Page 118 - Once a copper 10 03 2020

helmet complete with lamp and a battery that fitted to our belts.

We were issued with a metal token known as a ‘Lamp Token or tallie’. These
tallies remain popular as a collector’s item by both museums and the general
public. I still have mine.

The tallies informed colliery
management of who was in work but
became vital when rescue services
needed to know how many men were
underground during an incident such
as a fire or explosion. Colliery check
systems apparently became common
during the late nineteenth century and
became mandatory in 1913 after an Figure 50 Lamp tallies – some of the pits I attended
amendment to the 1911 Coal Mines
Act.

To miners, the dangers of underground mining are serious. Underground
explosions, suffocation from lack of oxygen, flooding or exposure to toxic
gases are very real threats.

To prevent the build-up of gases, methane must be constantly ventilated out
of underground mines to keep miners safe.

Most of the world’s coal reserves are buried deep underground.
Underground mining, sometimes called deep mining, is a process that
retrieves coal from deep below the Earth’s surface—sometimes as far as 300
meters (1,000 feet). Miners travel by elevator down a mine shaft to reach the
depths of the mine, travel on underground trains to operate heavy
machinery that extracts the coal and moves it to the surface.
The cramped cage elevator (ours had room only for four people at most),
made me apprehensive about travelling so far underground, moreso as we
heard the clanking noises the elevators made as it lowered.

As we descended, the supervisor explained that underground temperature
rises the deeper you go. The Geothermal gradient is the rate of increasing
temperature with respect to increasing depth in the Earth's interior. It is about
25 °C per km of depth (1 °F per 70 feet of depth) near the surface in most of
the world.

That explained why I felt myself heating up and it wasn’t due to my growing
sense of claustrophobic panic!

Stepping out of the elevator at the coal face level the supervisor was
descriptive about the conditions. The air he breathes is saturated with the Page118
coal dust, and explains why for a full shift, may of the miners wore a surgical