The Three Mines Challenge was invented by Adrian Pierce, and consisted of Jugholes, Barjarg and Cwm Ystwyth. each mine had a small logo - 3M in a circle - painted somewhere within and you had to take a photo in front of each one. I did it with Colin Faulkner and Adrian Farrel back in 1985, using a (for the time) very fast hired car. I no longer have a record of the time, although I do have a few photos, but speed limits were not really enforced in those days. It would be difficult to better it now. I don't think it was attempted again after that. The painted logos are certainly long gone.