Although the main part of Carrock Fell Mine is beneath Carrock Fell, there are some workings to the south of Grainsgill Beck at the base of Coomb Height. A trench runs northward down the slope to the beck, containing a number of shafts and levels. These surface workings follow the line of the Harding Vein, the most productive part of the mine. Carrock Fell Mine was the only British Tungsten mine outside Cornwall and was operated at various times between 1850 and 1982 when the price of Tungsten was sufficient. Although reserves of Wolframite and other tungsten ores are believed to remain, the Harding vein beneath Knott has long been worked out and the levels were used for dumping sludge from ore processing operations.