Purbeck Mineral and Mining Museum
After the closure of Eldon sidings all clay exports were via lorry. For several years the clay was carried from the mines across the A351 by trains to the "Lorry Drop". It was realised that the lorries could take the clay directly from the mines and the cost of maintaining a railway system avoided. The transhipment buildings were raised to accommodate the lorries beneath them and in the early 1970s the railway system sold partly into preservation and the rest scrapped. Use of narrow gauge railways continued underground at Norden No 6 & 7 mines until all mining operations ceased in 1999.
Geology of Cornwall
The intrusion of the granite into the surrounding sedimentary rocks gave rise to extensive metamorphism and mineralisation, and this led to Cornwall being one of the most important mining areas in Europe until the early 20th century. It is thought that tin ore (cassiterite) was exploited in Cornwall as early as the Bronze Age. Over the years, many other metals such as copper, lead, zinc and silver have all been mined in Cornwall. Alteration of the granite also gave rise to extensive deposits of china clay (kaolinite), especially in the area to the north of St Austell, and this remains one of Cornwall's most important industries.