Roger Chapman wrote:
dennis@home wrote:


"The Natural Philosopher" wrote in message
...

You don't have to find geologically active bits dennis.

Go down any coal mine - below a mile its about 30C plus

Does not compute.. go down a cave, its nowhere near 30C.
Mines have stuff in them that warms them up, people, machines, etc.

I am intrigued. Caves with a vertical depth of more than a mile, where
in the world is that? But perhaps more pertinent to temperature at depth
where in the world will you find an unflooded cave below local sea level
let alone a mile below.

fascinating article here.

http://www.eoearth.org/article/The_C...of_Coal_Mining
At a mile below ground, temps of 120F.