per shift with an average pull of 1.2 m. If the density of blasted coal is 0.8 tonne/m3, the time required by the SDL in
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In a direct rope haulage operating along a 1500 m long incline
Q. In a direct rope haulage operating along a 1500 m long incline, 180 tonne of coal is hauled in 7 hours. The average rope speed is 7.5 km/h. The set changing time for the tubs is 2 minutes each at the top and bottom of the incline. If the tub capacity is 1.0 tonne,
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Air enters a bord and pillar panel at 10 ppm CO and 20.78% O2
Q. Air enters a bord and pillar panel at 10 ppm CO and 20.78% O2. The air at the panel return has 80 ppm CO and 20.52% O2. The ‘Graham’s ratio’ for the status of fire in the panel in % is Ans: 2.65-2.75
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A person standing 50 m away from an HEMM experiences 90 dB sound pressure
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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