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.
Borehole Mining (BHM) is a remote operated method of extracting (mining) mineral resources through boreholes by means of high pressure water jets.This process can be carried-out from land surface, open pit floor, underground mine or floating platform or vessel through pre-drilled boreholes. A borehole is drilled from land surface to a desired depth, where then actual borehole mining will take place. 2  A casing column is lowered down the hole.