The Caterpillar is a very resourceful tool to automate digging a 3×3 hole; essentially a tool to start a mineshaft. You can add a few attachments to it to gather materials as well as place blocks as it digs.
It’s very simple to build and greatly streamlines your mining. The Drill base and Drill head are the key components but you’ll want to add an Item Collector, Drill Storage, and a Decoration Placer in order to do some of the more advanced tasks. The collector and storage pieces allow the machine to scoop up blocks as it travels.
And the Decoration Placer will place the necessary blocks to properly navigate your new tunnel. All you need to do is supply the drill with the key items (i.e. rails, torches, wood planks, etc) and the machine will do the rest. Soon your tunnel will look like an authentic mine shaft.
The most important aspects of the drill to keep up on are the fuel source, which is coal, and the drill head. You can give it stone, iron, gold, or diamond drill heads but for longevity and if you can afford it, diamond may be your best option.
It’s truly a fantastic mod to get any mine started and for automating a fairly tedious task. Now your mine can get a jump with rails and supports set up for you to return home to. Just set it and forget it… until it needs restocking of course.