Powered tools that hit 0 dura in SSP are disappearing for me. I don't know why, but I would like to inquire if there's a fix or not. 
Or if anyone else is having this issue. It's not old files that java has kept, I've completely wiped my minecraft folder and then installed IC 7.16 + other misc. mods.
Mods installed:
Modloader
ModloaderMP
TooManyItems
Buildcraft
IndustrialCraft
Recipe Book
Floodgate
Pfaeff's Mods
Shelf
Elevator
(Only IC and the ModLoaders were installed directly to the jar)
Edit: appears to be the Mining Drill specifically. The Diamond drill doesn't break apparently. o.o