Mining around cave entrances?

[Punctilious]

To shorten my journey around a long winding path to my iron seam, I decided to make a short cut by tunnelling through a wall by my mining setup to the cave entrance as it's only about 50 or so squares away. Trouble is, I've mined all that way to find that I can't mine any more near my cave entrance, was this implemented to stop building walls around the cave entrance or something? It's rather troublesome

[cobaltjones]

Yes. You should have started from the entrance.

[Punctilious]

I can mine out? From the entrance?

[cobaltjones]

There's a buffer zone of about 25 tiles out from the entrance. After that you can mine as usual.

[MagicManICT]

was this implemented to stop building walls around the cave entrance or something? It's rather troublesome

Actually, it's there for several reasons. The biggest one I can think of is so that walls are effective around cave entrances.