Abstract
The stability of roofs and floors in bord areas in coal mines is affected by a number of properties of the strata above and below the coal seam that is worked. These include the lithological character of the rocks, the sedimentary features contained within them, the geomechanical properties of the rocks, notably their strength and deformation moduli, the durability of the rocks on exposure, and the incidence and geometry of discontinuities. Accordingly, core material was obtained from a mine in the Eastern Transvaal Coalfield in order to investigate the influence of certain of these properties on the stability of the roof and floor of the mine. The investigation showed the existence of a number of sedimentary facies that had different geological characteristics and geomechanical properties. A large number of compressive and tensile strength tests were carried out on the core material, and the geodurability of the rocks of the argillaceous facies was also determined. The geodurability is assessed in terms of the free swell coefficient and the uniaxial compressive strength. It indicated that some of the argillaceous material was of very poor quality. The geodurability and tensile strength would appear to provide indications of the potential behaviour of the roof rocks as mining occurs and the uniaxial compressive strength helps in the understanding of failure of floors in coal mines. In particular, poor roof and floor conditions were found to be associated with rocks of the argillaceous facies. The most stable strata were the fine-grained arenaceous facies whilst those of the coarse-grained facies were somewhat less stable. The triaxial compressive strength and deformation moduli of some of the sandstones also were determined.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call