NSW Coal Mining.

[John]

Amazing how different countries cope with safety. As one who served his time as an electrician with the NCB during the 1960's, I ended up "down under" in the NSW coal industry.
Whereas in UK pits every piece of electrical equipment was flameproof or intrinsically safe, even in intake roadways and the downcast pit bottom. In NSW, only areas designated as hazadous are equiped with flameproof equipment, ie within a certain distance of a working face, or ALL return roadways.
Funny thing, is it worked! One exception is mines deemed gaseous, where all areas are designated as hazadous.

[John]

One of the other regulations NSW has that the UK doesn't, is when the main ventilation fan powers is disrupted, all power is removed from underground automatically.
I remember when I was surface electrician at Angus Place Colliery in the western coalfield of NSW, when we had lightening storms, a nearby strike would destroy the "remote" diode in the earth continuity circuit for the main fan, which was situated about a half a mile away in the bush! The diode was situated in the winch room at the top of the drift. First I knew about it was when I got the phone call from UG, "what was the power off" and what was wrong with the ventilation!

A few minutes, change the diode, call the shift Under Manager to get permission to start the fan and restore all underground power.