Overall Metallurgy is far better than Mining. Mythril Mines is obviously better for Mythril ore, which you'll need a lot later.
Quote from Bankai231;2897:
So if I should do metallurgy should I get it on an elf alt? I heard people only do it on an elf alt.
Using alts means you don't waste inventory space/ ap and dont get DEX from metalurgy (which is a good thing)
Elves simply run faster