Is anyone else having problems with completely losing the ability to re-dig tunnels that collapse? We made sure to reinforce every wall and build a column in every square of our mine shaft. About a week later we discovered that various sections had caved in. When we tried to re-dig the entrance once you got to a certain level your only option under terraforming was to construct a support column (with open air above). This has frustrated a friend to a point where he is having troubles wanting to play anymore. It seems like every time we log in we have to re-dig a tunnel and this will be the third time we had to re-dig from a different angle to get to the iron ore.
It seems that if we are to go through all of the effort to get the lumber down to the mine and reinforce the mine that it should last more than a week. Honestly if I reinforce the mine I would rather not have to worry about cave ins. I just figured I would bring up this game mechanic and see if other people felt the same about it.