122
4 Spontaneous Combustion of Coal
Fig. 4.6 a Bitumen dispersed through inertinite cavities; white light. b Fluorescence mode highlighting bitumen. c TEM : I= inertinite; M= minerals; Bit= bitumen. (M. Glikson et al., 2000)
appears from preliminary observations that some coals have higher content than
others. The susceptibility of certain primary macerals and secondary macerals (e.g.
bitumen/tar) to spontaneously combust, and cause of explosions appears to be also
dependant on coal rank.
Concentrations of bitumen appear to be highest at a rank of 0.8–0.9 VRo (Glikson
and Golding 1998). Although previous studies have shown liptinite group macerals
(e.g. exinte) to be highly volatile, and therefore prone to spontaneous combustion and
explosibility (Sanyal 1983), Bowen Basin Permian coals rarely contain more than
1–2% liptinite macerals. Furthermore, our pilot study showed that a Jurassic coal of
sub-bituminous rank with >20% liptinite macerals (exinite and cutinite) posed no
danger to explosibility due to liptinite macerals acting as a cohesive material for the
coal, thus preventing any dust formation.
4 Spontaneous Combustion of Coal
Fig. 4.6 a Bitumen dispersed through inertinite cavities; white light. b Fluorescence mode highlighting bitumen. c TEM : I= inertinite; M= minerals; Bit= bitumen. (M. Glikson et al., 2000)
appears from preliminary observations that some coals have higher content than
others. The susceptibility of certain primary macerals and secondary macerals (e.g.
bitumen/tar) to spontaneously combust, and cause of explosions appears to be also
dependant on coal rank.
Concentrations of bitumen appear to be highest at a rank of 0.8–0.9 VRo (Glikson
and Golding 1998). Although previous studies have shown liptinite group macerals
(e.g. exinte) to be highly volatile, and therefore prone to spontaneous combustion and
explosibility (Sanyal 1983), Bowen Basin Permian coals rarely contain more than
1–2% liptinite macerals. Furthermore, our pilot study showed that a Jurassic coal of
sub-bituminous rank with >20% liptinite macerals (exinite and cutinite) posed no
danger to explosibility due to liptinite macerals acting as a cohesive material for the
coal, thus preventing any dust formation.