These two collieries worked the Simonstone coal, which has been tried intermittently over a distance of four kilometres from Sleddale onto Burtersett High Pasture, where it dies out. It was also identified as being present on Bainbridge High Pasture, but there is no evidence of significant working.
The collieries were as follows: Bank Gill (1 level, 1 pit), West Duerley Pasture (2 levels), Storth (5 levels, 2 pits), and Scar Head (3 levels). Storth Colliery was working by the 1790s and the seam was 16 inches (0.4m) thick, with a roof of hard shale and a floor of fireclay, where last worked in 1921.
Gill, M.C. “Great Dales Coalfield, Eastern Areas” British Mining No.86 (2008), pp.68-108
Spensley, I.M. Mines and Miners of Wensleydale, The author, 2014