Heaps of coal known as bings that are left over from industrial mining can self-ignite many years after they are formed and burn slowly for years afterwards, leaching chemicals and gases into the environment, and raising the risk of landslip.
To assess how best to cope with such hidden risks, engineers from Strathclyde University (Glasgow, Scotland) and Edinburgh University (Edinburgh, Scotland) have used temperature probes and a thermal imaging camera to study a burning bing at Bogside, North Lanarkshire in Scotland.
The 30-m-high waste heap began smoldering in 2009, some 80 years after the pit from which the coal was extracted had closed.
Using the equipment, they identified and mapped three well-defined zones: one that was undisturbed by the fire, one in which combustion was taking place, and one that was being heated by the fire.
They were then able to discover how the fire took hold and spread, and pinpointed channels within the heap that deliver air to fuel the smoldering.
The engineers' research was presented at the Geological Society of America Annual Meeting in Minneapolis, MN. More details of the work are available.
-- By Dave Wilson, Senior Editor, Vision Systems Design