Fall through cave floor in Owls nest mine

Large room with all the blue gems turn to your right thr one with the 2 wolves in you need to kill. directly on your right there is a large iron ore deposit next to a floor torch. I started to mine and fell through the cave floor. I told my guildys what happened . I trued to reprauce it abd sure nuff fell through every time tried 5x each time Ipoped up by the ladder by three fingers . happened saterday 3;13 pm central time At Owls nest mine Thanks