Autonomous Thin Spray-On Liner Application in Irregular Tunnel and Mine Roadway Surfaces

Abstract

An autonomous spray application system for a structural Thin Spray-on Liner (TSL) is targeting productivity and safety on underground coal continuous miners by potentially replacing steel mesh, and has broader applications as surface support and confinement in metalliferous mines and civil tunnelling. Polymer chemistry, coating formulation, geotechnical assessment and the autonomous application system are being developed as an integrated package as part of a continuous miner automation project. This polymer-based TSL system has significant benefits over conventional steel mesh skin confinement, including being more automatable by spray application, providing complete skin confinement and active skin reinforcement as a fast-curing composite with substrate, and having effective fire retardant properties for the polymer and the underlying coal. This paper presents a preliminary assessment of distance sensing systems that would enable autonomous adaptation of a nominal spray path to spray a consistent thickness of TSL (nominally 5mm) over an irregular topography. Two alternate sensors are assessed; firstly, a 2D LIDAR mounted on a linear axis is used to produce a 3D surface profile for generating an adapted spray path; and secondly, a robot end-effector-mounted ultrasonic sensor is assessed for wall following techniques to dynamically adapt a nominal spray path.

Influence of Polypropylene Fiber on Tensile Property of a Cement-Polymer Based Thin Spray-On Liner

“…The findings validated that TSLs and variant layer combinations may be as effective or superior to conventional support materials for mitigating rockburst or similar damage in highly stressed mine environments. Due to its benefits, TSL has attracted increasing attention as an alternative to steel mesh in underground roadway support [12][13][14][15]. These liners may be used in hard rock mines and coal mines [2,[16][17][18].…”