Management of spontaneous combustion for metalliferous mines

Spontaneous combustion of mine waste is usually associated with coal mines. It occurs to a lesser extent
with ore deposits that contain pyrite (FeS2) and carbonaceous materials. Limited research has been
conducted into the prediction of spontaneous combustion and currently no single method exists for all
mine sites. Prediction requires classification of the material based on geochemical properties which may
be coded into a block model. The potential spontaneous combustion materials are managed accordingly to
minimize atmospheric oxidation and contact with water.
Spontaneous combustion results in the production of heat (>270ºC near the surface and up to 1,200 ºC
deep in a Waste Rock Dump; WRD), which has implications for; inter alia, blasting while in the pit and the
release of hazardous gasses such as sulfur dioxide (SO2).
Spontaneous combustion often evolves and material can be classed according to stages of development,
including: potential, current and extinct. The “potential” class includes material that has the geochemical
properties that, under field conditions could lead to spontaneous combustion, but has not yet started
reacting. “Current” spontaneous combustion materials have already begun to combust and therefore
prevention is no longer an option; rather the material requires remediation and containment. Zones of
“extinct” spontaneous combustion materials are usually associated with precipitated minerals which may
contain elevated metal concentrations that need to be managed. Several metalliferous mines in Australia
have issues with spontaneous combustion occurring within the pit and on WRDs. These mines have
implemented a number of control techniques that can be incorporated into WRD design and mine
planning to minimize the effects of spontaneous combustion and ultimately prevent it from occurring.
This paper describes some of the control measures that are being implemented for one Australian
metalliferous mine.

Landers, M. and B. Usher. 2015. “Management of spontaneous combustion for metalliferous mines,” in 10th International Conference on Acid Rock Drainage and IMWA Annual Conference, April 20-25, 2015, Santiago, Chile.