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The main fan operating point of a ventilation system is shown in the figure below. If an NPV of 200 Pa assists the ventilation system, the resultant pressure (Pa) and quantity (m<sup>3</sup>) generated by the<br><img src="/images/question-image/mining-engineering/mine-ventilation/1682429211-M2-3-73-95.PNG" title="Mine Ventilation mcq question image" alt="Mine Ventilation mcq question image">
A
500, 681
B
600, 63
C
640, 55
D
400, 63
E
640, 66
Correct Answer:
640, 66
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
The figure shows PV (pressure-volume) diagram of a mine ventilated by both natural means and an exhaust fan. The total ventilation energy is represented by
A
Area ABF + Area CDEF
B
Area ABRS + Area CDEF
C
Area ABRS + Area QDCR
D
Area ABF + Area QDCR
A fan running at a speed of 280 rpm circulates 105 m
3
/s of air in a mine. If the power input to the motor for driving the fan is recorded to be 75 kW, with the combined efficiency of fan and motor at 70%. If the fan pressure is to be increased by 200 Pa by changing the fan speed. the fan speed in rpm will become
A
768
B
549
C
392
D
332
The fan drift pressure readings and fan quantities are measured to be 500 Pa and 65 m
3
/s respectively at the time when NVP aids fan pressure. On reversal, the fan delivers a quantity of 50 m
3
/s while acting against NVP with fan drift pressure of 600 Pa. Assuming that the NVP remains constant in both cases the total resistance of the mine in Ns
2
/m
8
will be
A
0.9487
B
0.2750
C
0.4105
D
0.1635
Two splits A and B are ventilated from an intake airway. Resistances of the splits are 0.5 Ns
2
m
-8
and 0.8 Ns
2
m
-8
respectively. A regulator is placed in split B to maintain a flow of 15 m
3
/s and 10 m
3
/s in splits A and B respectively as shown in the figure. The size of the regulator in m
2
is
A
2.1
B
1.3
C
1.2
D
1.13
While measuring average air velocity of air flowing through a circular duct using precise traversing with equal area method, the radii r
1
, r
2
and r
3
, in mm, as shown in the figure of the three circles should be
A
83, 167 and 240
B
36, 107 and 261
C
102, 177 and 228
D
108, 157 and 216
Study the following information and answer the questions. Point A is 8m to the west of Point B. Point C is 4m to the south of Point B. Point D is 4m to the east of Point C. Point F is 6m to the north of Point D. Point E is 8m to the west of Point F. Point G is 2m to the south of Point E. How far and in which direction is Point G from Point A?
A
4m to the east
B
8m to the west
C
4m to the west
D
8m to the east
Study the following information and answer the questions. Point A is 8m to the west of Point B. Point C is 4m to the south of Point B. Point D is 4m to the east of Point C. Point F is 6m to the north of Point D. Point E is 8m to the west of Point F. Point G is 2m to the south of Point E. If point G is 4m to the north of Point H, then what is the distance between H and D?
A
11m
B
8m
C
6m
D
4m
A mine fan produces 30 m
3
/s of air at 240 Pa pressure running at 1400 rpm. If the fan speed is increased to 2100 rpm, the pressure in Pa and the quantity in m
3
/s generated by the fan will be
A
540 and 67.5
B
540 and 45.0
C
360 and 45.0
D
540 and 30.0
