Miner's Lamp Geocoin (Dark)

The original mission was about shedding light in dark places. But now perhaps it symbolises the end of the coal industry?

This coin used to travel but now it associated with an EarthCache in my hometown.  This cache looks at the history of coal and its exploitation

The Weirdest Trees and “ glo caled”. | GC8KP43 | South Wales, United Kingdom

The museum is a great place to look at the history of coal and its cost.

The Flame Safety Lamp. THIS IS A REPLICA OF AN IMPORTANT CULTURAL AND INDUSTRIAL ARTIFACT IN WALES The danger from explosions is ever present in coal mines. Ignition of naturally occurring methane gas can be disastrous. This gas is known in the pits as "firedamp", a mixture of methane gas and air. Methane (CH4) is odourless, tasteless, colourless, and lighter than air . Early coal mines were troubled by methane gas; the coal mine management paid someone to disperse the gas by igniting it with a naked flame.

As you can imagine this was a very dangerous occupation and these "firemen" literally risked their lives every time they entered a gaseous area of the mine. Fireman is widely known as an official of the mine in many area's, even today. As mentioned previously, historically he had one of the most dangerous jobs. He walked down roads or tunnels with a candle and ignited any accumulated gases he encountered. He held a long stick with a candle at the end. Naturally this exploded any methane present. His only protection was to wear clothing such as wool, or leather, well damped, and his head protected by a hood (sometimes he was referred to as the 'penitent', because his dress resembled certain religious orders in the Roman Catholic Church). Very often the fireman was killed during the operation of igniting the gas. Inventors worked on developing a flame lamp which could be safely taken into a coal mine without igniting the methane gas present.

In 1815 Humphry Davy invented a safety lamp, George Stephenson, working in a colliery near Newcastle, also produced a safety lamp that year. Both men claimed that they were first to invent the safety lamp. The safety lamp burns oil. Inside the lamp is a wire gauze cylinder of fine mesh which forms a cage around the flame. Heat from the flame is dissipated and this prevents the flame from propagating outside of the lamp. How heat transference in a flame safety lamp is achieved.

1). Convection feeds the flame and cools the lamp.

2). The glass allows radiation.

3). The brass oil vessel uses the principle of conduction and radiation.

4). The two gauzes conduct heat and keeps temperatures low.

5). The steel bonnet conducts, radiates and improves ventilation.

6). The outlet holes in the bonnet top allows convection from the flame and carries the heat away.

The quantity of methane gas present in a particular part of the mine was obtained by switching off cap lights ect. so the mine was in darkness except for the light generated by the oil lamp, holding the lamp up to the roof, lowering the wick, and looking at the colour, size and shape of the flame. If firedamp was present a pale blue flame appeared around the central flame, sometimes referred to as the "blue-cap". The flame safety lamp also detects oxygen deficiency, known by miners as blackdamp, a mixture of air and carbon dioxide (CO_²) which could be found near the floor, usually where the ventilation is inadequate.