Re: air blowing out of an old mine

[David Dockstader <DRDOCK00@UKCC.UKY.EDU>]

Hot bottoms are generally found only in deep mines which go well below any
possible surface opening.  Therefore, there it is very difficult to get this
hot air to participate in any natural circulation.  If the mines had large
open areas some currents due to density instabilities might be possible, but
in the typical shafts not much natural flow exists unless you have multiple
openings to the outside.  Good air circulation in deep mines is difficult to
engineer and expensive, which is why most mines don't have it and minning is
really nasty work.  What we have is the vertical tube of helium with only the
top open.

On Wed, 16 Sep 1998 22:19:01 -0400 Herbert H Gottlieb said:
> But mine shafts are often hotter at the bottom than at the surface.
> Wouldn't the air become heated at the bottom and become
> less dense than the air at the surface?
>
> What happens when you take a vertical tube of helium gas and then
> remove the endcaps?
>
> Herb Gottlieb