I would imagine that chris_49's explanation is correct. When I used to go down the pit
you were paid extra if you carried a lamp, which by then was supplied by the N.C.B. Most
miners
didn't because they were heavy and always getting in the way especially when crawling
through small openings. You also needed to know how to read the flame which could warn
you of Methane gas. If the light went out you had to find a deputy to relight it as you were
not allowed to do it yourself. In those days a deputy would go first onto the workings and
test for gas especially in the roof cavities where the gas was most likely to build up. The
workers were not allowed to enter a district unless the deputy gave the all clear. I have
a certificate of my grandfathers from the Mine owner giving him the job of shot firer i.e
placing and using explosives and one for deputy with the responsibility of testing for gas.
.
Before safety lamps a man would go into
the workings before the men. He would be clothed in wet leather and carry a long pole
with a lighted candle on the end
hoping that the gas wouldn't be in large quantities
and small amounts would burn off or explode with minimum damage. I wish I could go
back and ask my grandfather if that is what he used to do or if he used a safety lamp.