GATE MN topic:mining PYQs & Answers — Page 25

Questions 241–250 of 650. Imported answers require independent review unless marked reviewed.

Topic practice 650 questionsPage 25 of 65

A continuous miner served by two shuttle cars produces 240 tonne/hr. The capacity of each shuttle car is 10 tonne. When a single shuttle car operates, the cycle time becomes 4 min. In case one of the shuttle cars is under break-down, the reduction in hourly production from that of two cars in percent is _____.

[rounded off to 1 decimal place]

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A circular tunnel is developed in a biaxial in situ stress field as shown in the figure. If the ratio between tangential stress at the boundary point A and that at the boundary point B is 2.0, the value of k is _____.

[rounded off to 2 decimal places]

Diagram for Mining Engineering question 47

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Strength of a rectangular coal pillar in MPa is given by

where

(

) and

are width, length and height of the pillar, respectively. The parameter

is constant.

A 30 m square pillar is split into two halves as shown in the figure. The height of the pillar is 3 m. The ratio of safe factors between one half-pillar and the original square pillar is _____.

[rounded off to 2 decimal places]

Diagram for Mining Engineering question 48

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A dozer pushes up a 100 kg spool of cable along a 20° incline road at a constant velocity as shown in the figure. The coefficient of static friction between the dozer bucket and the spool (Point B) is 0.45, and coefficient of kinetic friction between road and the spool (Point A) is 0.15.

Consider the spool only slides up the incline. The maximum normal force in N acting at Point B, is _____.

[rounded off to 1 decimal place]

Diagram for Mining Engineering question 49

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Stress waves are sent from the transmitter A to the receiver B through an isotropic and elastic cylindrical rock specimen as shown in the figure.

The length of the specimen is 100 mm. The travel time of longitudinal and shear waves are 0.025 ms and 0.04 ms, respectively. The Poisson’s ratio of the rock specimen is _____.

[rounded off to 2 decimal places]

Diagram for Mining Engineering question 50

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A jointed rock sample is subjected to 20 MPa vertical stress as shown in the figure.

The modulus of elasticity of the rock is 10 GPa and the normal stiffness of the joint surface is 5 GPa/m. Assuming one-dimensional elastic behavior of rock and joint, the displacement in mm of the loading surface AB is _____.

[rounded off to 1 decimal place]

Diagram for Mining Engineering question 51

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An unmanned aerial vehicle (UAV) with payload of 2 kg reaches vertically 100 m in 10 s at uniform velocity. The self-weight of the UAV is 1.2 kg. The power required in lifting in kW is _____.

[rounded off to 2 decimal places]

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An irregular shaped rock sample of mass 60 g displaces 27 g of brine when submerged in a filled jar. The specific gravity of brine is 1.05. The unit weight of the rock sample in kN/m³ is _____.

[rounded off to 2 decimal places]

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The reliability function of a pump is given as

, where t stands for time in years. If the pump comes with a six-month warranty, the number of years for the pump to attain a reliability of 0.9 is _____.

[rounded off to 2 decimal places]

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In a sample of groundwater, the concentration of Ca²⁺ is 200 mg/l. The corresponding calcium carbonate hardness in mg/l is _____.

[rounded off to 1 decimal place]

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GATE MN topic:mining PYQs

Question 46

Question 47

Question 48

Question 49

Question 50

Question 51

Question 52

Question 53

Question 54

Question 55