What is the relation between size of coal and total methane gas content emitted at face?
Select an option to see the answer and solution.
Mining Engineering · all questionsMine Environment
Mine Environment
practice.
Practice every MCQ with options. Use Show answers when you want the correct option and solution.
51
Questions
2/3
Page
Pick an option on a question to see the right answer and solution.
What do you mean by vane efficiency?
Select an option to see the answer and solution.
The permissible value of BOD in the effluent discharge from a coal mines is
Select an option to see the answer and solution.
In blasting operation, generally 1 Kg of explosive liberates how much litre of CO at STP?
Select an option to see the answer and solution.
What do you mean by gauge pressure?
Select an option to see the answer and solution.
Which of the following test is better to carry out before cap test?
Select an option to see the answer and solution.
The BOD5 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 BOD5 of 2 mg/L and the stream flow is 40 ML/d. What will be the BOD5 in the stream just below the mixing zone?
Select an option to see the answer and solution.
A waste water effluent has BOD5 of 80 mg/L and the reaction rate constant is 0.16 per day. The ultimate BOD in mg/L is
Select an option to see the answer and solution.
Precipitation of metallic ions in mine water drainage is carried out by
Select an option to see the answer and solution.
Mine water flowing at 1.5 m3/s with 2 mg/l dissolved oxygen, joins river
water flowing at 7 m3/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
Select an option to see the answer and solution.
The noise level at 10 m from a long conveyor belt was 95 dBA. What is the noise level at 100 m?
Select an option to see the answer and solution.
A mine airway 2m wide, 2.5m high and 500m long. The airway passes a quantity of 8m3 per second. Calculate its pressure loss? Assume k = 0.0098 NS2m-4
Select an option to see the answer and solution.
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.
Select an option to see the answer and solution.
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
Select an option to see the answer and solution.
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
Select an option to see the answer and solution.
A miner when doing hard work at 307 K may sweat at the rate of
Select an option to see the answer and solution.
A spherical droplet of water, with density 1000 kg/m3 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
Select an option to see the answer and solution.
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
Select an option to see the answer and solution.
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
Select an option to see the answer and solution.
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
Select an option to see the answer and solution.