| As the coal was worked, large cavities were left which filled with firedamp. |
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| Eruptions of natural gas were observed from very early times and the dangers of firedamp in mines were soon realized. |
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| They went down the pit and were vulnerable to explosions of firedamp and coal dust, to rock falls and inrushes of clay, sand and water. |
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| Underground in caves there was never really much need for running unless careful planning failed and a shaft fell in, or a patch of firedamp or bad air turned up. |
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| If the percentage of firedamp starts to rise, less oxygen is available in the air and combustion is diminished or extinguished. |
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| There is no restriction on the air entering the lamp and so if firedamp is entrained it will burn within the lamp itself. |
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| Indeed, the lamp burns brighter in dangerous atmospheres thus acting as a warning to miners of rising firedamp levels. |
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| He reasoned that a lamp in a chimney could create a sufficient updraft that firedamp would not penetrate down the chimney. |
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| Davy however performed his experiments with samples of firedamp collected from pits. |
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| If firedamp is drawn into the flame it will burn more brightly and if the proportions are correct may even detonate. |
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| Like a Clanny, and the Davy before it, it acts as an indicator of firedamp, burning more brightly in its presence. |
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| Later models had graduated shields by which the deputy could determine the concentration of firedamp from the heightening of the flame. |
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| Rusting of the gauze quickly made the lamp unsafe, and the number of deaths from firedamp explosions rose yet further. |
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| Five days after the accident communication was possible and the rescuers worked in darkness to avoid the risk of a firedamp explosion. |
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| Providing fresh air and removing firedamp from pits with a single shaft was a problem as explosive gases accumulated. |
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| In the first half of the 19th century there were many disasters, many caused by firedamp and inadequate ventilation. |
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| Such an incident occurred at Nicholson Pit in 1856 on a lamp being used by an overman to test for firedamp. |
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| Coal mining was very dangerous owing to the presence of firedamp in many coal seams. |
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| Most of the explosions were caused by firedamp ignitions followed by coal dust explosions. |
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| The presence of coal dust in the air increased the risk of explosion with firedamp, and indeed could cause explosions itself. |
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| Such accidents were usually initiated by firedamp ignitions, the shock wave of which raised coal dust from the floor of the mine galleries to make an explosive mixture. |
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| Upon detecting firedamp the candle is lowered and arrangements made for the ventilating of the area or the deliberate firing of the firedamp after the end of a shift. |
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| Firedamp explosions continued, often setting off coal dust explosions, so casualties grew during the entire 19th century. |
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