4. Old Power House (Middle Pit).

The Middle Pit shaft (originally the Ragman pit) was sunk around 1840 and re-named after it was deepened in 1881. It was one of the colliery's main drawing shafts and was used until 1968. Construction of the power house (4) to Middle Pit was begun in 1895. It consisted originally of a small single-storey building, latterly a workshop, which was extended to the north-east with a substantial L-shaped building of two ranges between 1900 and 1903 in order to increase supply as mechanisation intensified at the colliery. The generating equipment, including three turbine generators, was situated on the first floor, while the ground floor contained an engine which powered the underground haulage systems in Middle Pit. There was also an electrical workshop on the ground floor which was used prior to the construction of the main fitters' shop (15) in 1935.