Interesting how the temperature with depth increases differently around the world…. … the TauTona Mine (Western Deep No.3 Shaft) in South Africa is currently the deepest mine at just a bit under 13,000 feet and its temperature is only about 140 degrees F.
I second your statement. In 1976 I was in a gold mine in South Africa at a depth of 9,200 feet. The wall temp was 120F. The air temp was about 100F and the humidity was about 90%. Not a fun place to be in.