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One of the challenges of filming underground for Mining Review was the fact that the filmmakers were unable to use electricity to power their equipment. This item explains why, by illustrating one of the profession's major occupational hazards: the presence of methane gas, or 'firedamp'. Sir Humphry Davy's famous mining safety lamp, invented in 1815, was the first serious attempt to address the problem - although still flame, based, the wick was surrounded by gauzes that were designed to prevent any contact with methane. Prior to this, checks had to be carried out by a man carrying a candle, clad from head to foot in wet sacks to prevent himself catching alight. Even by the standards of the profession in general, the job of 'fireman' was unusually dangerous. Though flames (naked or otherwise) had long been banished from British mines, firedamp was still an issue in 1972. The biggest problem, as this item illustrates, was caused by sparks being struck by mechanised cutting equipment inadvertently hitting what the commentary refers to as "incendive rock" - rocks whose properties make it more likely that friction will lead to ignition. Two examples are given: hard pyrites, and sandstone, which contains tiny grains of quartz. As a result, geologists have a vital role to play underground, by identifying problem areas and recommending appropriate action. Those responsible for ventilating mines also have a crucial task in dispersing as much methane as possible. And the centre-piece of the item shows a laboratory experiment to determine under what conditions sparks are likely to arise during routine cutting. It's a sobering look at just how dangerous the job of mining continued to be, even in a technologically sophisticated era. Michael Brooke
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Complete item (3:23)
