List of top Surface Environment Questions on Mine Ventilation Networks

A gradually expanding duct fitted to the outlet of an exhaust fan is known as

In an underground mine, an airflow of \(30\) m\(^3\) s\(^{-1}\) is delivered through a circular opening having a diameter of \(5\) m and a length of \(500\) m. Assuming that there is no change in the surface characteristics, the diameter of the opening, in \(m\), required to double the quantity of airflow at the same pressure loss is . (Rounded off to two decimal places)

In an underground coal mine, the air quantities \( Q_A \) and \( Q_B \) pass through ventilation districts A and B, respectively, as shown, with a pressure drop of \( \Delta P \) across them. The air quantity in district B is to be increased to \( Q_B' \) by installing a booster fan, as shown, without affecting the air quantity in ventilation district A. The capacity of the booster fan \( (P_B) \) can be expressed as

A main mechanical ventilator installed for an underground mine develops a pressure of 25 mm wg. A natural ventilation pressure (NVP) of 15 mm wg acting in the mine aids the ventilator, and a total 500 \( \text{m}^3\,\text{min}^{-1} \) of air is circulated in the mine. Considering the same NVP aiding the ventilator, the pressure required, in mm wg, to be generated by the ventilator to circulate 1000 \( \text{m}^3\,\text{min}^{-1} \) of air, is . (answer in integer)