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.
I. Definition (1-3-1) A. Ventilation is the controlled removal of smoke, heat, and gases and the replacement with fresh air. B. Ventilation contributes directly to accomplishment of basic fire fighting objectives by. 1. Reducing danger to trapped occupants and extend time for rescue operations.