Uniaxial compressive strength (UCS) is the most fundamental physic-mechanical parameter that is primarily required in any geotechnical and geological engineering projects. The dependence of strength of primary rocks on the alteration indices have been previously studied, but it is unknown for secondary/ sedimentary rocks. Therefore, in this paper, Lower Gondwana coal measure rocks (sandstone and shale) have been studied geochemically and geomechanically. The provenance, paleodepositional environment, tectonic setting, palaeoclimate, and UCS of the Barakar and Raniganj coal measure rocks have been assessed. The study revealed that an arid, non-marine and deltaic depositional environment prevailed during the sedimentation of Barakar and Raniganj Formations. The provenance was deduced to be mafic igneous. It was also deduced that the Lower Gondwana sandstone is clay rich, and the sandstone and shale cannot be classified using the chemical classification scheme for terrigenous clastic sediments. The dependence of UCS on the weathering indices have been evaluated and a positive relationship was obtained.
Keywords: Geochemical; geomechanical; coal measure rocks; weathering indices; Lower Gondwana