Thomas Chapel coal mine had opened by 1843. It is depicted on Ordnance Survey 25inch mapping of 1889 and 1907, which shows various tips, an 'Old Engine House' with an 'Old Shaft' to the east (1889 map) and an 'Old Shaft (Coal)' (1907 map) to the west. The colliery was the northern end of the Saundersfoot Railway (nprn 43052).
Sources include: The Saundersfoot Railway, M R C Price, Oakwood Press, 3rd edition 1978.
RCAHMW, 12 March 2014.