cavelamb himself wrote:

Lew Hartswick wrote:

Don Foreman wrote:

On Thu, 13 Mar 2008 13:06:12 -0700, Gunner
wrote:

http://www.thesun.co.uk/sol/homepage...icle900459.ece

Meanwhile, last I looked anyway, regulations required a fire
extinguisher every 25 feet in a slate mine in Wales. I've never seen
slate ignited, but it must be nasty!

Slate : Metamorphosed shale. ie. clay just how hot would it
have to be to be ignited? Wonder what is flamable in a
slate mine?
...lew...

Also Dust...

Almost any dust is explosive when the mixture is right.

But the original was about a fire extinguisher every 25 ft
and I don't see how those would be of any benefit for a
dust explosion.
...lew...(lets remember the original post in the thread)