Turtles -- you can write or probably find programs that can resume gracefully.
RP2 Bore/Quarry -- You custom build the whole ship. Put it on frame -- block breakers lead the way and motors move it along. You can make them vertical, or horizontal. They run on a redstone and bluetricity. A simple timer can trigger the block breakers and the frame motors. The motors need a little bluetricity each move.
IC2 Miners -- Supply a drill and a scanner (5x5 or 9x9 scanner shape with the miner at the center). Mines a single shaft down, and will get any ores in the scanner range. Fortune on the drill will apply to mined ores, silk touch does not work. Runs on EU.
Steves Cart's 2 -- You can build carts to mine. They have good range... like 3x3, 5x5, and i think the largest is 7x7 or 9x9. and lays its own tracks. Runs on furnace type fuels.
Thaumcraft 3 -- Tunnel bore. Uses the enchants on a pickaxe and a wand and mines a circular tunnel/hole depending on which direction you point it. 64 block range. Fortune/silk touch on the tools will be transferred to the mining beam. Circle is 5x5 by default, but extends up to like 11x11 with wand enchants? Runs on thaumcraft environment energy
BC Mining well -- quickly mines a single shaft down.