Sulphides or Pyrites oxidizing so fast it is actually burning.

Very intriguing discover as I was checking out an old mine site. Obviously someone had been working this site in the last few days. The left fresh Pyrrhotite rocks on the surface. Pyrrhotite, an Iron sulphide, oxidises easily. It rained heavily the day before, which probably help out with the oxidation process. When I arrived, I found a rock of Pyrrhotite lay on on the surface smoking. My theory is that it is oxidizing so fast and creating so much heat, that it is basically burning on its own. A bit like natural ore roasting.