If you want to protect yourself you'll need Mithril. Unfortunately you won't be able to mine it, because the northern mountain itself know how important it is, and turned all the ore it held into powerful creatures. If you don't wanna die, you'll need to gamble with death. Slay Mithril monsters until you are able to gather 10 chunks.
When Completed:
Good job! This bar have almost no impurity! The tears of our Father Aule are the best metal a Dwarf can Wear! Use it wisely.