Print this pageAbstract: The
Deformation Metamorphism of Tectonic 
Coal
and Its Application in Geological
Mining Hazards
CAO, YUNXING and LIU RUIXUN
Deformed coal is called
tectonic coal which is further classified as cataclastic coal, granular
coal, and mylonite coal. All three kinds of tectonic coal have generated
dynamometamorphism during their deformation period. Compared with normal
coal, their physical and chemical properties changed:
1. The basic structure unit
(BSU) of tectonic coal increased. Compared to bituminous coal, the Lc of
BSU of the tectonic coal increases while La stays constant. Compared to
anthracites, La of BSU of tectonic coal increases while Lc stays constant.
2. The free radical content
of bituminite in the tectonic coal is higher than that of normal coal.
The free radical content of metaanthracitic tectonic coal is decreased.
3. The reflectence and hydrocarbon
content of tectonic coal is increased.
All of above facts suggest
that the physical and mechanical properties of tectonic coal was changed
by structural stress during the geological history. This kind of change
is called deformation metamorphism or dynamometamorphism of coal.
Our studies show that the zone
with tectonic coal will have a propensity for gas and coal outbursts and
spontaneous combustion. Geologists and mining engineers of China consider
tectonic coal as a useful indicator used for forecasting outburst zone
and dangerous zone of spontaneous combustion of coal
.
AAPG Search and Discovery Article #90939©1997 AAPG Eastern Section and TSOP, Lexington, Kentucky