Deep cave

[Muffintop79]

What kind of pickaxe is needed to mine the deep swamp cave and how can i get it??

[Fair]

Deep cave progression goes like this:
Forest/plains -> Snow -> Swamp -> Desert

To mine the rocks, you need the pickaxe made with the ore from the previous cave :)

[Porked!]

To add to that, you can also skip the deep cave progress entirely by going to deep snow and find an Ice Pickaxe. Or, of course, massive amount of dynamites.