Mine Ventilation - Study Mode
[#146] A flammable mixture has 70% CH 4 and 30% CO. The lower flammability limits for these gases are 5% and 13% respectively. For the mixture, the lower flammability limit in % is
Correct Answer
(A) 6.13
[#147] Given the following, Equation/formula/law Application P. Bernoulli equation 1. Pressure loss in laminar flow of fluid Q. Poiseuille equation 2. Drag loss due to regular obstructions in fluid flow R. Bromilow's formula 3. Energy conservation in ideal fluid flow S. Stokes law 4. Terminal settling velocity of fine particles
in fluid the correct match is
Correct Answer
(A) P-3, Q-1, R-2, S-4
[#148] A mine ventilation system consists of two splits A and B with resistances of 0.8 Ns 2 m -8 and 3.2 Ns 2 m -8 , respectively as shown in figure. Trunk airways have resistance of 0.2 Ns 2 m -8 . The main mine fan is generating pressure of 500 Pa. The flows in the two splits are equalized by placing a booster fan in split B. Assume that the fan pressure does not change after installation of the booster fan. The size of the booster fan in Pa is
Correct Answer
(A) 749.05
[#149] Pressure characteristic of a mine fan is given by. P = -0.06Q 2 + 400. where P is the pressure in Pa and Q is the quantity in m 3 /s. The resistance of the mine is 0.19 Ns 2 /m 8 . An identical fan is installed in the mine to operate in series with the existing fan. The new mine quantity in m 3 /s is
Correct Answer
(C) 50.8
[#150] For Indian coal mines, the 'maximum allowable concentration' of respirable dust containing 7.5% free silica in mg/m 3 is
Correct Answer
(A) 2