Re: air blowing out of an old mine

[Chuck Britton <britton@odie.ncssm.edu>]

> Near my brother's house in Tonopah, NV, is an entrance to an old mine from
> which a strong stream of air exits.  I tried to tell him that it must blow
> out in the daytime and in at night as the mine "breathes" due to
> temperature fluctuations.  But the fact is it blows out all the time!  He
> says there are miles of interconnected tunnels and his opening is probably
> at highest elevation.  What's the explanation?
>   Crawford

There are many 'breathing' caves. The one I know best is near Williamsville
VA. It's breathing is NOT a day/night temperature thing. Someone described
it as a Helmholtz resonator effect but I don't have measurements of
internal volume and connecting 'neck' dimensions to back it up.

I did visit a cave in Tennessee that had your 'constant' flow. In at the
lower entrance and 'out' at the upper end. Perhaps it is related to prairie
dog tunnel ventilation?? I seem to remember a SciAm article on such within
the last 30 - 40 years. ;-)

It's no accident that stressed		Chuck Britton
spelled backwards is desserts.		britton@odie.ncssm.edu