A pit prop or mine prop (British and American usage, respectively) is a length of lumber used to prop up the roofs of tunnels in
coal mine
Coal mining is the process of extracting coal from the ground. Coal is valued for its energy content and since the 1880s has been widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron from ...
s.
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
traditionally supplied pit props to the British market. As coal mining declined in importance and metal supports were used, the term became infrequently used.
Though it was merely a log cut to a particular length, it was classified as a finished product and so got around the extra Canadian tariffs on the export of raw lumber.
Because of the large quantities exported, it is probable many ended up in British
pulp mills.
Most pit props were made from the wood of
spruce trees.
References
Coal mining
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