Mine Ventilation MCQ
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The main fan operating point of a ventilation system is shown in the figure below. If an NPV of 200 Pa assists the ventilation system, the resultant pressure (Pa) and quantity (m<sup>3</sup>) generated by the<br><img src="/images/question-image/mining-engineering/mine-ventilation/1682429211-M2-3-73-95.PNG" title="Mine Ventilation mcq question image" alt="Mine Ventilation mcq question image">
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Air of 20.8% O<sub>2</sub>, concentration enters a coal mine panel at 20 m<sup>3</sup>/s and exits with 20.6% O<sub>2</sub>. The oxygen depletion is due to oxidation of carbon in spontaneous heating process only, assuming the density of oxygen as 1.3 kg/m<sup>3</sup> and the calorific value of carbon as 34 MJ/kg, the heat generated in kW from the panel due to spontaneous oxidation is
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Mean air temperature of a 450 m deep downcast shaft is 29°C and that of the upcast shaft is 37°C. The height of the motive column in m is
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Geothermic gradient is
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Air at a density of 1.2 kg/m<sup>3</sup> flows in a straight duct such that the velocity at the centre is 12.5 m/s. the method factor for the velocity profile is known to be 0.80. The air flow encounters a symmetric expansion such that the cross- sectional are of the duct becomes double. The static pressure value at the inlet and outlet of the expansion are 60 Pa and 90 Pa respectively. Neglecting friction the shock pressure loss on account of expansion in Pa is
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In a mine between upcast shaft and downcast shaft, two airways are connected in parallel and their resistances are 100 and 120 Ns<sup>-2</sup>m<sup>-8</sup> respectively. The resistance of upcast shaft, downcast shaft and the fan drifts are 10, 20, and 5 Ns<sup>-2</sup>m<sup>-8</sup> respectively. The fan drift air pressure is 15 MN/m<sup>2</sup>. The rate of airflow through the mine in m<sup>3</sup>
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In order to estimate the NVP in a mine, measurements are made at the main fan as shown below.<br>
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Air samples collected from the intake and the return gates of a retreating longwall face show methane concentration values of 0.1% and 0.8% respectively. The production from the longwall face is 2000 tonne/day and the air quantity circulating the face is 15 m<sup>3</sup>/s. The rate of methane emission in m<sup>3</sup> per tonne of coal produced is
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The wet kata for light manual workers is
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Which one of the following composition of methane in air is most explosive in nature?
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Explosibility of H<sub>2</sub> by volume is . . . . . . . .
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A sealed area known to have black damp has 18% O<sub>2</sub>, 2% CO<sub>2</sub>, and 78% N<sub>2</sub>. If fresh air has 21% O<sub>2</sub>, 0.03% CO<sub>2</sub> and 78.97% N<sub>2</sub>, the percentage of black damp in the are is
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A mine ventilation system consists of two splits A and B with resistances of 0.8 Ns<sup>2</sup>m<sup>-8</sup> and 3.2 Ns<sup>2</sup>m<sup>-8</sup>, respectively as shown in figure. Trunk airways have resistance of 0.2 Ns<sup>2</sup>m<sup>-8</sup>. The main mine fan is generating pressure of 500 Pa.<br><img src="/images/question-image/mining-engineering/mine-ventilation/1682427077-M2-3-65-87.jpg" title="Mine Ventilation mcq question image" alt="Mine Ventilation mcq question image"><br>The air quantities in m<sup>3</sup>/s circulated in the splits A and B respectively are
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When CO reacts with haemoglobin it changes in to . . . . . . . .
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Which one of the following is used as a reviving apparatus in u/g coal mine?
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A main fan of a mine circulates 40 m<sup>3</sup>/s of air at a pressure of 500 Pa. the mine has two splits of equal resistance. The trunk airways have a total resistance of 0.2 Ns<sup>2</sup>/m<sup>8</sup>. When a booster fan is installed in one split, the flow of air in the other splits stops. Assuming that the pressure remains unchanged, the new air quantity flowing through the mine in m<sup>3</sup>/s is
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If the $$\frac{{CO}}{{{O_2}}}$$ deficiency ratio in a mine is 2%, it indicates
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A fan running at 200 rpm develops a pressure of 50 mm water gauge; the fan speed is increased to 300 rpm. the water gauge developed will be
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20 m<sup>3</sup>/s of air flow through a long wall panel having 1000 tpd of production. Between the intake and return of the panel, the firedamp increases from 0 to 0.2%. The rate of firedamp emission is
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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/m<sup>3</sup>, the velocity of the air in m/s is
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In the Coward flammability diagram, the respective percentages of methane and oxygen at the nose limit are
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Bypass valve in a compressed oxygen type self-contained breathing apparatus is meant to
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Effective temperature is estimated from
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Four psychrometric processes P, Q, R and S are shown in the psychrometric chart below. These processes respectively represent
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If the barometric pressure at a place is 'h' mm of mercury, convert into SI units.
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The chemical protosorb used in
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Quantity of air to be circulated to u/g workings where 150 worker employed in a largest shift and daily production 500 te will be
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The early indication of spontaneous heating of coal can be given by
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In a longwall panel, the main gate road is 1000 m long, 4.5 m wide and 2 m high. The gate road is to be used for airflow at the rate of 17 m<sup>3</sup>/s. Considering a coefficient of resistance of airways of 0.01, the pressure in Pa required to maintain the airflow in the gate road is
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A gas mask does not include