Electrically Powered Ventilation Fans
From ETHW
As coal mines continued to increase in size, the dangerous problem of inadequate ventilation became abundantly clear in the disasters at Jacob's Creek, PA (1907), Monongah, WV (361), and Cherry, IL (1909). While steam driven fans, used widely in the late 19th century, were an improvement to the furnaces used to increase circulation in 18th and 19th century mines, it was not until the introduction of electrically powered fans in the early 20th century that dangerously high levels of methane could be controlled and safely dispersed.
