The Great Orme is a headland on the north coast of Wales.
When part of the summit area was being cleared for a country park in the 1980s, ancient mineshafts were found.
Excavations showed these were very old.
Tools made of deer antlers were found, which had been left by the miners.
Carbon dates showed the mines were operating from around 2000 BC to around 1000 BC, so they are Bronze Age mines.
What were they mining?
A copper ore called chalcopyrite.
It would have been smelted to extract copper.
Copper mixed with tin makes bronze.
Bronze axe heads were a big improvement on stone axes.