Investigations into the role of groundwater in promoting floor heave in coal mine gateroads

Abstract

The geological environment of two South Wales collieries at which site investigations were carried out is summarised. This is followed by a review of identified geological parameters and their effects on floor heave under the headings of discontinuities, mineralogy, and groundwater. Methods of underground site investigation, laboratory testing, and data treatment are summarised. The effect of an increase of groundwater content on mechanical parameter values was quantified for laboratory tested rock cores, and in situ interbedded strata sections. The extent to which groundwater affects floor heave was found to be controlled by the mineralogical and structural nature of the floor strata.

Application of lithic and structural geological data to the assessment of ground stability above shallow abandoned coal mines

“…The lithologies in the borehole logs can be numerically quantified by assigning to each lithology a characteristic index number which also relates to the uniaxial compressive strength of the rock. Mineralogy, hence lithology, represented by the Mineralogical Index, Xi, has been shown to control mechanical behaviour of intact Coal Measures rocks (Hart 1986), where:…”