SMU-MINE VENTILATION DGMS EXAM-2021

20-04-2021
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Question Paper _ Key of DGMS SECOND CLASS UNRESTRICTED UNDER MMR - MINE VENTILATION

No. of Questions: 100

Duration in Minutes: 120

1) Mean air temprature of 450 m deep downcast shaft is 29 degC and that of upcast shaft is 37 degC. The height of motive coloumn in m is -

A) 12.8

B) 9.5

C) 8.2

D) 10.2

E) 11.6

2) Air sample taken from a return airway yeilds the following analysis: N2 = 79.22 percent, O2 = 20.5 percent, CO = 18 ppm. Find the Graham's ratio. (Assume air is supplied with 20.93 percent O2 and 79.04 percent N2).

A) 0.19

B) 0.12

C) 0.32

D) 0.24

E) 0.88

3) Identify the WRONG statement/statements with respect to precautions to be taken in safety lamp rooms.

Statement (I): Only such quantity of volatile spirit as is required for two working days shall be kept in safety lamp room.

Statement (II): No unathorised person shall enter the safety lamp room.

Statement (III): No person shall smoke in safety lamp room.

A) Statement (II) only

B) Statement (I) only

C) Statement (I) & (III) only

D) Statement (III) only

E) Statement (I) & (II) only

4) Match the following;

Instrument for air velocity measurement Conditions for use

1. Vane anemometer A. For low velocity. Easy to use, but not very accurate.

2. Hot wire Anemometer B. For low to high velocity. Highly accurate, easy to use but expensive and requires care.

3. Smoke tube C. For medium to high velocity. Commonly used . Good accuracy when used carefully.

D. For High velocity only. Extremely accurate but difficult to use, very cheap & requires little care in use.

A) 1- C, 2-B, 3- A

B) 1- A, 2-B, 3- C

C) 1- C, 2-B, 3- D

D) 1- C, 2-D, 3- A

E) 1- D, 2-B, 3- A

5) Match the following;

The Gas Laws States that

A. Boyle's Law 1. The relative rates of diffusion of number of gases vary inversely as the square root of their relative densities

B. Charle's Law 2. The volume of a given mass of gas is directly proportional to its absolute temperature when pressure is constant

C. Graham's Law 3. The volume of given mass of gas varies inversely as the absolute pressure, if temperature remains constant

A) A-3, B-2, C-1

B) A-2, B-1, C-3

C) A-1, B-2, C-3

D) A-1, B-3, C-2

E) A-2, B-3, C-1

6) What is the pressure required to circulate 20 m3/s of air through a mine airway of 200 m long, 3 m high & 3 m wide ? (The co-efficient of friction of the airway is 0.01 Ns2/m4).

A) 17.13

B) 23.17

C) 11.37

D) 19.17

E) 13.17 pa

7) A forcing fan handles --------- atmospheric air and has a life compared to the exhaust fan.

A) denser, limited

B) pure, fixed

C) clean, longer

D) clear, shorter

E) hot, shorter

8) A "-----------" barometer indicates increasing air pressure; a " " barometer indicates decreasing air pressure.

A) None of the above

B) steday, rising

C) rising, falling

D) falling, steady

E) falling, rising

9) As per Atkinson Formula, the quantity varies inversely as the square root of ------

A) None of the above

B) pressure

C) coefficient of friction

D) fan speed

E) area

10) The point at which mine characteristic curve and fan characteristic curve intersect is called -.

A) Operating point

B) Neutral point and stall point

C) None of these

D) Stall point

E) Neutral point

11) The product of average air -------- at any point in a mine airway and the of the airway at that point gives as estimation of the air quantity.

A) velocity, cross sectional area

B) density, cross sectional area

C) speed, width

D) speed, height

E) pressure, resistance

12) In case of skip winding there is a formation of more during the loading of the skip and it is a general practice to install the skips in shafts.

A) compression, material handling

B) dust, upcast

C) dust, downcast

D) heat, ventilation shaft

E) None of the above

13) The long term exposure to radioactive substances can cause -------------and --.

A) poisioning, mental disorder

B) mental disability, poisioning

C) fatigue, behavioral disorder

D) cancer, genetic disorders

E) tubeculosis, physical disorder

14) Which of the following instruments is used to measure the cooling power of the air?

A) Manometer

B) Thermometer

C) Velometer

D) Anemometer

E) None of these

15) Identify the CORRECT statement or statements with respect to Hydrogen Sulphide.

Statement (1): One of the sources of Hydrogen Sulphide in mines is blasting in heavy sulphide ores.

Statement (2): A filter paper soaked in lead acetate solution exposed to an atmosphere containing H2S, turns brown and subsequently black within one to two minutes.

Statement (3): In metal mines action of acid water on iron pyrites, gypsum produces Hydrogen sulphide.

A) Statement (2)& (3) only

B) Statement (1) only

C) All the statements

D) Statement (2) only

E) Statement (1) & (2) only

16) If the RPM of Mechanical Ventilator is increased by 10percent, then power demand of the fan would -

A) None of these

B) Increase by 10percent

C) Decrease by 10percent

D) Decrease by 33percent

E) Increase by 33percent

17) What amongst the following precaution(s) shall be taken during the whole time when any work of dealing with or sealing off a fire or heating belowground is in progress –

Precaution (A): A competent person shall be present on the spot throughout.

Precaution (B): Means of detecting methane gas approved by the Chief Inspector shall be kept at all places where persons are employed.

Precaution (C): There shall be available, at or near the place, two smoke helmets or other suitable apparatus for use in emergency.

A) Precaution (B) & (C)only

B) Precaution (A) & (B) only

C) All the precautions

D) Precaution (A) & (C) only

E) Precaution (A ) only

18) A fan running at 850 r.p.m., is passing an air flow of 150 m3/s. Assuming the efficiency remains unchanged, find the new quantity of airflow, if the fan runs at 1100 r.p.m.

A) 194.1 m3/s

B) 184.1 m3/s

C) 792.2 m3/s

D) 167.8 m3/s

E) 231.3 m3/s

19) A fan running at 850 r.p.m., is passing air of inlet density 1.2 kg/m3 with shaft power of 440 kW. Assuming the efficiency remains unchanged, find the new shaft power, if the fan runs at 1100 r.p.m. in air density of 1.1 kg/m3.

A) 774 kW

B) 974 Kw

C) 674 Kw

D) 874 kW

E) 574 Kw

20) Match the following;

Type of dust/fibre Maximum Allowable concentration of airborne respirable dust (as per MMR, 1961)-8 hours TWA

1. Manganese ore A. Two fibres per mililitre of air sampled

2. Asbestos B. Five milligrams per cubic metre of air sampled

3. Other ores C. The value of fifteen divided by percentage of free respirable silica present

D. One fibre per mililetre of air sampled.

A) 1- D, 2- A, 3-C

B) 1- B, 2- A, 3-D

C) 1- B, 2- A, 3-C

D) 1- B, 2- D, 3-C

E) 1- A, 2- B, 3-C

21) To obtain correct measurement of wet bulb temperature the whirling hygrometer should be rotated at least for ---------.

A) 1 min

B) 4 min

C) 5 min

D) 2 min

E) 3 min

22) Which of the following statement or statements with respect to Frictional losses is/are INCORRECT

Statement (A): Frictional pressure losses are caused by the resistance of the walls on the airstream.

Statement (B): Frictional losses are the result of changes in air direction.

Statement (C): Frictional losses depends upon conditions and roughness of individual wall surfaces and velocity of air.

A) Statement (A) & (C) only

B) Statement (B) only

C) Statement (A) only

D) Statement (C) only

E) Statement (A) & (B) only

23) Minimum requirement to ventilate a 50 m long rodway or tunnel in underground metal mine by an auxiliary fan will be --

A) Auxilliary fan capable of providing 150 cubic meter of air per minute within 4.5 m of the face

B) Auxilliary fan capable of providing 250 cubic meter of air per minute within 5 m of the face

C) Auxilliary fan capable of providing 200 cubic meter of air per minute within 4.5 m of the face

D) None of the above

E) Auxilliary fan capable of providing atleast 300 cubic meter air per minute within 4.5 m of the face.

24) Match the following;

Gas Known as

A. CH4 1. Inert gas

B. SO2 2. Non toxic but explosive gas

C. N2 3.Acutely poisonous gas

4. Gas which supports combustion

A) A-3, B-2, C-1

B) A-1, B-2, C-3

C) A-4,B-2, C-1

D) A-2, B-4, C-1

E) A-2, B-3, C-1

25) What do you mean by gauge pressure ?

A) None of these

B) Absolute pressure

C) difference between absolute pressure and atmospheric pressure

D) Static pressure plus velocity pressure

E) barometirc presssure

26) According to statute; dead leaves or dry vegetation shall not be allowed to accumulate or remain, and combustible materials other than material required for use within a period of , and inflammable materials, shall not be stored within a distance

A) 72 hours, 14

B) 12 hours, 10

C) 7 days, 30

D) 24 hours, 15

E) 2 days, 21

27) Mean air temprature in a downcast shaft of 400m depth is 28degC and in the upcast shaft is 38degC, calculate the NVP assuming average barometric pressure in dowcast shaft to be 750mm of Hg.

A) 148.1 Pa

B) 240 Pa

C) 100.2 Pa

D) 200.2 Pa

E) 244.5 Pa

28) Calculate the extent of rubbing surface in a circular shaft of 6m diameter, and 1200 m deep.

A) 24567.8 sq.m

B) 20628.6 sq.m

C) 22628.5 sq.m.

D) 24567.8 m

E) 20456 cu.m

29) Men through the process of 'A' produce heat. 'A' is given by

A) Dehyderation

B) None of these

C) Acclimatisation

D) Salt depletion

E) Metabolism

30) Mean temperature in D.C. shaft, 500m deep, is 27 degree centigrade and in U.C. shaft it is 37 degree centigrade. Calulate the motive column.

A) 14.13 m

B) 17.47 m

C) 16.13 m

D) 18.78 m

E) 17.67 m

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

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) Permission is to be obtained form Regional inspector of mines

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

32) Match the following.

Fan Type (Centrifugal) Fan Diameter for a given head capacity

A. Forwarward bladed 1.Largest

B. Radial bladed 2. Least

C. Backward bladed 3. Intermediate

A) A-1, B-2, C-3

B) A-2, B-1, C-3

C) A- 2, B-3, C-1

D) A-3, B-2, C-1

E) A-3, B-1, C-2

33) Silicosis is charactrised by the development of fibrosis in the lung tissue.

A) ocular

B) rectangular

C) None of the above

D) nodular

E) circular

34) No person shall be re-admitted into the place where the gas was detected untill a competent person has -

A) examined the place & removed the gas by operating the auxiliary fan.

B) examined the place and has reported that the place is free from gas

C) examined the place and improved the air velocity at the place to remove the gas

D) examined the place and ensured that every person is carrying a self rescuer

E) examined the place and & ventilation is improved to dilute the gas

35) Identify the CORRECT statement or statements with respect to "Motive coloumn" & "NVP".

Statement (1): In case of N.V.P. it is the excess wight of air in downcast air coloumn which give rise to the N.V.P.

Staement (2): The height of the excess weight of air coloumn of downcast shaft, 1 sq. Metre in cross section which give rise to N V P is called motive coloumn.

Statement (3): The motive coloumn when reffered to N V P is the preponderant or unbalanced part of the whole downcast coloumn, 1 sq. m. in cross secion.

A) Statement (1) only

B) All the statements

C) Statement (2) & (3) only

D) Statement (1)& (3) only

E) Statement (2) only

36) Imparting initial training in rescue and recovery work is a function of --.

A) None of the above

B) Rescue room

C) Rescue Room with additional equipments

D) Rescue brigade

E) Rescue station

37) Identify the CORRECT statement/statements with respect to shock pressure losses.

Statement (A): It is caused by abrupt changes in velocity of air movement.

Statement (B): Shock losses are the result of changes in air direction or of airway area, obstructions and regulation.

Statement (C): It is caused by the resistance of the walls on the airstream.

A) Statement (A) & (B) only

B) All the statements

C) Statement (B) only

D) Statement (A) only

E) Statement (C) only

38) Large ventilation fan with high starting torque, the preferable motor will be

A) None of the these

B) Squirrel cage Induction Motor

C) Slip ring Induction Motor

D) Capacitor start Motor

E) DC shunt Motor

39) While designing ventilation system for a mine which are the following factors should be considered for accounting pressure loss in a projected mine airway-

A) Shock loss

B) Friction loss

C) Probable obstructions in roadways

D) Leakage between upcast & downcast shafts

E) All of the these

40) Match the following;

Ventilation devices Purpose

A. Door 1. To reduce the airflow to a desired level.

B. Stoppings 2. To chanel air flow for effective air distribution

C. Air crossing 3. Air bridge where intake and return airways are required to cross each other

A) A- 4, B- 2, C-1, D-3

B) A- 4, B- 2, C-3, D-1

C) A- 2, B- 4, C-3, D-1

D) A- 4, B- 3, C-2, D-1

E) A-1, B- 2, C-3, D-4

41) The factor(s) governing the design of dam in belowground mine include -

A) Nature of the adjacent strata, form of dam, materilas used in construction & size of roadway

B) Form of dam, materials used in construction, size of roadway, estimated water pressure

C) Nature of the adjacent strata, form of dam, materials used in construction, size of roadway, estimated water pressure

D) Nature of the adjacent strata, height of roadway, form of dam & materilas used in construction

E) Size of roadway, roughnes of surface, form of dam & estimated water pressure

42) Three major sources of generation of nitrous fumes in a underground mine are

A) Use of explosive, Diesel Exhaust, Welding

B) Use of cement, wooden support , steel structures

C) Water logging, use of wooden supports, auxiliary ventilation

D) Explosive, wooden support, watery strata

E) None of the above

43) Purpose of the ventilation in mine is------

A) To supply necessary oxygen to dilute noxious gases

B) To clear out smokes & blasting fumes

C) Option (A), (B) & (C)

D) To minimize the temperature & humidity in mine

E) Option (B) and (C)

44) State the type or types of Auxiliary ventilation system that can be adopted in a mine.

A) Forcing

B) Exhausting

C) All of these

D) Overlapping

E) Reversible

45) The resistance in a ventilation duct can be reduced by

A) Using duct with large diameter

B) Using duct of very long length

C) None of these

D) Increasing the flow of the air though the duct

E) Using duct having corrugated internal surface

46) The relation between pressure(P), resistance(R) & quantity(Q) is expressed by the formula ---

A) None of these

B) P=R2Q

C) P=R/Q

D) P=RQ3

E) P=RQ

47) Barometric pressure or Atmospheric pressure is defined as

A) colum height of mercury / dia of the barometer tube

B) force per unit area exerted against a surface by the weight of air above that surface

C) Atomic weight of mercury / atomic weight of air

D) None of these

E) weight of mercury in barometer per unit area

48) Match the following;

Lighting related 'Terms' Meaning

A. Illuminance 1. Is a subjective evaluation of luminance.

B. Luminance 2. Is the level of light emmited from the surface of light source or surface to be viewed and expressed in the unit of cd/m2.

C. Brightness 3. Is the level of light falling on the surface to be viewed and is expressed in the unit of lux (lm/m2).

4. Is ratio of reflected light and incident light.

A) A- 4, B-1, C-3

B) A- 3, B-4, C-1

C) A- 3, B-2, C-1

D) A- 4, B-2, C-1

E) A- 3, B-2, C-4

49) Non- collagenous Pneumoconiosis is caused by --.

A) fibrogenous dust

B) asbestos fibres

C) Non-fibrogenous dust

D) None of these

E) asbestos dust

50) In soda acid type fire extinguisher, the --------------- is liberated by the action of acid on --.

A) N2, calcium corbonate

B) foam, sodium bi-carbonate

C) 02, sodium chloride

D) CO, lime powder

E) CO2, baking soda

51) In case of Kata Thermometer, the kata factor of an instrument is the number of millicalories of heat which it loses per square cm of surface area of the bulb on cooling from ------- degrees centigrade to degrees centigrade.

A) 33.5, 30

B) 38 , 35

C) 30, 33.5

D) 38, 33.5

E) 35, 38

52) Identify the WRONG statement or statements with respect to "Heat Stroke" .

Statement (1): Heat stroke results from the breakdown of the temperature regulating mechanism of the body.

Staement (2): Vomiting is not a usual symptom of heat stoke.

Statement (3): In early stages of heat stroke, it is characterised by mental excitement, followed by restlessness, intolerance & delirium.

A) All the statements

B) Statement (1) only

C) Statement (1)& (2) only

D) Statement (1) & (3) only

E) Statement (2) only

53) The cooling power should equal or exceed the metabolic heat rate for any work rate in order to dissipate all heat produced by the human body.

A) evaporative

B) None of the above

C) combined

D) specific

E) absolute

54) Velocity of air at face between ------ m/s to m/s is reasonable for comfortable working condition & velocities above this generally cause discomfort and raise dust.

A) 0.5, 2.0

B) 0.5, 1.0

C) 0.5 , 1.5

D) 1.0, 3

E) 1.0 , 2.5

55) The simplest method of detecting carbon monoxide in mines is --.

A) using detector

B) None of the above

C) using flame safety lamp

D) exposing a bird in a cage to the atmosphere containing gas

E) by chemical analysis

56) The reading of anemometer before and after meauring the velocity were 1500 & 3000, respectively when the instrument was held in air current for three minutes. Find the quantity of air flowing in m3/min , if the roadway is 5m wide & 3 m high.

A) 6575

B) 7500

C) 8525

D) 7250

E) 8750

57) Match the following - Comparison of the different types of Centrifugal fans.

Type of fan No. of blades

A. Forward bladed 1. 24-64

B. Radial bladed 2. 8-16

C. Backward bladed 3. 4-24

A) A-2, B- 1, C- 3

B) A-1, B- 3, C- 2

C) A-1, B- 2, C-3

D) A-2, B- 3, C-1

E) A-3, B- 1, C- 2

58) Match the following;

Efficiencies Expressed as

A. Manometric efficiency 1. Ratio of the power in the air to the input power.

B. Hydraulic efficiency 2. Ratio of the available total head to the input head.

C. Total efficiency 3. Ratio of actual total head to the theoretical or Euler's head

4. Ratio of input head to Euler's head

A) A- 3, B- 2, C-1

B) A- 4, B- 2, C-1

C) A- 3, B- 2, C-4

D) A- 3, B- 4, C-1

E) A- 1, B- 2, C-4

59) If the percentage of free respirable silica content of the dust is 7.5 percent, then what will be the 'permissible limit' of 8 hrs-TWA concentration of airborne respirable dust in case of ores other than manganese ore, as per the prevailing statute ?

A) 5 mg/m3

B) 3 mg/m3

C) 1 mg/m3

D) 4 mg/m3

E) 2 mg/m3

60) The stink damp is ------

A) Synonymous with CH4

B) Mechanical mixture of extinctive gases CO2& excess N2

C) None of these

D) Synonymous with SO2

E) Synonymous with CO

61) Match the following;

Mineral Sulpher percent

A. Pyrite, FeS2 1. 13.4

B. Chalcopyrite, CuFeS2 2. 53.3

C. Galena, PbS 3. 74.4

4. 34.9

A) A-3, B-4, C-1

B) A-1, B-4, C-3

C) A-2, B-4, C-1

D) A-2, B-3, C-1

E) A-2, B-4, C-3

62) The instrument used in general for air quantity survey in belowground mine is --.

A) Megar Meter

B) Hygrometer

C) None of the above

D) Manometer

E) Thermometer

63) An equivalent orifice of a mine is the ----- of an imaginary opening in a thin plate which offers the same to the passage of air as is offered by the mine itself.

A) length, friction

B) circumference, resistance

C) area, resistance

D) perimeter, resistance

E) area, pressure

64) The production of dust shall be reduced by keeping suitable pressure on the and by keeping the holes clear of the .

A) bits, cuttings

B) ground, mud

C) drill rod, dust

D) None of the above

E) driller, water

65) When the pressure is increased by 50percent , What is the effect on velocity ?

A) The velocity is increased 1.22 times

B) The velocity increased 2 times

C) The velocity is decreased 50 percent

D) The velocity remains constant

E) The velocity is decreased 1.22 times

66) A ventilator running at 160 r.p.m. and producing 25 mm of w.g., is speeded up 25 percent. Find the new water gauge developed.

A) 36 mm

B) 31.25 mm

C) 45mm

D) 42 mm

E) 39 mm

67) What pressure is required to produce 1200 cubic metre of air per minute in a mine whoes equivalent orifice is 1 sq.metre ? (Assume standard air density).

A) 665.64 Pa

B) 777.99 Pa

C) 800 Pa

D) 690.84 Pa

E) 742.88 Pa

68) Find the area of rubbing surface in a mine roadway of 4.5m wide, 3 m high, and 1000 m long.

A) 13,500 sq. m

B) 13500 m

C) 15,000 m

D) 15,000 sq.m

E) 10,000 sq.m

69) The speed of a fan developing 50 HP is increased from 100 r.p.m. to 200 r.p.m. What is the HP required to maintain the increased speed ?

A) 300 HP

B) 500 HP

C) 400 HP

D) 100 HP

E) 200 HP

70) Identify the CORRECT statement or statements with respect to Main Mechanical Ventilator (MMV).

Statement (1): At every MMV, a suitable pressure recording gauge or water gauge shall be provided.

Statement (2): At every MMV, there shall be provided a properly constructed air lock, if the shaft/winze is ordinarily used for lowering or raising of persons or material , where mechanical ventilator is installed.

statement (3): At every MMV, there shall be provided a continous monitor indicating percentage of different mine gases.

A) Statement (1) & (2) only

B) Statement (2) only

C) Statement (2) & (3) only

D) Statement (3) only

E) sttement (1) only

71) Match the following;

Mine Gases Characteristic

A. Nitrogen 1. Asphyxiant

B. Methane 2. Poisonous gas

C. Carbon monoxide 3. Explosive gas

D. Carbon dioxide 4. Inert gas

A) A-1, B-3, C-2, D-4

B) A-4, B-3, C-2, D-1

C) A-4, B-3, C-1, D-2

D) A-4, B-2, C-3, D-1

E) A-3, B-4, C-2, D-1

72) Match the following;

Mine Gases Explosibility limit

A. H2S 1. 12.5 to 75 percent

B. H2 2. 4.3 to 45.5 percent

C. CO 3. 5.4 to 14.8 percent

4. 4.1 to 74 percent

A) A- 2, B-4, C-1

B) A- 3, B-4, C-1

C) A-4, B-3, C-1

D) A- 2, B-4, C-3

E) A-1, B-4, C-2

73) Identify the WRONG statement or statements with respect to 'sulphide dust'.

Statement (1): Minimum oxygen concentration to support a dust explosion is 18percent.

Statement (2): Sulphide ores have about 20percent as much energy (fuel) as coal and if an explosion occurs it is somewhat less violent

Statement (3): Oxidation of sulphur bearing mineral can be extremely rapid.

A) All the statements

B) Statement (2) & (3) only

C) Statement (1)& (3) only

D) Statement (1) only

E) Statement (2) only

74) A water gauge of 20 mm is capable of passing 6,000 m3/min of air through a certain mine. What must be the water gauge in mm, if quantity is increased to 10,000 m3/min without any change in the conditions ?

A) 45.67

B) 66.66

C) 40. 55

D) 50.67

E) 55.55

75) If the length of an airway is increased from 1000 m to 1800 m, how much must the w.g. be increased ( or decreased) to maintain the same velocity ? Take the origional w.g. to be 50mm.

A) 100 mm

B) 90 mm

C) 75 mm

D) 85 mm

E) 80 mm

76) If the percentage of free respirable silica content of the dust is 10 percent, then what will be the 'permissible limit' of 8 hrs- TWA concentration of airborne respirable dust in case of ores other than manganese ore, as per the prevailing statute ?

A) 1.5 mg/m3

B) 2.5 mg/m3

C) 2 mg/m3

D) 1 mg/m3

E) 3 mg/m3

77) The mine has two splits. Pressure across the splits is 100mm. Air flow in one split is 15m3/sec. and in other spilt is 30m3/sec. Calculate the size of the regulator to equalise the air quantity.

A) 0.761m2

B) 0.961m2

C) 0.671m2

D) 0.69m2

E) None of the above

78) What pressure is required to produce 6,00 cubic metre of air per minute in a mine whoes equivalent orifice is 1 sq.metre ? (Assume standard air density).

A) 185.5 Pa

B) 160.4 Pa

C) 166.41 Pa

D) 175.6 Pa

E) 148.5 Pa

79) Identify the CORRECT statement or statements with respect to Relative Humidity.

Statement (1): Relative humidity is the ratio of the partial pressure of water vapour to the equilibrium vapour pressure of water at agiven temperature.

Statement (2): The same amount of water vapour results in higher relative humidity in cool air than in warm air.

Statement (3): Relative humidity depends on temperature and pressure of the system of interest.

A) Statement (3) only

B) sttement (1) only

C) All the statements

D) Statement (2) only

E) Statement (1) & (2) only

80) Where it is intended to carry out exploratory work in a mine or part thereof likely to contain irrespirable atmosphere certain precautions are required to be taken. Which amongst the following precaution or precautions is/are INCORRECTLY stated ?

Precaution (1): No party of less than Six persons shall be allowed to proceed to carry out such work.

Precaution (2): No party of less than five persons shall be allowed to proceed to carry out such work.

Precaution (3): Every such party shall carry a cage containing suitable birds or other means of detecting carbon monoxide gas approved by the Chief Inspector and also an approved flame safety lamp.

A) Precaution (1) only

B) Precaution (3) only

C) Precaution (1) & (2) only

D) Precaution (1) & (3) only

E) Precaution (2) only

81) Illumination at a surface is inversely proportional to the of the distance of the surface from the source of light.

A) half

B) cube root

C) square root

D) square

E) cube

82) Identify the WRONG statement/ statements with respect to "splitting" of airways ?

Statement (A): Splits reduce the overall resistance of the mine.

Statement (B): Splitting does not help in providing fresh uncontaminated air to each district.

Statement (C): Splitting helps in keeping up the air velocities in roadways by increasing the air quantity.

A) Statement (A) only

B) Statement (B) & (C) only

C) Statement (C) only

D) Statement (B) only

E) Statement (A) & (B) only

83) Identify the CORRECT statement or statements with respect to "Artificial aids to natural ventilation" .

Statement (1): Stacks built on the top of the downcast shafts aid natural ventilation.

Staement (2): N. V. P. can be considerablly increased by putting furnaces at the bottom of upcast shaft.

Statement (3): Surafce winds, if suitably directed into the mine, aid natural ventilation by adding velocity pressure to the N.V.P.

A) Statement (1) only

B) Statement (1)& (2) only

C) Statement (2) & (3) only

D) Statement (2) only

E) All the statements

84) Choose the correct statement:

A) Rate of diffusion of gases into air is directly proportional to their densities.

B) Rate of diffusion of gases into air is inversely proportional to the square root of their densities

C) Rate of diffusion of gases into air is directly proportional to the square root of their densities

D) Rate of diffusion of gases into air is inversely proportional to their densities.

E) None of these

85) Fan is circulating 20000 m3/min air with pressure development of 700 pascals. The air power is --

A) 312 HP

B) 511 HP

C) 411 HP

D) 711 HP

E) 611 HP

86) Identify the CORRECT statement or statements with respect to "Effect of Air Velocity" .

Statement (1): Higher air velocity aids evaporative cooling.

Staement (2): Increase in air velocity up to 1 m/s markedly improves the comfort condition.

Statement (3): Air velocity more than 1m/s and up to 4 m/s provides the best cooling effect and therby remarkably improve the comfort condition.

A) Statement (1)& (2) only

B) Statement (2) & (3) only

C) Statement (1) only

D) Statement (2) only

E) All the statements

87) No person goes into or work or is allowed to go into or work at any place where the respirable dust concentration is in excess of the 'permissible limit' unless he wears a suitable --.

A) oxygen mask

B) dust respirator

C) face mask

D) breathing apparatus

E) None of these

89) The amount of water carried by ventilating air is 7 g/m3. If the quantity of air circulating in a mine is 6000 m3/min; Calculate the amount of water carried by the ventilating air per day.

A) 64.28 Tonnes

B) 78.90 tonnes

C) 65.78 Tonnres

D) 60.48 Tonnes

E) 66.77 Tonnes

90) Identify the CORRECT statement or statements with respect to 'sulphide dust'.

Statement (1): Iron containing disulphides such as chalcopyrite and pyrite are the most reactive and have the lowest ignition temperatures, shortest thermal exposures for initiation and highest burning intensities.

Statement (2): Iron containing disulphides such as Chalcopyrite and Pyrite dusts are the most susceptible to 'flash' initiation and explosive propagation.

Statement (3) The metal monosulphides are less reactive, in the presence of moisture they may 'age' or weather to produce elemental sulphur in forms that dramatically lower dust ignition energies.

A) Statement (1) & (2) only

B) Statement (2) only

C) Statement (1) only

D) All the statements

E) Statement (1)& (3) only

91) 45 HP fan maintains air velocity of 60 m/min in a mine. What will be the velocity, if the power is doubled ?

A) 75.5 m/min

B) 100 m/min

C) 90 m/min

D) 135 m/min

E) 180 m/min

92) If the density of Hydrogen is 1 (one) and that of Methane is 8 (eight), then the Hydrogen diffuses times as quickly as Methane.

A) 2.83

B) 8

C) 2.36

D) 4

E) 3.6

93) Match the following;

Type of dust Disease

P. Silica 1. Asbestosis, cancer lung

Q. Asbestos 2. Anthracosis

R. Iron 3. Siderosis

4. Silicosis

A) P-1, Q-3, R-2

B) P-4, Q-1, R-2

C) P-3, Q-1, R-4

D) P-2, Q-1, R-4

E) P-4, Q-1, R-3

94) Match the following;

O2 percent Physiological effect

A. 17 percent 1. Unconsciousness within one minute.

B. 15percent 2. Breathing faster & deeper

C. 13 percent 3. dizziness, buzzing in the ears and rapid heart beat.

4. Unconsciousness after prolonged exposure

A) A-2, B-3, C-4

B) A-2, B-3, C-1

C) A-1, B-3, C-4

D) A-3, B-4, C-1

E) A-1, B-2, C-3

95) Identify the CORRECT statement or statements with respect to "Lighting" in mines .

Statement (1): Lighting in mines presents special problems due to dark souroundings and low reflectance of mine surfaces.

Staement (2): The reflectance depends on the nature of ore/overburden.

Statement (3): Due to continuous sprinkling of water for dust suppresion, the surface reflectivity further increases, resulting in good visibility.

A) Statement (2) only

B) All the statements

C) Statement (2) & (3) only

D) Statement (1)& (2) only

E) Statement (1) only

96) Identify the CORRECT statement or statements with respect to Nitrogen gas.

Statement (1): Nitrogen is produced due to decomposition of organic substances . Statement (2): Nitrogen is produced due to blasting with explosives in mines.

Statement (3): Nitrogen supports life and combustion.

A) Statement (1) only

B) All the statements

C) Statement (1) & (2) only

D) Statement (2)& (3) only

E) Statement (2) only

97) A fan making 250 r.p.m. circulates 10,000 m3/min of air through a mine. If the speed be incresed to 300 r.p.m., what quantity will then pass in the mine ?

A) 13000 m3/min

B) 11500 m3/min

C) 13500 m3/min

D) 12000 m3/min

E) 15000 m3/min

98) Match the following;

Terms Formula

A. Force 1. 1/2 mass x velocity2 (J)

B. Kinetic energy 2. Force x distance (J)

C. Potential energy 3. mass x gravity (N)

4. 2 mass x velocity2 (J)

A) A- 1, B-2, C-3

B) A- 2, B-1, C-3

C) A- 4, B-1, C-3

D) A- 4, B-1, C-2

E) A- 3, B-1, C-2

99) A fan is driven by a DC motor having the motor efficiency 85 percent, the voltage being 550 & current being 120 amperes. Calculate the mechanical efficiency of the fan, if H.P. in air = 47.3 HP.

A) 68.90percent

B) 62.90percent

C) 58.79percent

D) 56.67percent

E) 60.80percent

100) Air sample produces the following results. CH4 = 8 percent, CO = 5 percent, H2 = 3 percent. Detrmine Upper Explosibility Limit (UEL) of this mixture. (Assume UEL of CH4 : 14 percent, CO : 74.2 percent & H2 : 74.2 percent ).

A) 54.13

B) 20.18

C) 23.56

D) 34.48

E) 44.44