LAUSR

Mine excavation rate is a fundamental parameter that controls production and efficiency in underground mines. The length of each cycle excavation (LCE) is vital to decrease the cycle numbers and improve the excavation rate. This paper presents a new approach to determine the LCE for the excavation of roadways in coal mines. Initially, a roof stability model of roadway is established using finite difference method (FDM) to obtain the relationship between principal stresses in the roof of the excavation and the LCE. Finally, specific geological conditions are taken into consideration to determine the better suited LCE for a given roadway. The latter assumes a simple beam-problem, in which a beam fixed at two ends and subjected to uniformly distributed loads. The proposed approach thus combines mining stress and geological conditions to provide an indication of an optimal LCE for the roadways under consideration. The results show a safe increase in excavation rate could be achieved by implementing an LCE based on a 6 m advance with temporary support, followed by the installation of the permanent support using rock bolts installed at 0.8 m spacing.