It would catch fire in the Australian outback. Dry, hot, windy thunderstorms would see to that! We have tonnes of natural wildfires, and some are still started by aboriginal tribes as part of their nomadic way of life and spiritual beliefs. It wouldn't last.
In June and July wildfires have been tearing through the arctic destroying insane amounts of forest. Go stack it on the poles and as the temps continue to warm it'll just do the same eventually.
Just throw it into the empty mining pits instead.