Hey! For the drill moving back and forth I just mocked this up in Photoshop. Depending on what game engine you're using and whether it's drawn as a sprite or a background object you need a script or chunk of code that adjusts the drills draw position in a loop to create the back and forth movement.
Tile-able means the drill graphics are semi-modular, you can take different sections of the drill and repeat them or take out some sections to make different sizes and lengths of drill.
Hope this helps!