The low-grade coal which is the inevitable waste product from coal-mining operations accumulates in huge heaps in coal-mining districts. Bushfires and long periods of sustained high temperatures can ignite these heaps, which then smoke for many years and pollute the environment with unburnt hydrocarbons and sulphurous smoke.
The film gives a scientific assessment of the problem and shows a series of experiments aimed at developing methods to control the burning dumps. It concludes with recommendations for the proper construction and chemical treatment of coal waste dumps.
Produced in 1970.