I'm not aware of any local tin ore mining - Cornwall and parts of Dartmoor Devon were the main ( global) source of tin ore / Cassiterite for a while.

Tin and other minerals had been mined from early man's time. The decline came from the mid 1870's approx when other Tin deposits were found in Australia , South Africa , the Americas etc.

Some FoD folk had gone to Cornwall to mine Tin and Copper etc, likewise there is a flow of Cornish miners to the FoD and South Wales.