I have not tried the max amount of blocks, but It shouldn't be a problem.
The really important thing is to dig within the colony area or close to it.

Regarding the ? mark it may be due to several reasons. For example, if the colonist is digging a block that doesn't have a icon, that can be a block from a mod or something like a vein of copper ore.

whats the maximum ammout of blox i can mine, cause i tried it and it show the question mark above their heads (( ? )) so if its not like i choose over max,

Thanks dude. Gonna give er' a whirl.

To use it you must first subscribe to the mod to install and activate it in your world.

Once you are in the game with the mod activated in the "Command tool" in the "Construction" optin there is a new button which is the Tunnel Digger.

What Tunnel digger does is that you select where to start digging and you get an interface to choose the direction and how many blocks to dig.

Forgive me, but how does this one work?