|
This photo shows you the head of a Protego cap. If the pressure
caused by the methane gas in the filled-up shaft gets too high, a valve in the
cap's head will open and the gas can pour out without causing any damage.
Additionally these caps prevent oxygen from getting into the former shafts and
by that reduce the danger of fire in the old roadways, mining areas etc.
underground to a minimum.
©
Jan Bruensing (LEK RWTH Aachen)
|
