The deepest mine is in South Africa (AngloGold Ashanti’s Mponeng gold mine) at a depth of 3.9 km. The get frequent rock bursts and it is very hot and difficult. Fat Boy hasn’t the ability to go anywhere near this deep. Now, the mountain could well be collapsed or a deeper fault could be moving. We’ll have to see if the volcano is a possibility, it doesn’t seem so now.
Fat boy is also very hot and very difficult.