This is the seventh of ten stories about how coal was mined in North Lanarkshire.
Coal is usually found deep in the ground and for centuries people have gone to great lengths to get it, using ingenuity and taking enormous risks.
Coal fuelled the industrial revolution. It was burned to heat homes, to power steam engines, to make iron. It could also be heated to extract gas and oil. In fact, coal gas used in most homes until North Sea gas was discovered. Scottish coal production grew from 2 million tonnes in 1800 to a peak of 42½ million in 1913.
Lanarkshire was home to Scotland’s biggest coalfield and at its peak in 1910 the county was home to about 200 coal mines.
Advances in steam engine technology allowed mine shafts to go deeper and deeper. Ventilated air naturally took the shortest possible route, so its route through the mine had to be controlled. It was vital that fresh air reach the deepest recesses of the mine workings.
Natural ventilation techniques took advantage the fact that warm air was less dense than cold air and subsequently rises. For several centuries, fire baskets or furnaces were used as heating sources for the ‘upcast’ shaft. The cooler atmospheric conditions in the ‘downcast’ shaft created the air flow needed underground.
In the 1800s it was common for a colliery to just have a single shaft which would be divided by a timber ‘brattice’ or screen to create ‘upcast’ and ‘downcast’ ventilation using the same shaft. However, this limited the size of the mine that could be adequately ventilated. It could also lead to disaster if the only shaft became blocked, as happened at Hartley Colliery in Northumberland in 1862. There, the cast iron beam of a pumping engine broke and fell down the shaft, shattering the timber brattice. The debris blocked the shaft, preventing the miners from escaping and blocking-off their ventilation. 204 men and boys died and the disaster led to a change in the law so that all mines had to have at least two entrances.
The flow of air around the mine workings would be controlled by trap doors. It was common practice for boys to be employed in opening and closing these doors to let coal hutches pass through.
Mechanical ventilation fans could create a more steady air flow through either suction or compression. These fans were located at the end of the ‘fan drift’ which were connected to the upcast shaft. At first the fans were powered by steam engines but these were later replaced by smaller electric motors.