I have the same problem with quest Vigor Mortis from Naberius ... I had read something about a "crystal skull" in a book ... O, the enemies on the Mine aren't easy to fight!

And despite that when I'm already Level 20 and the enemies are on the Mine about L23 ...
However, this "Mine" you means, is in the Orobas Fjords, isn't it? Or am I wrong?