1. Measurements of gas concentration at a particular site underground indicate that the concentration of methane in the general body of the air is 0.85%. If 22.5 m3/s of air is flowing at the site determine the volume of methane present in the airstream?
2. A Pitot-static tube is used to measure air velocity as part of a ventilation survey. At a particular measuring site a velocity pressure of 650 Pa is measured, assuming the air has a density of 1.2 kg/m3 what is the air velocity at that point?
3. Describe the method of undertaking an anemometer traverse for a mine airway
4. Describe the two main methods of undertaking a pressure survey in a mine. What advantages and disadvantages do each method have?
5. Describe a method of undertaking a point measurement traverse for airflow in a circular duct using a pitot static tube
6. What methods are available for measuring the area of a mine airway
7. An explosion occurs when a pre-mixed cloud of gas and air (or other oxidiser) combusts resulting in a rapid increase in pressure. Four conditions must exist underground for an explosion to occur. Name the four conditions and give a brief description thereof.