Use of mineralogical analysis in geotechnical assessment of rock strata for coal mining

The propensity of different rocks to ignite methane in underground mines by frictional effects has also been shown to depend on the mineralogy of the rock materials, whether determined by point counting of thin sections or by Rietveld-based XRD analysis. Abundant quartz, feldspar, and rock fragments in sandstones, for example, increase the likelihood of frictional ignitions, whereas clay minerals and (especially) carbonates in the rock reduce the frictional ignition potential. Pyrite in the rocks, if present, also increases the ignition risk; pyrite undergoes exothermic oxidation at high temperatures whereas other minerals respond by simple heating due to rock-on-rock or pick-on-rock friction processes.