Mine Ventilation MCQs Questions & Answers | Mining Engineering Page-6 section-1

51.
For the same roadway roughness, area, length and velocity condition the ratio of resistances of a square roadway to that of a rectangular roadway having width and height ratio. 2 : 1 is

A. $$\frac{1}{{\sqrt 3 }}$$

B. $$\frac{{2\sqrt 2 }}{3}$$

C. $$\frac{{3\sqrt 2 }}{2}$$

D. $$\frac{{\sqrt 2 }}{3}$$

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52.
The mean velocity of air current through an airway of 9m² cross-sectional area is found to be 1.5 m/s, If the mean methane content of air current is 0.6%, the layering index will be

A. 3.10

B. 2.71

C. 2.15

D. 1.80

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53.
Air at dry bulb temperature of 27°C enters a 1200 m deep shaft. The specific heat of air-water vapour mixture is 1.03 KJ/kg °C. If the air goes through constant-moisture adiabatic auto compression, the air temperature at the bottom of the shaft in °C is

A. 11.4

B. 33.1

C. 35.4

D. 38.4

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54.
The blade tip speed of a backward bladed centrifugal fan running at 300 rpm delivers 120 m³/s of air. If the tip speed of the blade is 47.12 m/s and width of the fan is 1.3 m then the radial velocity of air at the periphery of the impeller in m/s is

A. 9.79

B. 12.73

C. 30.79

D. 40.22

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55.
An underground coal mine panel produces 520 tonnes per day deploying 220, 200 and 192 persons in three shifts. As per CMR 1957, the minimum quantity of air in m³/min to be delivered at the last ventilation connection of the panel is

A. 1120

B. 1320

C. 1220

D. 1550

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56.
The formula for finding the velocity of air . . . . . . . .

A. $$4.015\sqrt {wg} $$

B. $$3\sqrt {wg} $$

C. $$4.8\sqrt {wg} $$

D. $$6\sqrt {wg} $$

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57.
Match the following:

Mine gas Principal constituent

P. Stink damp 1. CO

Q. White damp 2. H₂S

R. Black damp 3. CH₄

S. Fire damp 4. CO₂

A. P-1, Q-2, R-3, S-4

B. P-3, Q-4, R-1, S-2

C. P-2, Q-1, R-4, S-3

D. P-2, Q-1, R-3, S-4

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58.
The lower and upper limit of methane - air explosive mixture is

A. 0.75%, 1.25%

B. 5.4%, 14.8%

C. 5.0%, 15.0%

D. 5.9%, 12.5%

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59.
The sp.gr of CO₂

A. 1.2

B. 1.52

C. 0.553

D. 0.967

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60.
In a mine between upcast shaft and downcast shaft, two airways are connected in parallel and their resistances are 100 and 120 Ns^-2m^-8 respectively. The resistance of upcast shaft, downcast shaft and the fan drifts are 10, 20, and 5 Ns^-2m^-8 respectively. The rate of airflow through the split airway having resistance of 100 Ns^-2m^-8 in m³/s is

A. 0.42

B. 0.79

C. 2.19

D. 7.90

E. 270.06

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Mine gas	Principal constituent
P. Stink damp	1. CO
Q. White damp	2. H₂S
R. Black damp	3. CH₄
S. Fire damp	4. CO₂

Mine Ventilation MCQs Questions & Answers | Mining Engineering

51. For the same roadway roughness, area, length and velocity condition the ratio of resistances of a square roadway to that of a rectangular roadway having width and height ratio. 2 : 1 is

Answer & Solution

52. The mean velocity of air current through an airway of 9m2 cross-sectional area is found to be 1.5 m/s, If the mean methane content of air current is 0.6%, the layering index will be

Answer & Solution

53. Air at dry bulb temperature of 27°C enters a 1200 m deep shaft. The specific heat of air-water vapour mixture is 1.03 KJ/kg °C. If the air goes through constant-moisture adiabatic auto compression, the air temperature at the bottom of the shaft in °C is

Answer & Solution

54. The blade tip speed of a backward bladed centrifugal fan running at 300 rpm delivers 120 m3/s of air. If the tip speed of the blade is 47.12 m/s and width of the fan is 1.3 m then the radial velocity of air at the periphery of the impeller in m/s is

Answer & Solution

55. An underground coal mine panel produces 520 tonnes per day deploying 220, 200 and 192 persons in three shifts. As per CMR 1957, the minimum quantity of air in m3/min to be delivered at the last ventilation connection of the panel is

Answer & Solution

56. The formula for finding the velocity of air . . . . . . . .

Answer & Solution

57. Match the following: Mine gas Principal constituent P. Stink damp 1. CO Q. White damp 2. H2S R. Black damp 3. CH4 S. Fire damp 4. CO2

Answer & Solution

58. The lower and upper limit of methane - air explosive mixture is

Answer & Solution

59. The sp.gr of CO2

Answer & Solution

Answer & Solution

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51.
For the same roadway roughness, area, length and velocity condition the ratio of resistances of a square roadway to that of a rectangular roadway having width and height ratio. 2 : 1 is

52.
The mean velocity of air current through an airway of 9m² cross-sectional area is found to be 1.5 m/s, If the mean methane content of air current is 0.6%, the layering index will be

53.
Air at dry bulb temperature of 27°C enters a 1200 m deep shaft. The specific heat of air-water vapour mixture is 1.03 KJ/kg °C. If the air goes through constant-moisture adiabatic auto compression, the air temperature at the bottom of the shaft in °C is

54.
The blade tip speed of a backward bladed centrifugal fan running at 300 rpm delivers 120 m³/s of air. If the tip speed of the blade is 47.12 m/s and width of the fan is 1.3 m then the radial velocity of air at the periphery of the impeller in m/s is

55.
An underground coal mine panel produces 520 tonnes per day deploying 220, 200 and 192 persons in three shifts. As per CMR 1957, the minimum quantity of air in m³/min to be delivered at the last ventilation connection of the panel is

56.
The formula for finding the velocity of air . . . . . . . .

57.
Match the following:

Mine gas Principal constituent

P. Stink damp 1. CO

Q. White damp 2. H₂S

R. Black damp 3. CH₄

S. Fire damp 4. CO₂

58.
The lower and upper limit of methane - air explosive mixture is

59.
The sp.gr of CO₂