The basics of the digger are done: there is a pretty functional prototype in our internal dev builds! Here's a short video of the diggers in action:

https://www.youtube.com/watch?v=koa_E3jkuVM

There are still a lot of things that have to happen before the feature can be released in the default branch of the game.

• The interface needs to be improved. It's a pretty complicated feature and it should be a lot clearer how it works and where for example the digger jobs can be placed
  
• Diggers don't store the blocks they've removed yet; the blocks just disappear. They should gather a small amount of blocks, walk to a crate and store it in the stockpile.
  
• Every block is removed at the same speed now. We think it's best if the digger is three times slower than the player. Dirt should be removed quicker than stone.
  
• We're going to add new research that unlocks the digger. The first research should unlock diggers with a ~10,000 blocks cap, and we can add extra tiers that allow you to expand that to a ~1,000,000 blocks limit.
  
• It should be relatively easy to add builders to the update as well, once diggers are fully done. We want to add them to the 0.6.0 update as well. (Relatively simple builders that can build walls or fill an area with grass, no blueprints yet)