Geotechnical assessment of skin reinforcement in underground mines

Current advances in roof support automation require a fast and effective skin reinforcement of underground mine roadways. To satisfy these needs a strong and tough fibre reinforced polymeric alternative is emerging as a logical substitute to the old steel mesh support system. Differences between steel mesh and polymer skin behaviour are investigated. Computational models are utilised to compare these two skin support systems with a view to optimising the performance needed for effective roadway skin reinforcement. In particular, development of a strong and resistant shell that minimises movement along the fractured rock and coal surfaces found between the roof bolt anchors is recommended. A strong surface adhesion and the strength of a reinforced polymer skin can provide the necessary toughening mechanism required to enhance roadway surface support by forming a reinforced polymer/rock surface layer. The fractured rock mass in its undisturbed phase is relatively stiff while confinement stresses exist. However, any dilation that occurs due to displacement along the rough surfaces of the fractured rock causes strata softening, bulking and movement into the mine opening. The polymer skin can provide active resistance to any movement along the fractured rock surface as soon as any movement begins to occur. Even partial de-bonding of the polymer from the rock surface may not significantly disturb this mechanism.