Main pit is now submerged. Surviving features include ruined buildings, portions of the incline system, and various artifacts—most notably a well-preserved self-contained steam winch. Above the site, the course of the two-pitch incline that once linked the John Robinson tramway with the Nantlle line can still be traced across the landscape. **

Operations at this pit quarry commenced in 1790, and over time it gradually absorbed numerous neighboring workings, among them Allt Llechi, Blaen Cae, Cloddfa Fawr, Cloddfa Onnen Fach, Cloddfa’r Onnen Fawr, Chwarel Coch, Talysarn Bach, Twll Penditch, Twll Penuparc, and Twll Factri. By 1829, the quarry employed both a water balance and a rag-and-chain pump for its operations. Steam-powered chain inclines were subsequently introduced but eventually gave way to Blondin ropeways. The quarry grew to become the third or fourth largest operation in the valley, producing 8,210 tons in 1882 and employing approximately four hundred workers (including those at Ty Mawr), with locomotives serving its internal tramway network. Before the century’s end, however, the quarry reverted to horse-drawn haulage. An incline provided the connection to the Nantlle Railway, though this was later repositioned further south as the workings extended. A cost-saving strategy saw the quarry acquire nearby sites specifically for use as waste tips, which substantially reduced operational expenses. Final closure came in 1946.