Interesting stuff. I've pondered series of rock with pyrite and oil.... a "while" ago, Burning Cliff was named near Ringstead Bay, Weymouthish after decomposing pyrite ignited oil... I find it rather hard to believe myself, but it's theoretically possible.
Some numbskull had a similar idea to use deep mines up north as a source of producer gas (CO and H2) by setting fire to the seam. The Chinese coal fires contribute about 3% of the world's total CO2 output. Good job the green stuff is busy converting it back.....