Actually you bait trolls to do the mining for you. If you run them around tin/copper nodes and pause long enough at the right spot so they attack you then those attacks will crack the nodes open. Kill troll. Collect ore.

It can take a bit longer as you need to find trolls, lead them to nodes and then run them around a bit, but it works.

Finding iron and silver becomes a bit more of an issue, but both can be located and mined since you will have been able to make a bronze pick.