I have a friend that showed me coal as a freeze proof bedding material. But hard to find inexpensive fine ground coal. Doing some reading on coal slag, a sand blasting media. Any input on this?? Really easy to get locally??

They use coal shale around here, found at the base of coal seem along the road mainly. It's the grayish black flakey looking "dirt".

For my fellow easterners here...the stuff we have around here isnt what the plains guys have. Our stuff will freeze on you, but it does burn better.

I know some guys used to collect the coal cinders off the sides of roads after a snow.