Today beneath Towneley Park along with clay and sandstone are large amounts of water and a small amount of coal. When Burnley Corporation purchased Towneley Hall in November 1901, they also purchased the mineral rights directly beneath as otherwise the coal would have been taken and the Hall would have fallen down. Coal was taken from beneath the rest of the Park and subsidence occurred there throughout the first half of the 20th Century.
This is a plan for the mineral support of Towneley Hall, signed Wm. Eagle and dated 5th July 1897. The coal seams near the surface such as the Thin Mine and the King Mine had worked since early in the 19th century but had not undermined the Hall. The lowest seam, the Arley Mine, was the most valuable and had been mined at Towneley Pit since 1876, This plan of the Arley Mine shows the Hall is still being supported today by pillars of coal left after the rest of the coal below Towneley Park was worked out.
No coal was taken from Towneley Pit after 1948 but it continued as a pumping pit removing water for another twenty years to safeguard the deeper workings of other pits in the area. It is remarkable that during its lifetime, Towneley Pit probably brought up 5 tons of water for every ton of coal.
There is a common myth that there are hidden passages beneath Towneley Hall that allowed the family to escape capture from the Roundheads in the 17th century and emerge elsewhere in Burnley. At that time Bank Hall was still owned by a Catholic member of the Towneley family and so could have been on the escape route. However, anyone attempting to tunnel to freedom would quickly have found their workings filling with water. After the creation of the National Coal Board in 1947, the tunnels of the Bank Hall and Towneley Pits were connected, so in the 20th century it became true that there were passages joining Towneley with Bank Hall. This photograph from the 1950s shows the tunnel to Towneley deep in the bowels of Bank Hall Colliery.