Fossil wood and spontaneous combustion

[Aurelius]

I've been reading about the potential for lignite to spontaneously combust, which has gotten me thinking a bit. It's mentioned in the Wikipedia page for Lignite, as well as in paper such as this: https://www.sciencedirect.com/science/article/abs/pii/S0010218002005539

 

I sometimes collect pieces of lignite from locations around the UK, if they preserve the shape and texture of the wood. Is there any risk of them suddenly bursting into flames? I'd have thought not, since I've never heard of such a thing happening, but then I suppose not many people collect these bits because they usually fall to pieces after a while (I treat them through soaking in a sugar solution to preserve them).

 

Any thoughts?

[FranzBernhard]

Sure, many coals are prone to spontaneous ignition. But its caused by a slow build-up of heat within a pile. The abstract you linked to says nearly everything:

You need a pile (heat insulation!)

You need, besides oxygen, some moisture.

You need a small grain size, aka high reactive surface.

Conclusion: Don´t worry, be happy with your specimens! (I am also collecting lignite and other coals, nothing happend yet, besides the occasional disintegration ).

Franz Bernhard