As well as unusual places just entered the Kidd Creek Mine in the DB.
"Kidd Creek has three shafts known as the No. 1, No. 2 and No. 3 mines. Mine D is currently being developed to access reserves below the 6,800 foot level. This will be the deepest base metals orebody being mined in the world".
You wouldn't get me down there. 🙂 Then I get a bit dizzy in the underground.
The past is a foreign country: they do things differently there.