A series of precarious working above Llyn Du’r Arddu. Unlikely rumour that it’s linked underground with Britannia.
Publications (5)
- (2010); CATMHS - Newsletter 098-February; 38 pages
- (2011); CATMHS - Newsletter 102-February; 37 pages
- Agnew, J.L. (1989); PDMHS (Peak District Mines Historical Society) 10-6 Win - Hafod-y-Porth Copper Mine, The; 9 pages (359-367)
- BGS - Mine Plans (large, zoomable) - Clogwyn Coch Mine; 1 pages
- Colman, Timothy B. and Laffoley, Nicholas d'A. (1986); PDMHS (Peak District Mines Historical Society) 09-5 Sum - Brittania or Snowdon Mine; 19 pages (313-331)
