This mine has been incorrectly positioned... It is nowhere near Ivybridge, nor in the Teign Valley. Although, it does state that it's SW, although actually SE of the Village of Ilsington. NGR SX 788 758 (Central).
Simon I have offered a few times to correct information here, but have received no reply.... Again today I've copied all the Dartmoor listed mines and put a grid reference to them, and corrected one or two mistakes that has crept in.
It appears my input, like before is not required.
Tin Miner