Phuket Mining Museum, located in Kathu on the road between Loch Palm Golf Club and British International School, is one of the island’s most interesting museums. It features displays ranging from tin mine models to a recreated scene in an opium den.
A visit with a guide (or someone who has some knowledge about Phuket's history) is recommended as, for now, most of the signs and descriptions are only in Thai. There’s a minimal entrance fee.