Hello. I did a thing.
This is one of my first programs. I began writing it ages ago and I've been the only one using it for several years now.
I think that code became history.
I kept upgrading and upgrading it as I used it over and over again and now it has become pretty complicated. I think it's worth releasing… even though there are thousands of those out here!

This is a tool that has been polished for a long time. If I felt like a feature was missing during the past two years, it must have been built in somewhere… Unless it's no big deal cuz i'm lazy :>
It's supposed to be straightforward, to be simple up and to be able to do one thing quickly and very well.

It's pretty efficient and it's as fool proof as it gets.
It will mine through gravel and through sand, it will avoid or kill mobs, it will place torches if you have some and stop placing them if they run out and get replaced by some blocks, it will make a cobblestone path for you to walk on if it travels above a ravine, it will build a nice little tunnel around itself if it detects a liquid (ANY liquid !) so you can safely walk in it, it will use the items it finds to refuel itself if it conks out…

I think it's pretty cool.

There is zero way to configurate it. Give it torches maybe, give it some fuel if it doesn't have any if you care. You just need to adjust the length of the shafts because of all these chunk loading innuendos. Be careful not to make it go too far or else it'll be unloaded.

Screenshots
Spoiler




Pastebin
Left lane turtle : http://pastebin.com/u2HFvhbh
Right lane turtle: http://pastebin.com/a1aYzpjy

Usage
>turtle on the left
pastebin get u2HFvhbh mining
mining <shaft length>

>turtle on the right
pastebin get a1aYzpjy miningi
miningi <shaft length>

It'll stop if it encounters a block in the main branch, aka, normally the end of the tunnel.