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In an opencast mine shown in the figure below, the coal has a density of 1.4 t/m<sup>3</sup>. Assuming mining operation started from plane XY, the operating stripping ratio under the given conditions in m<sup>3</sup>/t is<br><img src="/images/question-image/mining-engineering/introduction-to-mining-engineering/1682335151-M2-1.3-8-25.PNG" title="Introduction to Mining Engineering mcq question image" alt="Introduction to Mining Engineering mcq question image">
A
2.32
B
2.47
C
2.56
D
2.64
Correct Answer:
2.56
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A pumping station in a mine has 4 pumps, P
1
, P
2
, P
3
and P
4
which are connected functionally in parallel configuration as shown in the figure. The individual reliability of the pumps P
1
, P
2
, P
3
and P
4
are 0.80, 0.90, 0.85 and 0.95 respectively. For an effective dewatering operation in the mine denoting system success, at least three pumps should be in operation. The reliability of the system is
A
0.19
B
0.93
C
0.99
D
0.58
Four mines A, B, C and D are located along a road as shown with production in Mt per year 1, 2, 1 and 3 respectively. In order to handle total coal produced. the ideal distance of a coal washery along the road from the mine A in Km is
A
4.01
B
3.91
C
3.81
D
3.71
A flat coal seam of thickness (t) 3m is excavated and broken roof rock has completely filled the space created due to extraction as shown in the figure. If the bulking factor of roof rock is 1.2. the caving height (H) in m is
A
15
B
16
C
14
D
12
A mine ventilation system consists of two splits A and B with resistances of 0.8 Ns
2
m
-8
and 3.2 Ns
2
m
-8
, respectively as shown in figure. Trunk airways have resistance of 0.2 Ns
2
m
-8
. The main mine fan is generating pressure of 500 Pa.
The flows in the two splits are equalized by placing a booster fan in split B. Assume that the fan pressure does not change after installation of the booster fan. The size of the booster fan in Pa is
A
749.05
B
850.08
C
950.02
D
1000.5
A mine ventilation system consists of two splits A and B with resistances of 0.8 Ns
2
m
-8
and 3.2 Ns
2
m
-8
, respectively as shown in figure. Trunk airways have resistance of 0.2 Ns
2
m
-8
. The main mine fan is generating pressure of 500 Pa.
The air quantities in m
3
/s circulated in the splits A and B respectively are
A
20 and 30
B
30 and 20
C
20 and 10
D
40 and 10
A bunker-conveyor system as shown in the figure works under the following scheme:
i. Bunker and two conveyors running
ii. Bunker and either of the two conveyors running
If the bunker and the two conveyors have identical reliability of 0.9. the system reliability is
A
0.729
B
0.810
C
0.999
D
0.891
The feasible region of an LP problem is shown as given below. The maximum value of the objective function Z = 1600X
1
+ 1200X
2
is
A
20400
B
20000
C
19200
D
16800
The individual reliability values of four sub-systems are given in the figure below. The reliability of the system is
A
0.42
B
0.22
C
0.61
D
0.52
A project network comprises five activities as shown below. The activity durations. in days. are as indicated. Crashing of any activity costs Rs. 1000 per day. If the project is crashed to the shortest possible duration without changing the critical path the total crashing coso in Rs. is
A
5000
B
4000
C
3000
D
2000
A two tonne mine car is released from the top of an incline at a height of 3m as shown in the figure. The mine car travels 45m along the inclined track and another 85m along the horizontal track before coming to rest. The specific rolling resistance of the, car in N/tonne is
A
0.226
B
0.326
C
0.526
D
0.126
