I spent all weekend Mining, and not much else. I shudder to think how much I could get selling all the ore I mined, much less the shards. Mind you, I started at 13 MIN and finished at 31 MIN, with very few leves or scrolls (4 of each, actually). I also broke to do the Ifrit chain, farm some boar hides, and the MIN quests.

Long story short, if you need money, DoL is where it's at.