Performance of polymer skin spray-on liner in coal mines
Current developments in roof bolting automation requires fast and effective skin support of underground coal mine roadways.Astrong and tough fibre reinforced polymeric thin spray-on liner (TSL) is emerging as a logical substitute for the old steel mesh support system. This paper investigates the effectiveness of a reinforced polymer skin liner in coal mines subject to high horizontal stress. Typically, high lateral stresses induce low angle shear fractures within the roof strata inducing roof convergence and degradation of the roof strata in mine roadways. Fully encapsulated steel bolts provide effective confinement to fractured strata while the strata skin between the bolts remains largely unconfined and prone to failure. Investigations using numerical modelling and laboratory experiments suggest that a polymer basedTSL can outperformsteel mesh and significantly improve stability of the strata skin between the bolts. Strength tests performed on 5mm thick polymer sheets of indicate load bearing capacities comparable to the heavy duty steel mesh currently used as a skin support underground. Puncture tests and polymer adhesion to the substrata indicate that the polymer TSL can provide additional benefits to the skin support.