Adamantite Drill

It digs nothing the previous tier cannot already dig. Mythril and orichalcum tools already reach every ore in the game, so the bars spent here are bars not spent on armor or a weapon, which is where this tier actually matters. Make it only if you are swimming in ore and want the speed.

Drills are quicker with no buffs but ignore mining speed bonuses entirely, and they reach a tile less. Once a mining set and potions are running, the pickaxe overtakes it and the shorter reach becomes a nuisance around ore veins. For fast blind tunneling with nothing active, the drill is still the better tool.