Frongoch Lead Mine is an extensive and important lead mine complex, first recorded in 1759 and last noted as a potential going concern in 1903. It was supplied with water for power and processing purposes from at least five reservoirs in the late nineteenth century: Pond Rhos-rhydd (SN 7045 7595), 2.3km to the north west of the mine, with Pond Glan-dwgan (SN 7070 7515) adjacent to its south; Llyn Frongoch (NPRN 32235; SN 7215 7535), 1km north of the mine, with the subsidiary Blaen Pentre Pool (SN 7235 7487) adjacent to its south; and Ty'n-y-bwlch Pool (SN 7285 7470), some 800m to the north east of the mine.

In 1899 a Belgian firm, the Societe Anonyme Metallurgique, of Liege, took over Frongoch Mine and set about installing new electrically-driven plant. Power was supplied by a Pelton wheel and steam engine in a power house (NPRN 407230) adjacent to the road about 1.6km to the west. A five level dressing mill (NPRN 33870) was built on the (by then) closed Wemyss Mine (NPRN 33907) and this was served by a 700m-long tramway from Frongoch.

RCAHMW, 07 January 2008.