Abstract
This paper presents predictive models to determine spontaneous combustion liability of carbonaceous materials (coals and coal-shales) using statistical analysis. The intrinsic properties and spontaneous combustion liability index were determined by testing 14 coals and 14 coal-shales from Witbank coalfields, South Africa. The relationship between these intrinsic properties (obtained from proximate, ultimate and petrographic analysis) and spontaneous combustion liability indices (the Wits-Ehac Index and Wits-CT Index) were established. The influence of the intrinsic properties of coal-shales in relation to coal properties affecting spontaneous combustion has been established using a statistical method. The linear regression analysis indicates better linear relationships between some of the selected intrinsic properties and spontaneous combustion liability index and thus, identifies the major intrinsic factors affecting their liability toward spontaneous combustion. It was found that a definite positive or negative correlation coefficient exists between the intrinsic factors and spontaneous combustion liability. A set of models to predict the spontaneous combustion liability was derived. The best significant correlation along with the most appropriate model as indicated by R-squared values, the coefficient of correlations and standard error was used to predict the incident of spontaneous combustion.
Highlights
The event of spontaneous combustion is the reason for several cases of fires in the coal mining industry
The results for characterisation tests and spontaneous combustion tests carried out on the samples are presented in Tables 2, 3, 4, 5 and 6 respectively
The study interpreted the linear relationship between the intrinsic properties and spontaneous combustion liability index based on the set criterion (Table 1)
Summary
The event of spontaneous combustion is the reason for several cases of fires in the coal mining industry. Self-heating of coal-shales has been reported in the South African coal mines to be capable of starting spontaneous combustion but not the coals alone (Onifade and Genc 2018b, c, d). This incident has been observed in areas such as overburden shales, selected bands of a coal seam, spoil heaps and highwall It is known that coal, roof shales and spoil heaps may become self-heated and liberate heat naturally under favourable weather conditions Sedimentary rocks such as coal and coal-shale, consist of certain amounts of organic matter (macerals) and inorganic materials (mainly crystalline) causing them to likely undergo self-heating leading to spontaneous combustion (Onifade and Genc 2018d). This renders the rock porous to different fluids like water and
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: International Journal of Coal Science & Technology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
