I think the abandoned old mine is near the North Com Tower. I have been there before and now I cannot get under the fallen tree. There was an X place that I could stoop to get under, but, now, it is not there!
Can’t go further.
I have a lot of parts, radiator, cooling thing.
Is there another way to get under the ice without getting explosives from the old mine.
Hi, welcome to the forums 
A video would be nice to understand better, but did you try to reload last checkpoint? Sometimes things that need a prompt to appear (like pass down a tree or pass throught a narrow space) don’t appear but you have 2 options:
1- Only the “X” button (or whatever button if you play with other controller option instead of “default”) is missing, but you can do the action anyway (sometimes you need to stay as close as possible).
2- For some strange reason, you can’t do anything and need to reload last checkpoint.
Also, you can try to invite someone to play campaign with you and see if that “fixed” your problem
The X is not there. Yes will try checkpoint. Not sure to make a video. I was hoping there was some workaround or cheat that would let me get under that damn tree.
I’ll be back. Thank you fro responding.