In article , Martin
writes
Yes, the Romans mined a lot

The Old
Rhine was the northern frontier of the Roman Empire. It joined the sea
at what was Brittenburg and is now Katwijk due west of Leiden.

Funny - I always thought that Britain was further north than that. And
that the various walls were, at various times, the most northerly
frontiers of Empire.

And I seem to recall that iron ore was mined during the industrial
revolution as well as Roman times? I can't recall when it stopped.

--
regards andyw