UNDERGROUND mine – a mine where coal is produced by tunneling into the Earth to the coal bed, which is then mined with underground mining equipment such as cutting machines and continuous, long-wall and short-wall mining machines. Underground mines are classified according to the type of opening used to reach the coal – that is, drift (level tunnel), slope (inclined tunnel) or shaft (vertical tunnel).
This used to be the primary means of producing coal in Britain, but there are far fewer such mines compared with 25 years or so ago. A sure sign of an active underground mine is the winding gear tower. In Scotland, these are now a part of our industrial heritage.
At one time, there were literally hundreds of “pits”, as they were called. Most of Scotland’s mines were located in the central belt.
Uranium – a heavy, naturally occurring, radioactive element that is refined and used by the nuclear industry to fuel reactors. Uranium is non-renewable, though it is a common metal found in rocks all over the world. Nuclear plants use a certain kind of uranium, U-235, as fuel because its atoms are easily split apart.
Though uranium is quite common, about 100 times more common than silver, U-235 is relatively rare. Once mined, the U-235 must be extracted and processed before it can be used as a fuel. During nuclear fission, a small particle called a neutron hits the uranium atom and splits it, releasing a great amount of energy as heat and radiation. More neutrons are also released. These neutrons go on to bombard other uranium atoms and the process repeats itself over and over again. This is called a chain reaction.
Uranium fuel cycle – the series of steps involved in supplying fuel for nuclear power reactors. It includes mining, refining, the making of fuel elements, their use in a reactor, chemical processing to recover spent (used) fuel, re-enrichment of the fuel material and remaking into new fuel elements.