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FCU-MINE VENTILATION DGMS EXAM-2021

Question Paper _ Key of DGMS FIRST CLASS UNRESTRICTED UNDER CMR - MINE VENTILATION

1)      Air samples collected from the intake and the return gates of a retreating long wall face show methane concentration values of 0.1 percent and 0.9 percent respectively. The production from the long wall face is 2000 tonne/day and the air quantity circulating the face is 15 m3/s. The rate of methane emission in m3 per tonne of coal produced is

A)     5.18

B)     4.52

C)     11

D)     6.21

E)     9.52

 

2)      What is the pressure required to circulate 20 m3/s of air through a mine airway of 400 m long, 3 m high & 3 m wide ? (The co-efficient of friction of the airway is 0.01 Ns2/m4).

A)     26.33 Pa

B)     28.34 pa

C)     24.32 Pa

D)     27.97 Pa

E)     22.31 Pa

 

3)      According to general rules that governs the erection of water barriers, the distance between water barriers must not exceed -------------m in gate roads and not exceed   m in main roads.

A)     20;50

B)     300 ; 500

C)     100 ; 200

D)     200 ; 400

E)     500 ; 600

 

4)      One Murg is equal to     Ns2/m8.

A)     None of the above

B)     0.00981

C)     9.81

D)     0.0981

E)     0.981

 

5)      Determine the useful cooling effect or evaporator duty, if water mass flow rate is 60 litres/second, Sp. Heat of water is 4187 J/kgoC and temperature drop of water is 10 degree centigrade.

A)     2242.4 Kw

B)     2512.2 kW

C)     2864.2 kW

D)     2456.2 kW

E)     2658.8 kW

 

6)      20 m3/s of air flow through a long wall panel having 1000 tonnes per day production. Between the intake and return of the panel, the fire damp increases from 0 to 0.2 percent. Find the Rate of the fire damp emission.

A)     3.75 m3/t

B)     3.65 m3/t

C)     2.45 m3/t

D)     3.45 m3/t

E)     3.15 m3/t

 

7)      The evasee inlet air velocity is 10 m/s and the evasee outlet air velocity is 4 m/s. Find out the pressure gain in evasee, if the density of air is 1.2 kg/m3.

A)     56.4 Pa

B)     54.6 Pa

C)     58.4 Pa

D)     50.4 Pa

E)     60.4 pa

 

8)      Match the following with respect to physiological effects of CO2

         percent of CO2 in air                             Effects

         A. 0.5                                          1. Violent panting leading to fatigue from exhaustion, headche

         B. 3.0                                          2. Lung ventilation increased by 50 percent

         C. 2.0                                         3. Lung vetilation doubled, panting on exertion

         D. 5 to 10                                   4. Lung ventilation increased by 5percent

         E. 10 to 15                                 5. Intolerable panting, severe headche, rapid exhaustion & collapse

A)     A-4, B-3, C-2, D-1, E-5

B)     A-5, B-4, C-2, D-1, E-3

C)     A-4, B-5, C-2, D-1, E-3

D)     A-5, B-4, C-2, D-3, E-1

E)     A-1, B-4, C-2, D-5, E-3

 

9)      Match the following;

         Rock                               Thermal conductivity,( kJ m-1 s-1K-1)X10-4

         A. Shale                         1. 3.56-4.61

         B. Broken shale             2. 2.6

         C. coal                            3. 7.95-19.26

         D. sand                           4. 1.88

                                                5. 2.2  

A)     D-3,A-1,B-4,C-2

B)     D-1,A-5,B-3,C-4

C)     D-1,C-5,B-3,A-4

D)     D-2,A-3,B-4,C-1

E)     B-4,A-3,D-1,C-2

 

10)    What percentage (aproximately) of total heat added to the air in coal mines is attributed to oxidation of coal ?

A)     50-55percent

B)     60-65percent

C)     65-70percent

D)     55-60percent

E)     80-85percent

 

11)    The production of dust shall be reduced by using bits which are ------ and of proper  --.

A)     sharp, shape

B)     hard tipped, size

C)     tungsten tipped, size

D)     of good quality, design

E)     tough, design

 

12)    Two identical fans each produce the same total water gauge when placed in series as when they are run separately, then the quantity produced in series combination will be the quantity produced by one of them.

A)     √3 times

B)     √2 times

C)     √1.5 times

D)     √2/3 times

E)     √1/2 times

 

13)    Density of air (mass per unit volume) varies with its -----------, pressure and      content.

A)     absolute temperature, vapour

B)     temperature, moisture

C)     temperature, oxygen

D)     humidity, sp.heat

E)     temperature, Nitrogen

 

14)    An air-path has resistance of 0.1 gaul. Another path of same resistance is added in series. The air quantity flowing through these two paths is 600 m³/min. The pressure of ………. Pa will be developed between the start & end of these two paths.

A)     20

B)     36

C)     None of these

D)     50

E)     10

 

15)    As per statute, where electric lighting is used, an additional light or lamp having no connection with electric supply shall be kept continuously burning at which of the following place (s) ?

A)     in travelling roadway

B)     in haulage roadway

C)     every engine room & in travelling roadway

D)     every engine room, in haulage roadway & in travelling roadway

E)     every engine room

 

16)    Identify the CORRECT statement or statements : Mine climate :-

Statement (1): The thermal diffusivity (d) of a rock is given by the relation : d=k/Cp , where k= thermal conductivity of the rock, C= Specific heat of the rock and p= density of the rock.

Statement (2): The thermal diffusivity (d) of a rock ia given by the relation : d=kC/p , where k= thermal conductivity of the rock, C= Specific heat of the rock and p= density of the rock.

Statement (3): Coefficient of thermal conductivity(k) is given the equation, q=k At. Dt/l, where q= amount of heat flowing, A=area,t= time,Dt= temperature difference and l= thickness of material.

Statement (4): For rocks , the co-efficient of thermal conductivity depends to a large extent on the pore space, the more porous rocks having less thermal conductivity.

A)     Statement (1), (3) & (4) only

B)     Statement (2) & (4) only

C)     Statement (2), (3) & (4) only

D)     Statement (1) & (4) only

E)     Statement (1), (2) & (3) only

 

17)    In case of First or Second Degree gassy mines, air velocity at 7.5 m outbye of the discharge end of an air pipe shall not be less than   metres/ minute.

A)     45 m/min

B)     25 m/ min

C)     30 m/min

D)     35 m/min

E)     15 m/min

 

18)    Match the following - with respect to apparatus / equipments to be kept at a Rescue Station.

            Rescue apparatus/equipments                                   Numbers or metres

            P. Breathing apparatus - absorbent charges                         1. 60

            Q. Guide line in metres                                                           2. 300

            R. Fire fighting -hose pipe in metres                                      3. 1000

            S. Safety helmets                                                                    4. 2000

A)     P-4,Q-3, R-1, S-2

B)     P-4,Q-2, R-3, S-1

C)     P-4,Q-3, R-2, S-1

D)     P-3,Q-4, R-2, S-1

E)     P-1,Q-3, R-2, S-4

 

19)    When in any mine if it is intended to construct a Reservoir, Dam or other structure to withstand pressure of water or other liquid matter that is likely to flow when wet, which of the following statements is correct:

A)     Permission is to be obtained form Regional inspector of mines

B)     Prior Notice of 14 days shall be sent to Regional inspector of mines.

C)     Notice shall be sent to Chief Inspector of Mines

D)     Notice shall be sent to Regional inspector of Mines within 14 days of completion of construction

E)     Permission is to be obtained from Chief Inspector of Mines

 

20)    Match the following;

            Rock                            Thermal diffusivity,( m2s-1X10-7 )

         A. Shale                                     1. 2.4

         B. Broken shale                         2. 2.2-2.8

         C. coal                                        3. 5.95-9.26

         D. sand                                       4. 3.3

                                                            5. 4.0-9.6        

A)     D-1,A-5,B-3,C-4

B)     D-3,A-1,B-4,C-2

C)     D-2,A-3,B-4,C-1

D)     B-4,A-3,D-1,C-2

E)     D-1,C-2,B-4,A-5

 

21)    Find the Quantity of air to be circulated to u/g workings where 150 persons are employed in a largest shift and daily production of coal is 600 tonnes.

A)     900 m3/min

B)     1500 m3/min

C)     900 m3/sec

D)     1250 m3/min

E)     1500 m3/s

 

22)    Although SO2 gas is colourless, ----- fumes may be seen due to condensation of acidic water vapours or traces of ---

A)     black, sulphuric acid (H2SO4)

B)     brown, ionic sulphate

C)     purple, hydrogen sulphate

D)     white, sulpher trioxide (SO3)

E)     None of the above

 

23)    In case of coal seams containing more than 30 percent of volatile matter (on dry ash free basis) , the fine incombustible dust used for treatment in underground workings shall always consists of a mixture containing at least how much percent of incombustible matter ?

A)     95percent

B)     None of the above

C)     65percent

D)     75percent

E)     85percent

 

24)    As per the statute, the screening or sorting plant of coal shall be placed at what distance from the top of downcast shaft or mine intake airway, as far as practicable ?

A)     Not within 70 m

B)     Not within 50 m

C)     None of the above

D)     Not within 60 m

E)     Not within 30 m

 

25)    What is the purpose of using caustic soda in Gas mask ?

A)     To remove ammonia and water vapour

B)     To remove dust and smoke

C)     Converts CO to CO2

D)     To remove sulphuretted hydrogen

E)     To regenerate oxygen

 


 

27)    From a coal seam in mine 1000 t per day is being produced. The coal seam has inflammable gas emmission rate of 15000 cubic meter per day. Percentage of methane in general body of air is 0.15. The gassiness of the seam is

A)     Degree III

B)     data insufficient

C)     Degree II

D)     Degree I

E)     Degree IV

 

28)    A given volume of moist air is   same volume of dry air.

A)     either equal to or heavier than

B)     lighter than

C)     heavier than

D)     either equal to or lighter than

E)     equal to

 

29)    A fan is running at 850 rpm and passing air of inlet density of 1.2 kg/m3. The pressure developed by the fan is 2.2 kPa. Calculate the corresponding new pressure, if the fan is run at 1000 rpm in air of density 1.1 kg/m3.

A)     3.97 kPa

B)     3.57 kPa

C)     4.12 kPa

D)     3.87 kPa

E)     2.79 kPa

 

30)    Identify the INCORRECT statement or statements with respect to prevention of liberation, accumulation and propogation of airborne dust -

Statement (1): Dust shall be suppressed as close as possible to its source of formation.

Statement (2): During drilling sharp bits of proper shape shall be used.

Statement (3): During drilling suitable pressure shall be applied on the bits and the holes shall be kept clear of the cuttings.

A)     Statement (2) only

B)     Statement (3) only

C)     Statement (1) only

D)     Statement (1) & (2) only

E)     None of the Statement

 

31)    A vertical shaft 6m in diameter is connnected at its bottom level plat 4.5 x 2.5 m in cross-section. The flow of air in the shaft is 180 m3/s. Calculate velocity of air in the shaft and velocity of air in the plat.

A)     6.36 m/s and 16 m/s

B)     6.86 m/s and 16.6 m/s

C)     6.96 m/s and 16.9 m/s

D)     6.66 m/s and 16.2 m/s

E)     6.56 m/s and 16.4 m/s

 

32)    What will be the required power input to a fan motor installed to circulate 1800 m³/min. of air through a mine airway maintaning the required air pressure is 1 kPa, if the fan efficiency and fan motor efficiency are 80percent and 90percent respectively ?

A)     69 kW

B)     22.3 kW

C)     55.2 kW

D)     36.6 kW

E)     41.7 kW

 

33)    Axial-flow fans are machines with         capacity,          head and   specific speed.

A)     low, high , very low

B)     high, high, high

C)     low, low, low

D)     None of the above

E)     high, low, very high

 

34)    Identify the CORRECT statement or statements with respect to Carbon dioxide gas.

Statement (1): Water at 293 K absorbs 0.88 times its own volume of carbon dioxide forming carbonic acid.

Statement (2): The solubility of Carbon dioxide in water decreases with decrease in temperature of water.

Statement (3):  Cabon dioxide has mildly toxic physiological effect.

 A)    Statement (2) only

B)     Statement (1) & (3) only

C)     Statement (1) only

D)     All the statements

E)     Statement (1) & (2) only

 

35)    A sample of return air from a district shows the following gas percentage O2-20.20, CO-0.003, CO2-0.32, CH4- 0.74 and N2-78.74 , Calculate CO2 produced/Oxygen absorbed ratio, when intake air contains 20.93percent O2, 79.04 N2 and 0.03 CO2 .

A)     43.70percent

B)     42.30percent

C)     41.70percent

D)     44.60percent

E)     41.50percent

 

36)    The following sample was taken in the return of a suspisious fire Area. Find out the Graham's Ratio to understand the status. CO2-3.5percent, O2-13.36percent, N2-81.45percent , CO-0.09 percent, CH4- 1.6 percent. (The combination of Intake air is assumed to be O2- 20.93percent, N2-79.04percent & CO2- 0.03percent).

A)     1.4

B)     1.9

C)     1.1

D)     1.6

E)     2.8

 

37)    Profilometer is used for measuring       --.

A)     Cross section of irregular shape

B)     Air velocity

C)     Pressure of the air

D)     percent of CH4

E)     Roughness of airway

 

38)    Which of the following is an advantage of axial flow fan ?

A)     Quantity controllable by varying the pitch of the plates

B)     Requires less space for installation

C)     Smaller and cheaper foundation

D)     Reversal easier by reversal switch

E)     All the above

 

39)    Heat by men is produced in the mine through the process of  --.

A)     None of the above

B)     Exhalation

C)     Radiation

D)     Oxidation

E)     Metabolism

 

41)    What is the minimum level of illumination required to be provided (in Lux) at undeground Electrical substation, in Indian coal mines ?

A)     75 H, 50 V

B)     50 H, 25 V

C)     75 H, 40 V

D)     100 H, 50 V

E)     50 H, 30 V

 

42)    Identify the CORRECT statement/statements with regard to occasions when reversal of fan is usually resorted to.

Statement (1): When it is desired to reach an underground fire without having to pass through the smoke. Statement (2): When it is desired to choke a fire with its smoke.

Statement (3): When the fire occurs at the bottom of upcast shaft, or in the main return airway.

A)     Statement (1) & (2) only

B)     Statement (2) only

C)     Statement (1) & (3) only

D)     Statement (3) only

E)     Statement (1) only

 

43)    A wet drill drilling at a drift face produces a dust concentration of 400 particles per cubic centimetre in the respirable size range, while dust concentration rises to 700 particles per cubic centimetre if the drilling is done dry. Calculate the amount of dust of respirable size produced per minute in wet & dry drilling, if the drift face is ventilated by a tube delivering 2.5m3s-1 of fresh air.

A)     6x1010 particles & 10.5 x 1010 particles

B)     5x1010 particles & 8.6 x 1010 particles

C)     7x1010 particles & 9.65 x 1010 particles

D)     7.8x1010 particles & 11.5 x 1010 particles

E)     8.5x1010 particles & 12.8 x 1010 particles

 

44)    A total aggregate quantity of air amounting to 1000 cubic metre per minute is passing through two airways of same uniform shape and cross-sectional dimensions throughout their length connected at both ends. The length of one of these airways is 500m and that of the other 1000m. How much air is passing through the shorter airway ?

A)     585.8 m3/m

B)     500 m3/m

C)     625.5 m3/m

D)     550 m3/m

E)     752.5 m3/m

 

45)    An insidious effect of Nitrogen dioxide poisioning is that an apparent early recovery can be followed, soon afterwards, by development of  --.

A)     brain stroke

B)     nervous breakdown

C)     severe depression

D)     coma & depressed pulse

E)     bronchopneumonia

 

46)    Choose the correct statement(s) ?

(a)     Combination of fans in series is opted to meet pressure requirement.

(b)     Combination of fans in series is opted to meet quantity requirement.

(c)     Combination of parallel fans is opted to meet pressure requirement.

(d)     Combination of parallel fans is opted to meet quantity requirement.

A)     Both (b) & (c)

B)     (c) only

C)     (a) only

D)     (b) only

E)     Both (a) and (d)

 

 

47)    Water gas is formed by passing ---------- over heated  -- .

A)     air, water

B)     carbon monoxide, surface

C)     water , iron

D)     None of the above

E)     steam, hydrocarbons

 

48)    The production rate from a longwall face is 1856.25 t/day. The methane gas emission is 16 m3/t, the working hours per day is 18. Find out the methane gas emission rate at the given production rate.

A)     0.52 m3/s

B)     0.42 m3/s

C)     0.46 m3/s

D)     0.39 m3/s

E)     0.49 m3/s

 

49)    The quantity of moisture present in air is chiefly dependent on ---------- and   , other things being equal.

A)     temperature, velocity

B)     temperature, pressure

C)     temperature, volume

D)     cooling power, area

E)     barometric pressure, air density

 

50)    Identify the CORRECT statement/statements regarding air flow through mine openings:

Statement (1): Flow of air in mine airways is always laminar.

Statement (2): The frictional pressure loss is proportional to the square of the velocity of air. Statement (3): Flow of air as a result of leakage of air through goaf or loose waste rock is laminar.

A)     Statement (2) & (3) only

B)     Statement (1) & (2) only

C)     Statement (1) & (3) only

D)     Statement (3) only

E)     Statement (2) only

 

51)    In order to increase the effectiveness of fan, it is, necessary to transform the ---------- into          , before allowing air to pass into the surrounding atmosphere.

A)     pressure energy , kinetic energy

B)     None of the above

C)     pressure energy , potential energy

D)     heat energy, useful energy

E)     kinetic energy, pressure energey

 

52)    If in the mine the gas emitted is a mixture of 80percent methane, 10percent hydrogen, 10percent ethane, then the lower explosibility limit of this gas mixture will be   (Assume : LEL of methane=5percent, LEL of Hydrogen = 4.1percent & LEL of Ethane = 3.2percent):

A)     4.99percent

B)     4.86percent

C)     4.60percent

D)     4.98percent

E)     4.96percent

 

53)    If sum of the powers developed by the fans is to be the same when running in series as when running separately, the quantity will increase the quantity produced by one of them.

A)     √2/3 times

B)     3√2 times

C)     √1.5 times

D)     √1/2 times

E)     √3 times

 

54)    Identify the INCORRECT statement or statements with respect to the dust plan required to be maintained as per the statute in every mine having belowground workings .

Statement (1): The scale of the plan shall have representative factor of not less than 5000:1. Statement (2): It shall clearly show the areas which are naturally wet.

Statement (3): It shall clearly show the areas which require treatment with water indicating the system of water pipe lines laid down for the purpose.

A)     Statement (2) only

B)     Statement (1) & (2) only

C)     Statement (3) only

D)     Statement (1) & (3) only

E)     Statement (1) only

 

55)    As per the statute, which of the following is correct with regard to Danger of Inundation due to surface water ?

A)     No working shall be made beneath the surface water body but working can be done within 15 m of surface water body.

B)     Working can be made beneath and within 15 m of surface water body if the thickness of strata is more than 150 m.

C)     Development working can be made beneath and within 15 m of surface water body but for depillaring, permission shall be obtained from Chief Inspector of Mines.

D)     No working shall be made beneath and within 15 m of surface water body except with the previous permission of Chief inspector of mines

E)     No working shall be made beneath and within 15 m of surface water body.

 

56)    According to general rules that governs the erection of water barriers, at least how much water per sqaure metre roadway cross section, the water barrier must contain and atleast how long it should be ?

A)     175 litres and 17.5m

B)     250 litres and 25m

C)     200 litres and 20m

D)     100 litres and 10m

E)     150 litres and 15m

 

57)    The fan delivers 3600 m3/min of air at 700 Pa pressure. The input motor power is 168 kW. Find the the overall ventilation system efficiency in percent .

A)     72

B)     25

C)     66

D)     100

E)     12.5

 

58)    Find the coefficient of friction 'k' in Ns2/m4, if the air circulating is 3000 m3 / min through 2000 m long gallery of 2m X 5 m cross section and pressure developed is 70 Pa.

A)     0.0002

B)     0.0001

C)     0.001

D)     0.015

E)     0.1

 

59)    Air is supplied at a rate of 5 m3/s to 20 persons working at moderate rate (i.e. indivisual oxygen consumption rate of 0.03 litres/second) in a mine heading. The intake air contains 20.6percent oxygen. Determine the oxygen concentration in the exit air in percentage.

A)     20.232

B)     20.188

C)     20.588

D)     19.886

E)     20.248

 

60)    Vapour pressure 'e' at 99.99 kPa barometer and 301/300 K dry/wet-bulb temperature = 3.5 kPa. Find the density of air in kg/m3.

A)     1.17

B)     1.12

C)     1.19

D)     1.21

E)     1.14

 

61)    Match the following;

 

A)     A-4, B-2, C-1

B)     A-1, B-2, C-3

C)     A-4, B-1, C-2

D)     A-3, B-2, C-1

E)     A-4, B-2, C-3

 

62)    Find the combined resistance of four parallel airways having individual resistances 64, 4, 64 and 16 Ns2m8 respectively.

A)     148 Ns2m8

B)     1 Ns2m8

C)     128 Ns2m8

D)     4 Ns2m8

E)     2.9 Ns2m8

 

63)    The evaporator & condenser of a refrigeration unit have temperature of 5 and 50 degree centigrade respectively. Determine the maximum possible coefficient or Ideal coefficient of performance of this unit.

A)     6.58

B)     5.62

C)     5.78

D)     5.98

E)     6.18

 

64)    Match the following with respect to Graham's ratio

            Status of fire                                                                Graham's Ratio

         A. Active fire                                                                   1. 2.0

         B. Necessity for check up                                              2. 1.0

         C. Existence for fire                                                       3. 0.4

         D. Spontaneous heating appproaches active fire         4. 0.5

         E. Normal                                                                       5. 3.0

A)     A-1, B-4, C-5, D-2, E-3

B)     A-4, B-5, C-2, D-1, E-3

C)     A-5, B-4, C-2, D-1, E-3

D)     A-5, B-4, C-2, D-3, E-1

E)     A-1, B-4, C-2, D-5, E-3

 

65)    The power dissipitated in any given airway and hence, the cost of ventilating that airway depends upon --

A)     geometry of the airway

B)     the prevailing mean air density

C)     All the above

D)     the cube of the airflow

E)     roughness of airway

 

66)    According to recommondations of 12th National conference on safety in mines, the permisible respirable dust levels be brought down to -----------mg/m3 (In case percentage of free silica content up to 5) or           divided by percentage of free silica content in dust , from the present level, in line of prescribed limits of NIOSH, USA.

A)     2, 10

B)     1.5, 5

C)     3, 15

D)     1, 5

E)     2, 5

 

67)    Match the following;

            Shaft -features                                                Coefficient of friction, 'f' (dimensionless)

         A. Smooth lined, unobstructed                          1. 0.0067

         B. Brick lined, unobstructed                               2. 0.005

         C. Concrete lined, rope guides, pipe fittings     3. 0.0167

         D. Unlined, well trimmed                                    4. 0.0108

A)     A- 1, B- 2, C- 4, D- 3

B)     A- 3, B- 1, C- 4, D- 2

C)     A- 2, B- 4, C- 1, D- 3

D)     A- 2, B- 1, C- 4, D- 3

E)     A- 2, B- 1, C- 3, D- 4

 

68)    Find the length of mine airway; if air circulation is 9.5 m3/second with pressure requirement of 37.408 Pa, through a 2.1 m x 2.4 m roadway. The given coefficient of friction of the airway is 0.0098 N s2/m4.

A)     601.7m

B)     681.8m

C)     605.7m

D)     691.7m

E)     651.7m

 

69)    If air quantity circulated by the fan is 6000 m3 /min and pressure developed by the fan is 100 Pa, air power is equal to

A)     10 kW

B)     None of the above

C)     60 kW

D)     100 kW

E)     600 kW

 

70)    Identify the INCORRECT statement or statements with respect to Relative Humidity.

Statement (1): Relative humidity is the ratio of the current absolute humidity to the highest possible absolute humidity (which depends on the current air temperature).

Statement (2): If the Relative humidity is low, we can feel much cooler than the actual temperature as our sweat evaporates easily.

Statement (3): Relative humidity of mine air is generally measured using Kata Thermometer.

Statement (4): The same amount of water vapour results in higher relative humidity in cool air than in warm air.

A)     Statement (2) & (3) only

B)     Statement (2) & (4) only

C)     Statement (1) & (2) only

D)     Statement (3) only

E)     statement (1) & (4) only

 

71)    An Air Sample taken from old waterlogged workings showed the following composition. CO2-3.0percent, O2-16.2percent, N2- 79.5percent , CH4- 1.3 percent. (The composition of normal air by volume is O2- 20.93percent, N2-79.04percent & CO2- 0.03percent). Find the Blackdamp content of the sample.

A)     19.2

B)     17.18

C)     20.6

D)     21.31

E)     3.36

 

72)    The total pressure and the static pressure measured at a point in a ventilation duct are 20 mm and 10 mm of water gauge respectively. If density of air is 1.2 kg/m3, the velocity of the air in m/s is

A)     12.78

B)     6.24

C)     9.63

D)     8.53

E)     14.08

 

73)    Find the annual power cost ; if the air circulated by mine fan is 3000 m3/min with pressure drop of 0.5 kPa and combined Fan and motor efficiency is 80percent. Assume cost of power = Rs. 1/- per kW/h.

A)     Rs. 2,73,750/-

B)     Rs. 2,63,050/-

C)     Rs. 2,23,550/-

D)     Rs. 2,43,750/-

E)     Rs. 2,53,750/-

 

74)    Samples of air collected in the intake and return gates of an advancing longwall faceshow 0.3 and 0.8percent CH4 respectively.Calculate the methane emission per tonne of coal mined, if the production from the face averages 2000t per day and an air quantity of 40m3per second circulates along the face.

A)     12.57m3

B)     7.84m3

C)     8.64m3

D)     18.20m3

E)     9.46m3

 

75)    According to the statute, which of the following details shall be shown on the water danger plan of the mine :

(a)     every pumping & telephone station

(b)     every reservoir, dam or other structure either above or belowground;

(c)     the position of every dyke, fault & other geological disturbance

(d)     every haulage and travelling roadway

(e)     surface contour lines at specified intervals

A)     (a), (b) & (e) only

B)     (a), (b) & (d) only

C)     (b), (c) & (e) only

D)     (a), (b) & (c) only

E)     (a) & (d) only

 

76)    Illumination at a surface is directly proportional to        , where 'x' is the angle between the normal to the surface and the direction of the light rays.

A)     tan 'x'

B)     cot 'x'

C)     x2

D)     sin 'x'

E)     cos 'x'

 

77)    A fan is running at 750 rpm and passing air of inlet density of 1.2 kg/m3 with the shaft power of 440 kW. Assuming that the efficiency remains unchanged, calculate the corresponding new power, if the fan is run at 1500 rpm in air of density 1.1 kg/m3.

A)     2312.2 kW

B)     4000.0 kW

C)     3250 kW

D)     3226.6 kW

E)     32006. kW

 

78)    Psychometric chart shows the   of air along Y-axis against      along X-axis.

A)     dry bulb temperature, vapour pressure

B)     vapour pressure, dry bulb temperature

C)     vapour pressure, wet bulb temperature

D)     wet bulb temperature, vapour pressure

E)     wet bulb temperature, dry bulb temperature

 

79)    Dust suppression water is supplied to a workplace at a rate of 50 litres/tonne of coal mined. If the water is supplied to the machine at 12 degree centigrade and leaves the district at 26 degree centigrade; determine the cooling provided by the service water at a mining rate of 5 tonnes/minute.

A)     264.44 kW

B)     222.44 kW

C)     224.34 kW

D)     244.24 kW

E)     284.42 kW

 

80)    An underground coal mine district produces 520 tonnes of coal per day depoying 220, 200 and 192 persons in first, second and third shift respectively. Find the minimum quantity of air in m3/min to be provided in the ventilating district.

A)     1300

B)     1430

C)     1224

D)     1320

E)     1200

 

81)    Identify the CORRECT statement/statements regarding the Reynolds number:

Statement (1): The nature of flow of fluid (laminar or turbulent) is governed by a dimensionless parameter called the Reynolds number.

Statement (2): The Reynolds number determines the relative influence of viscosity on the flow pattern. Statement (3): Larger the Reynolds number , the larger is the influence of viscosity on the flow pattern.

A)     Statement (2) & (3) only

B)     Statement (1) & (3) only

C)     Statement (1) & (2) only

D)     Statement (2) only

E)     Statement (3) only

 

82)    Where A = mean 24 hourly output of coal from development face, t; q =methane emission of the seam being worked, m3/t; then the rate of methane emission Q in the development opening in m3/min could be expressed as -

A)     Q= qA/24x60

B)     Q= 4qA/24x60

C)     Q= 4q/A x 24 x 60

D)     Q= 2qA/24x60

E)     None of the above

 

83)    The Chemical used in self contained self rescuer to absorb exhaled CO2 is

A)     None of the above

B)     CaCO3

C)     KMnO3

D)     KO2

E)     LiOH

 

84)    In a mine having equivalent orifice of 2.4 m2, the water guage is 25mm. What will be new equivalent orifice if the water gauge is increased to 40 mm ?

A)     1.65 m2

B)     1.75 m2

C)     1.79 m2

D)     1.59 m2

E)     1.89 m2

 

85)    In a sealed off area, the air sample analysis report shows the following gas percentage O2-19.2, CO-0.8, CO2-2, and N2-78 , What will be the value of Graham's ratio, when fresh air contains 20.93percent O2, 79.04 N2 and 0.03 CO2 ?

A)     0.04

B)     None of the above

C)     0.54

D)     0.78

E)     1.36

 

86)    Identify the INCORRECT statement (s) with respect to Hydrogen gas.

Statement (1): When mixed with air it forms an explosive mixture. Statement (2): It is highly soluble in water.

Statement (3): It is heavier than air.

Statement (4): The gas may occur at battery charging stations.

A)     Statement (1) & (3) only

B)     Statement (2) & (3) only

C)     Statement (1) & (2) only

D)     Statement (3) only

E)     Statement (1), (2) & (4) only

 

87)    The specific gravity of water vapour is 0.622, when its molecular mass is 18 g/mol. Find the molecular mass of air.

A)     32.12 g/mol

B)     26.5 g/mol

C)     28.9 g/mol

D)     11.19 g/mol

E)     30.1 g/mol

 

88)    Identify the CORRECT statement or statements with respect to 'Anoxia'.

Statement (1): Anoxia happens when your body or brain completely losses it oxygen supply. Statement (2): When your body is harmed by a lack of oxygen, it is called a hypoxic-anoxia injury.

Statement (3): Anoxia means a total depletion in the level of oxygen. An extreme form of hypoxia or low oxygen.

A)     Statement (1) only

B)     Statement (1) & (2) only

C)     Statement (2) only

D)     All the statements

E)     Statement (2) & (3) only

 

89)    Match the following;

            Type of fire extinguisher         Band colour (for type identification)

         A. Water                                                 1. Green

         B. Dry chemical powder                         2. Red

         C. Halons                                               3. Blue

         D. CO2                                                   4. Black

A)     A- 2, B-1, C-3, D-4

B)     A- 2, B-3, C-1, D-4

C)     A- 2, B-3, C-4, D-1

D)     A- 4, B-3, C-1, D-2

E)     A- 3, B-2, C-1, D-4

 

90)    Calculate the Natural Ventilation Pressure in a mine with the following data:

(i)      Depth of Mine=300m,

(ii)     Pit bottom barometer reading=101.27Kpa,

(iii)    Pit top barometer reading=98.10Kpa,

(iv)    Average temp. in downcast shaft=305K and

(v)     Average temp. in upcast Shaft=307K

A)     22.81Pa

B)     22.80Pa

C)     25.78Pa

D)     30.81Pa

E)     21.8 Pa

 

91)    The law which provides that if a given mass of gas (V) is subjected to a change of pressure (P)and temperature (T)at one and same time, then, P1V1/T1 = P2V2/T2, is known as ----

A)     Le Chatelier's equation

B)     Bernoulli's Theorem

C)     None of these

D)     Graham's Law

E)     Kirchoff's Law

 

92)    Ventilation district means such part of a mine below ground that has an --

A)     independent intake airway commencing from a main intake airway and an independent return airway terminating at a main return airway

B)     independent intake airway commencing from a main intake airway or an independent return airway terminating at a main return airway

C)     independent return airway terminating at a main return airway

D)     independent intake airway commencing from a main intake airway and an auxilliary ventilation system

E)     None of the above

 

93)    What is the pressure required to circulate 30 m3/s of air through a 600 m long rectangular mine airway of cross-section 2 m high and 3 m wide, if the co-efficient of friction of the airway is 0.01 Ns2/m4 ?

A)     375 Pascal

B)     620 Pascal

C)     250 Pascal

D)     400 Pascal

E)     130 Pascal

 

94)    Identify the CORRECT statement/statements with regard to proneness to heat stroke: Statement (1): People having constipation and alcoholics are more prone to heat stroke.

Statement (2): The persons with low body weight and having low work capacity fall an easier pray to heat stroke. Statement (3): Older men (over 45 years ) are less liable to heat stroke than younger men.

Statement (4): Gross overweight persons with low work capacity are also prone to heat stroke.

A)     Statement (1), (2) & (4) only

B)     Statement (2) (3) & (4) only

C)     Statement (3) & (4) only

D)     Statement (1) & (3) only

E)     Statement (2) & (3) only

 

95)    A fan ventilating a heading through a duct of 600mm diameter circulates 4m3s-1 of air at the face . Calculate the heat added to the air by the fan, if the input power of the fan is equal to 2.9kW. Density of air is to be assumed equal to 1.2kgm-3 .

A)     2421 J

B)     2562 J

C)     2329 J

D)     2022 J

E)     2127 J



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