1. A tunnel in a mine is 951 m in length and has a cross-sectional area of 25 m2 and a perimeter of 20 m. If the friction factor for the airway is 0.014 kg/m3, determine the resistance of the airway.
2. A straight 5 x 4.5 m mine tunnel is 453m in length. If this tunnel is shotcrete lined, determine the resistance of the tunnel. If 70 m3/s of air is passed along this tunnel what would be the pressure drop along the tunnel.
3. A straight 5 x 5 m tunnel is 1200m in length and is roughly blasted, determine the airway resistance.
4. Measurements from a ventilation survey indicate that along a particular tunnel a pressure drop of 0.24 kPa for a flow of 35m3/s. If the tunnel is 304m in length and is a 4.5 x 3.7m airway what is the friction factor of the tunnel?
5. A 4 x 3 m rectangular tunnel is 450m in length and contains a single right angled bend with a centre-line radius of curvature of 2.5m. The tunnel is unlined but is in good condition with the major irregularities having been trimmed away. The tunnel is required to pass 80 m3/s of air with a density of 1.25 kg/m3. Calculate the airway resistance and the frictional pressure drop.
6. Determine the equivalent length for a sudden contraction in a mine airway from a cross-sectional area of 20 m2 to 15m2 assuming that the perimeter of the airway remains unchanged at 16m. Assume k = 0.01 kg/m3.