Application of CFD Techniques to Assess Spontaneous Heating/Fire during Extraction of Thick Coal Seam Using Blasting Gallery (BG) Method

ABSTRACT

Spontaneous combustion is one of the key issues in the blasting gallery (BG) method of coal mining. Earlier most of the BG panels have been sealed due to the occurrences of spontaneous heating during the extraction of the panel. This research paper describes a study on spontaneous heating/fire mechanism in depillaring panels of thick seam mining using laboratory experiments, calculating goaf ignition temperature, field investigation and computational fluid dynamics (CFD) techniques. The laboratory study, i.e. Proximate analysis, ultimate analysis, Sulphur analysis, CPT study, DSC study indicated that coal is prone to spontaneous heating. The CFD simulation study reveals that spontaneous heating of leftover coal in goaf areas alone cannot be responsible for the fire in the BG panel. It indicates that an increase in temperature of the goaf is proportional to the amount of coal left in the goaf region. CFD study for roof fall in leftover coal in the goaf region along with spontaneous heating establishes that temperature rise in goaf is proportional to roof fall area of the panel. The laboratory, field and CFD simulation study clearly verify that spontaneous heating/fire in BG panel is due to the combination of spontaneous heating in leftover coal, and frictional heat generated due to roof fall.

KEYWORDS:

• Spontaneous heating of coal
• blasting gallery panel
• computational fluid dynamics
• goaf ignition temperature