Here is a quote from 727sky about the
ambient temperatures underground ...
"At only 2 miles below the surface the temperature of virgin rock is around 140°F.
Yet here we have stories of 5 mile deep caverns and people walking around ??
great stories which used to be told around the camp fires to the kids..
Without some kind of super ventilation and air conditioning system our fearless
explorers would be barbecued flesh on the cavern floor after they became
affiliated and passed out from all the noxious gases IMO.
Ask anyone who works on deep wells (less than 20,000 feet = 3.788 miles) what
type of temperatures they reach down hole which can melt all kinds of useful
things used to drill without a continuous supply of cool lubricating mud/fluid.
Like I said great story and much research you have obviously done...
but without pics (video would have been nice) and a depth and temperature
gauge I can't buy it.
The shallow ( 300 metres (980 ft) below the surface in Naica, Chihuahua, Mexico)
........ Even at that depth the Giant Crystal cave is extremely hot, with air
temperatures reaching up to 58 °C (136 °F) with 90 to 99 percent humidity
....... which means normal people can only stand the temperatures for about
10 minutes or run a real risk of vapor locking.
These supposedly underground caverns discussed in the Op are 5 miles deep;
THINK.. No doubt there are many deep caverns but I can guarantee you
there are not people walking around without some sort of well air conditioned
environmental protective suit.."
So maybe not 5 miles deep , but five miles IN ...
I mean HOW would they measure their depth ?