Fluorspar workings, likely situated on the Slitt Vein, are located on the eastern side of Park Burn, between Rigg Mine and the boundaries of Heights Quarry. An aerial photo at a scale of 1:10,000 of this site reveals intriguing details—the path of the Slitt Vein is prominently visible as it traverses through Slitt Pasture, West Rigg, Rigg, and Park Burn workings. It then extends across the front of Heights Quarry and along the northern side of Weardale, passing above the location of Cambokeels Mine.

1906-1907 Thomas Middleton 1908 W. Hird 1909-1923 W. Hird, Waistell & Co. 1938-1948 A. Dalton