You might need silver for Frostner, which is very useful weapon to fight goblins (also frost arrows are useful).

But you don't need a crafting base in the mountains! With proper logistics, by which I mean efficient use of teleports, carts and ship, you can easily haul silver to your base.

In our 2 player multi we have just finished a big mountain with 14 (yes, fourteen!) separate silver veins. It took us three silver runs - one short for basic items, second (long) for upgrades, third short for silver to craft 2 Frostners.

Just use portals to get there, rest and repair pickaxes, then haul silver in the cart to your ship. Simple as that.