The Gill Heads Vein runs from the western branch of Trollers Gill for 1330 yards across Mosshill Sike Allotment. The course of the vein from the side of the Gill is marked by a line of ancient openworkings.
The mine was originally a lead mine but was later reworked for fluorite.
The obvious large entrance on the bank of Trollers Gill is the Middle Level a decline was driven from it in the early 1920s and stoping done for fluorite but by 1`925 it was uneconomic and the mine closed.
It had three short working periods after that in the 1970's and 1980's but finally shut in 1981 when increasing amounts of calcite in the vein made it uneconomic once again.