Mine Ventilation - Surface Environment, Mine Ventilation and Underground Hazards - Mining Engineering Previous Year Questions

1

2007 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2007

In a centrifugal flow fan the conversion of velocity pressure to static pressure is accomplished with the help of

A

impeller

B

curved blades

C

hub

D

casing

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2

2007 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2007

The most recent model of self-contained compressed-oxygen breathing apparatus is

A

Proto-IV

B

BG-174

C

BG-4

D

BG-174A

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3

2007 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2007

Two reservoirs are connected by two equal length parallel pipelines with diameters d and 2d. Assuming similar resistance coefficients, if the discharge through the smaller diameter pipeline is 0.04 m3/s, the discharge through the other pipeline in m3/s is

A

0.226

B

0.426

C

1.130

D

1.280

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4

2007 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2007

An air receiver of volume 0.2 m³ has an initial temperature of 27°C and pressure 1800 kPa. After use, the air pressure falls to 1200 kPa at a temperature of 17°C. The volume of air consumed in m³ corresponding to an air pressure of 101.3 kPa and temperature of 0°C is

A

0.693

B

0.895

C

1.002

D

1.251

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5

2007 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2007

A closed container with 10 kg of air at ambient pressure and specific heat 1020 kJ/kg °C is cooled from 35°C. If the removal of 200 kJ of heat resulted in the saturation of air, the corresponding dew point temperature in °C is

A

33.0

B

27.3

C

15.4

D

12.9

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6

2007 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2007

Identify the INCORRECT statement

A

Evasee is meant to minimise exit shock losses

B

Evasee efficiency is primarily a function of divergence angle and area ratio

C

Evasee produces an inevitable increase in friction losses

D

Evasee installation leads to reduction in the fan total pressure

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7

2007 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2007

A single lamp placed centrally at the roof provides 40 lux illumination vertically below, at the floor of an underground workshop. The workshop is of dimensions 20.0 m×20.0 m with height 4.0 m. Assuming uniform spherical dispersion of luminous intensity, the floor level illumination in lux at any corner of the workshop is

A

23.2

B

10.9

C

3.0

D

0.8

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8

2007 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2007

At a fan drift pressure of 450 Pa, 50 m³/s of air flows through a mine. When the fan stops, 10 m³/s of air still flows in the same direction. The mine resistance in Ns²/m⁸ is

A

0.1731

B

0.1800

C

0.1875

D

0.2372

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9

2007 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2007

The total pressure at the outlet of the duct is

A

-35.2

B

35.2

C

192.2

D

635.2

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10

2007 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2007

The total pressure at the inlet side of the fan is

A

-192.2

B

-150.0

C

150.0

D

192.2

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11

2007 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2007

The total pressure generated by the fan is

A

600.0

B

635.2

C

677.4

D

682.2

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12

2008 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2008

Q.12 Effective temperature is estimated from

A

Wet-bulb temperature, relative humidity, and air velocity

B

Dry-bulb temperature, relative humidity, and air velocity

C

Dry-bulb temperature, wet-bulb temperature, and air velocity

D

Dry-bulb temperature, wet-bulb temperature, and relative humidity

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13

2008 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2008

Q.13 Pressure-quantity characteristic of a mine fan is given below:
[Graph showing Pressure vs Quantity]
The combined characteristic of two such identical fans installed in parallel is

A

B

C

D

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14

2008 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2008

A roadheader district produces 20 mg/m³ of airborne dust with the following size distribution:

Size up to	Cumulative wt %
1 μm	1
5 μm	5
10 μm	10
20 μm	20
50 μm	50
> 50 μm	100

The concentration of respirable fraction of dust in mg/m³ is

A

0.2

B

2.0

C

10.0

D

1.0

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15

2008 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2008

For a person working in an atmosphere containing 21% O₂, the exhaled air contains 4.5% CO₂ and 16% O₂. The respiratory quotient of breathing is

A

0.21

B

0.9

C

0.28

D

1.11

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16

2008 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2008

A conveyor of rated power 100 kW hauls coal up-dip at 30 kg/s along an inclination of 15° and distance 300m. Heat added by the conveyor to the air in kW is

A

56.4

B

65.9

C

77.2

D

82.3

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17

2008 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2008

A cage of floor area 5.0 m² suspended in a shaft has a drag coefficient 2.5. If the velocity of air in the shaft is 6.0 m/s, the drag force (N) experienced by the cage is

A

120

B

170

C

200

D

270

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18

2008 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2008

Statement for Linked Answer Questions 82 and 83: In a mine ventilation system, the resistances of two splits A and B are 0.5 Ns²m⁻⁸ and 2.0 Ns²m⁻⁸ respectively. Combined resistance of two shafts and trunk airways is 0.7 Ns²m⁻⁸. A quantity of 20 m³/s of air passes through split A.

The total air quantity passing the mine in m³/s is

A

30

B

27

C

25

D

17

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19

2008 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2008

The total air power of the ventilation system in kW is

A

82.9

B

48.9

C

24.9

D

27.9

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20

2009 · Mining Engineering · Surface Environment, Mine Ventilation and Underground Hazards · Mine Ventilation

Mining Engineering (MN) 2009

Moody diagram represents resistance coefficient in terms of

A

Reynolds number and asperity ratio

B

viscosity and aspect ratio

C

surface tension and viscosity

D

Reynolds number and surface tension

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