Most mines in UK with open access tend to be in more remote areas, if near to populated areas they tend to be sealed up or gated. Aditnow is one of the top sites though for searching for mines in a particular area. The UK has quite a rich variety of mines for different materiels, from metal ores to building stone, limestone for agriculture, slate mines, coal and oil shale mines and other stuff like fireclay and gypsum as well as sand mines.