Questions 181–190 of 650. Imported answers require independent review unless marked reviewed.

Topic practice 650 questionsPage 19 of 65

Question 51

Open question
MNNAT2 marksNeeds review
Data for a centrifugal pump discharging water from a sump to the surface are given.
Head, m : 180 Discharge rate, m

/hr : 320 Operating hours per day for 270 days in a year : 14 Operating hours per day for remaining 95 days : 20 Overall efficiency of the pump system : 0.70 Specific weight of mine water, kN/m

: 10.20
The annual electrical power consumption in GWh, due to pumping operation, is _____. (round off up to 2 decimals)

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Question 52

Open question
MNNAT2 marksNeeds review
The root of the function,

in the interval [0, 1] using bisection method after two iterations, is _____. (round off up to 2 decimals)

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Question 53

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MNNAT2 marksNeeds review
A Bord and Pillar panel is developed at a depth of 250 m in a flat coal seam. The vertical stress gradient is 0.027 MPa/m. If the strength of a square pillar is 12.5 MPa, the extraction ratio of the pillar for a safety factor of 1.5, is _____. (round off up to 2 decimals)

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Question 54

Open question
MNNAT2 marksNeeds review
A Mohr-Coulomb envelop between shear stress,

and normal stress,

of a sandstone rock is given as

(unit of stress is MPa)
A sandstone sample is tested in triaxial mode with confining pressure of 5.0 MPa. The value of the shear stress,

in MPa at the failure, is_____. (round off up to 2 decimals)

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Question 55

Open question
MNNAT2 marksNeeds review
A circular tunnel is constructed at a depth of 100 m. The average unit weight of overburden rock is 27.0 kN/m

. If the tangential stress measured at point A located at the horizontal boundary of the tunnel as shown, is 5.0 MPa, the tangential stress at point B in MPa, is_____. (round off up to 2 decimals)
Diagram for Mining Engineering question 55


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Question 56

Open question
MNNAT2 marksNeeds review
A mine worker weighing (W) 600 N lifts an object of 100 N as shown. The 50% body weight is applied downward through point A and a force

is produced parallel to x axis by the contraction of erector spinae muscle during lifting. The lumber disc, L (shown by red box) acts as a smooth hinge and keeps the upper body in static equilibrium. Ignore all other forces in the body. The magnitude of the resultant of the reaction forces, in N at the lumber disc, is _____. (round off up to 2 decimals)
Diagram for Mining Engineering question 56


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Question 57

Open question
MNNAT2 marksNeeds review
A solid ball of mass 10 kg is subjected to forces as shown. The magnitude of the acceleration in m/s

, is _____. (round off up to 2 decimals)
Diagram for Mining Engineering question 57


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Question 58

Open question
MNNAT2 marksNeeds review
In an open pit mine, the mineral inventory, prices, costs and capacities are given.
Mineral inventory
Grade interval
Tonnage (in million tonne)
0 < Cu% ≤ 0.3
0
0.3 < Cu% ≤ 0.4
5
0.4 < Cu% ≤ 0.5
5
0.5 < Cu% ≤ 0.6
5
0.6 < Cu% ≤ 0.7
5
0.7 < Cu% ≤ 0.8
5
0.8 < Cu%
0
Concentrating cost : INR 3,200/tonne of ore milled Smelting & refinery cost : INR 10,000/tonne of copper metal Selling price : INR 6,50,000/tonne of copper metal Overall recovery : 100% Maximum production capacity : 5 million tonne/annum
The mine is operating at 5 million tonne in a year. Considering mine capacity being the only constraint, Lane’s algorithm (based on profit maximization) is used for determining mill cut-off grade. The total amount of copper produced in million tonne, in the life of the pit, is _____. (round off up to 2 decimals)

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Question 59

Open question
MNNAT2 marksNeeds review
A longitudinal section of a mined out stope block in a copper mine is shown by the shaded portion. For a uniform thickness of the stope block, the percentage of ore recovery is _____. (round off up to 2 decimals)
Diagram for Mining Engineering question 59


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Question 60

Open question
MNNAT2 marksNeeds review
The real rate of return from a mining project is 14%. If the inflation rate over the entire life of the mine is 5.5 %, then the nominal rate of return in %, is _____. (round off up to 2 decimals)

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