I recently came across a mod in the forums while looking for some new mods to try out and I stumbled upon a true gem. Buildcraft is a mod that adds pipes, mining wells, quarry's and fillers. You construct the machines using gears and tools to create machines that will dig materials for you! not only that but you can set up pipes to lead materials from the machines directly to a chest which can them be transferred and filtered into furnaces and crafting templates to make any item automated!
The mod adds a lot of fun to the game and its easy to install!
Source - Minecraft Forums