How Wales Moved 12 Million Tonnes of Rock to Hide a Power Station Inside a Mountain

Dinorwig in North Wales required 12 million tonnes of excavation across the scheme. The result was a pumped-storage power station built into Elidir Fawr, with tunnels and a cavern large enough to hold its generating machinery. How do you remove that much rock while creating a structure that must remain stable for decades? This documentary follows the excavation, the underground spaces and the water route between two reservoirs, explaining why storing electricity can mean moving water uphill. The scale figure covers the scheme as a whole, not just the machine hall. #Engineering #Construction #BritishEngineering