If you have a mine on a mountain and some mad wizard goes and lowers/raises the land then I think it is pretty fair to assume that the mine would collapse and be rendered useless

 Was it a mine resource with nothing built on it, or was the tile built on?

 I've cast raise land in multiple beta's on/beside my own cites to make them weird and imposing.. and no building built on a resource has been destroyed. I did test out the new Destroy Land spell on the Altar.. was kinda funny how his capital went to feed the fishies at the bottom of the sea.