This video shows why you cant always trust all information on the internet, as well as shows the basics of torque wrenches and a few oddball calculations you might run across when building custom things.
Underground mine ventilation. Underground mine ventilation provides a flow of air to the underground workings of a mine of sufficient volume to dilute and remove dust and noxious gases (typically NOx, SO2, methane, CO2 and CO) and to regulate temperature.
WORKSAFE NEW ZEALAND // APPROVED CODE OF PRACTICE // VENTILATION IN UNDERGROUND MINES AND TUNNELS. (d) ensure air provided by the ventilation system at the mining operation. is of sufficient volume, velocity, and quality to remove airborne dust. and contaminants from the mining operation and to maintain a safe.