[[Image:Sideshaft.png|frame|right|Side shaft example]]
; You fail to produce anything here. The rock is stone hard. : Occurs on the surface. This means the tile you are attempting to excavate is actually an ore vein. There's nothing to do about it, you simply have to make your entrance on another tile. Note that if you make the entrance one tile below the vein, the tunnel will open right into the vein and cannot be extended until the vein is depleted. The best course of action at this point would probably be to mine out a rock dile next to the one you get this message on.
; The ground sounds strangely hollow and brittle. You have to abandon the mining operation. : Occurs on the surface. This means there's already a tunnel on the tile you're trying to excavate. There's nothing to do about it, you simply have to make your entrance on another tile. Or you could search for the entrance (possibly caved in) to the existing tunnel.
; A dangerous crack is starting to form on the floor. You will have to find another way. The cave shudders from some imbalance. : Think it is caused by undermining previous tile mined above. No fix though mining another wall and therefore changing tunnel direction, on same tile worked.