Non-Minable Squares Following Cave-In

[jksusalla]

I experienced a cave-in in the vicinity of two mine support beams. The beams were constructed during the cave-in, but I suppose I did not place either of them directly under the correct spot. Either way, the supports now seem to be encased in unminable squares. Obviously not the end of the world, but I'm curious if anyone has a suggestion on a way to rectify (as in, please tell me the ways I am being dumb) or if it's a legitimate bug.

[pilgrim]

build another mine support and destroy the ones in the wall. Then you will be able to mine them

[jksusalla]

Thank you kindly!