The Diamond Drill is a tool added by Industrial Craft 2. It's an upgraded version of the Mining Drill; like it, it replaces both the pickaxe and the shovel in use, but requires recharging. Like the Diamond Pickaxe versus the Iron Pickaxe, the Diamond Drill can mine blocks that the regular Mining Drill cannot. The Diamond Drill also uses slightly more EU per block mined than the Mining Drill, at 80 EU per use.
The Mining Drill can be charged in any generator, BatBox, MFE, MFSU, or any of the three tiers of Charging Bench. It can also be charged automatically by having a BatPack or LapPack equipped in the Torso slot of your inventory, or charged manually by having an RE-Battery in your inventory and right-clicking.