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Section 3 Read the text below and answer questions 28-40.
A significant development in mining safety
A Coal has been used as a source of fuel for over 5,000 years, but for most of that time it was probably gathered from places where it was exposed on the surface of the ground. It is possible that the Romans undertook some mining, but coal mines across Europe largely date from the 13th century. Thereafter coal production increased steadily and it gradually replaced charcoal and wood as a source of heat and energy.
Initially, coal mines were fairly shallow, but they quickly reached the point where artificial lighting was necessary. At first the lights used would have been no different from those used domestically – candles and simple oil lamps. But as coal mines became deeper, miners encountered a new and terrible problem — firedamp. This was a natural gas, principally consisting of methane, that exploded on contact with a naked flame. The first known major firedamp explosion, which killed 99 people, took place in Belgium in 1514 and as new technology was used to mine at increasingly deep levels, the problem got worse.
B The simplest solution was to improve the ventilation of the mine. Many mines had only one shaft leading from the surface down to the working area below. Ventilation could be improved to some extent by dividing this into a downcast (bringing in fresh air) and an upcast (returning foul air and firedamp to the surface).
But what was really needed was a safe lamp that could not ignite firedamp. The earliest forms of safety lighting sought to produce light without using a naked flame. One early method tried to utilise the fact that skins removed from decaying fish contain the element phosphorus, which emits light in the form of phosphorescence. Unfortunately, this phosphorus is highly toxic, flammable and can self-ignite-hardly desirable properties in a safety light.
An alternative was a device invented in about 1750, consisting of a flint which struck against a piece of iron when a handle was turned, creating a shower of sparks which lit up the surrounding area. These were believed to be too cool to ignite firedamp. This device had major drawbacks — extra manpower had to be used to operate it continuously, and it also required regular maintenance and replacement. But worst of all, it was not in fact safe, and numerous accidents were caused when the sparks ignited firedamp. Nonetheless, it was considered to be the least dangerous form of lighting at the time.
C By about 1810 the problem was becoming acute, and in some cases there was no alternative to working in the dark. Some mines were being forced to stop production, with serious economic consequences for the mine owners and local communities. The general response, however, was to keep going and reluctantly accept the inevitable deaths from ignition of firedamp as a regrettable, but not especially remarkable, consequence of coal mining.
The miners themselves could do little w they were largely illiterate, and depended on the mine owners for a livelihood However, the clerical, medical and legal professions were beginning to take notice. After 92 men and boys were killed in 1812 by an explosion at Felling Colliery in northern England, several professional people took action and a society was set up to raise funds for the discovery of new methods of lighting and ventilating mines. The first report of the society stated, ‘It is to scientific men only that we must look up for assistance in providing a cheap and effectual remedy.’
D As the leading chemist of the day, and an expert on gases, Sir Humphrey Davy was a natural choice from whom to seek help, and he was approached by the society in 1815. The general belief nowadays is that he was the inventor of the first miners’ safety lamp, in which the flame was enclosed by a mesh screen containing very small holes. Air could enter the lamp through the holes, but they were too small to allow the flame of the lamp to pass through them and ignite any firedamp present in the mine tunnels. Davy presented a paper describing the lamp in November 1815, and it was trialled in January 1816.
However, a few weeks prior to Davy’s presentation, an engineer called George Stephenson had independently designed and demonstrated a lamp based on the same scientific principles. After much discussion and argument, he was eventually recognised as deserving equal credit for the discovery, but the time needed for this recognition to be given meant that the miners’ safety lamp had already been called the ‘Davy lamp’ and it is called that today.
E But in fact, the real inventor of the safety lamp was a man called Dr William Reid Clanny, who in 1813 had been awarded a silver medal by the Royal Society of Arts, Manufacturers and Commerce for his own version of a safety lamp. Clancy’s first lamp did not fulfil the needs of the ordinary working miner as it was rather heavy and cumbersome.
But rather than seeking to glory in his achievement, he recognised its deficiencies and continued to work to improve it, as well as sharing his knowledge with others. George Stephenson acknowledged a debt to Clanny’s research, and Humphrey Davy visited him in 1815 shortly before completing the design for his own safety lamp but to this day Dr Clanny remains a forgotten hero.
