Mine Environment — Part 1 MCQs with Explanations

Anemometer should be moved throughout the cross section of the roadway is the correct answer to “How the anemometer is used to determine the average velocity of air”. This question is standard in competitive examination syllabi for Mine Environment.

SO2 and NOx is the correct answer to “The important gaseous pollutants, contributing to acid rains, are”. This question is standard in competitive examination syllabi for Mine Environment.

lag on ignition is the correct answer to “The delay between the ignition and the application of the heat source termed as”. This question is standard in competitive examination syllabi for Mine Environment.

521 is the correct answer to “A high volume air sampler is operated for 8 hrs in a mine with the flow rate of air varying from 1.5 m 3 /min to 1.3 m 3 /min. The empty weight of the filter paper is 2.30 g and the final weight is 2.65 g. The mean concentration of the suspended particulate matter (SPM) during the study period in μg/m 3 is”. This question is standard in competitive examination syllabi for Mine Environment.

2000 Hz is the correct answer to “What is the center frequency of the band number whose lower and upper bands are 1414 and 2828 Hz respectively”. This question is standard in competitive examination syllabi for Mine Environment.

to withdraw workers from the mine as early as possible is the correct answer to “The primary aim of ventilation control in the event of fires is”. This question is standard in competitive examination syllabi for Mine Environment.

angle between guide vane inlet and the direction of the absolute velocity of air leaving the impeller is small or equal to is the correct answer to “The curvature of diffuser vane shall be so fixed that the fluid enters the guide passage with minimum loss. This is possible only when”. This question is standard in competitive examination syllabi for Mine Environment.

0.716 Kg is the correct answer to “What is the mass of 1 m 3 CH 4 at NTP”. This question is standard in competitive examination syllabi for Mine Environment.

1687.5 m3/min is the correct answer to “What should be minimum quantity of air to be circulated along a long wall face at its maximum speed of 7.5m for a 3m thick gassy seam of 3 rd degree”. This question is standard in competitive examination syllabi for Mine Environment.

10 micron is the correct answer to “Hairs of our nose can remove all particles of size, greater than”. This question is standard in competitive examination syllabi for Mine Environment.

H2S is the correct answer to “Stink damp is synonymous with”. This question is standard in competitive examination syllabi for Mine Environment.

in deeper mines is the correct answer to “When the effect of surface temperature on natural ventilation will be less or negligible”. This question is standard in competitive examination syllabi for Mine Environment.

60 is the correct answer to “In ambient air of industrial area, the permissible concentration of particulate matter less than 2.5 μm size measured on 24 hours average in μg/m 3 is”. This question is standard in competitive examination syllabi for Mine Environment.

mechanical efficiency is the correct answer to “It is the ratio of the power actually absorbed by the impeller and converted into the head of the power applied to the shaf”. This question is standard in competitive examination syllabi for Mine Environment.

11 is the correct answer to “The temperatures in upcast shaft & downcast shaft are 40°C & 30°C respectively. Shaft is 350 m deep. Find the height of motive column”. This question is standard in competitive examination syllabi for Mine Environment.

class C fire is the correct answer to “CO 2 is treated as best extinguisher for”. This question is standard in competitive examination syllabi for Mine Environment.

reynolds number is the correct answer to “The nature of flow of a fluid is governed by a dimensionless parameter called”. This question is standard in competitive examination syllabi for Mine Environment.

Differences in air densities in upcast and downcast shafts is the correct answer to “Natural ventilation can be caused by”. This question is standard in competitive examination syllabi for Mine Environment.

270 is the correct answer to “During hard work e.g. shoveling, tramming, the metabolic heat rate (W m -2 ) from the body surface of an average person is in the range of”. This question is standard in competitive examination syllabi for Mine Environment.

inversely proportional is the correct answer to “What is the relation between size of coal and total methane gas content emitted at face”. This question is standard in competitive examination syllabi for Mine Environment.

the ratio of the input head to Euler's head is the correct answer to “What do you mean by vane efficiency”. This question is standard in competitive examination syllabi for Mine Environment.

250 mg/L is the correct answer to “The permissible value of BOD in the effluent discharge from a coal mines is”. This question is standard in competitive examination syllabi for Mine Environment.

40 is the correct answer to “In blasting operation, generally 1 Kg of explosive liberates how much litre of CO at STP”. This question is standard in competitive examination syllabi for Mine Environment.

difference between absolute pressure and atmospheric pressure is the correct answer to “What do you mean by gauge pressure”. This question is standard in competitive examination syllabi for Mine Environment.

accumulation test is the correct answer to “Which of the following test is better to carry out before cap test”. This question is standard in competitive examination syllabi for Mine Environment.

4.1 is the correct answer to “The BOD 5 of an effluent from a coke oven plant is 25 mg/L, and the effluent discharge is 4 ML/d. The receiving stream has a BOD 5 of 2 mg/L and the stream flow is 40 ML/d. What will be the BOD 5 in the stream just below the mixing zone”. This question is standard in competitive examination syllabi for Mine Environment.

145 is the correct answer to “A waste water effluent has BOD 5 of 80 mg/L and the reaction rate constant is 0.16 per day. The ultimate BOD in mg/L is”. This question is standard in competitive examination syllabi for Mine Environment.

CaCO3 and MgSO4 is the correct answer to “Precipitation of metallic ions in mine water drainage is carried out by”. This question is standard in competitive examination syllabi for Mine Environment.

4.0 is the correct answer to “Mine water flowing at 1.5 m 3 /s with 2 mg/l dissolved oxygen, joins river water flowing at 7 m 3 /s containing 6 mg/l dissolved oxygen. The saturated value of the dissolved oxygen in the mixture is given to be 9.3 mg/l. On the basis, the initial oxygen deficit of the mixture in mg/l is”. This question is standard in competitive examination syllabi for Mine Environment.

85 dBA is the correct answer to “The noise level at 10 m from a long conveyor belt was 95 dBA. What is the noise level at 100 m”. This question is standard in competitive examination syllabi for Mine Environment.

31 Pa is the correct answer to “A mine airway 2m wide, 2.5m high and 500m long. The airway passes a quantity of 8m 3 per second. Calculate its pressure loss? Assume k = 0.0098 NS 2 m -4”. This question is standard in competitive examination syllabi for Mine Environment.

92.3%, 89.4 is the correct answer to “A worker is exposed to 86 dB for six hours and 92 dB for three hours, giving a nine hour working day. Determine the dose % and TWA.”. This question is standard in competitive examination syllabi for Mine Environment.

10 is the correct answer to “In a surface mine, sound pressure level at a location generated by operation of a dozer and a drill respectively are 80 dBA and 60 dBA, when operated independently. The sound pressure generated by the dozer compared to the drill is higher by a factor of”. This question is standard in competitive examination syllabi for Mine Environment.

0.316 is the correct answer to “If velocity of air in a settling chamber is 0.3 m/s, terminal velocity of the particle is 0.19 m/s then find out h/I ratio of the chamber assuming eddy factor 0.5”. This question is standard in competitive examination syllabi for Mine Environment.

850 cm3 per hr is the correct answer to “A miner when doing hard work at 307 K may sweat at the rate of”. This question is standard in competitive examination syllabi for Mine Environment.

2.95 × 10-5 is the correct answer to “A spherical droplet of water, with density 1000 kg/m 3 and diameter of 1 μrn, is falling in air. The viscosity of air is 1.85 × 10 -5 kg/m.s. Neglecting air density and assuming that the settling of droplet in air follows Stokes' Law, the settling velocity in m/s is”. This question is standard in competitive examination syllabi for Mine Environment.

0.8 is the correct answer to “A single lamp placed centrally at the roof provides 40 lux illumination vertically below, at the floor of an underground workshop. The workshop of dimensions 20 m × 20 m with height 4m. Assuming uniform spherical dispersion of luminous intensity, the floor level illumination in lux at any corner of the workshop is”. This question is standard in competitive examination syllabi for Mine Environment.

91 is the correct answer to “At a surface mine office the independent Sound Pressure Level (SPL) measured in dB(A) on account of 3 drill machines are 85,88 and 85. If all the three machines work simultaneously, the combined SPL, in dB (A) is”. This question is standard in competitive examination syllabi for Mine Environment.

7.00 is the correct answer to “A filament bulb produces 30 lux illumination at point A as shown in the figure. Assuming that no other source of lighting present in the roadway, the illumination level in lux at point B will be”. This question is standard in competitive examination syllabi for Mine Environment.

2617 J is the correct answer to “A fan ventilating a heading through a duct of 750mm diameter circulates 5m 3 s -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 3kW.”. This question is standard in competitive examination syllabi for Mine Environment.