Using Fire to Ventilate an Underground Coal Mine.
Up until steam driven surface fans were introduced widely in the early 1900’s, ventilation was often provided by the use of a fire
The first ventilating furnaces of that 17th and 18th Century were built on the surface but it was soon realized that burning coals suspended in a wire basket within the upcast shaft gave improved ventilation. Furthermore, the lower the basket, the better the effect.
This quickly led to the construction of shaft bottom furnaces.