Characterisation of roof behaviour and primary support response at Ulan West Mine

This paper outlines a study of roof behaviour at Ulan West Mine which addressed factors such as the influence of mining direction and sequence on roadway stability; stress impacts during intersection formation; variation in strata conditions, choice and timing of support installation in relation to strata management triggers. Three-dimensional modelling of itersection formation was undertaken that included quantifying the impact of grouting cables for different roof types. This was augmented with 2D modelling to investigate immediate roof beam performance, particularly in relation to heights of softening and potential strata response. Further analysis was then undertaken using an analytical beam-column model to assess the bending behaviour of the roof and its relationship between roof convergence and support load. Several cases were examined for both Type A and Type B roof where the coal roof beam remains intact or is subjected to stress related damage. The mechanisms at play during roadway development at Ulan West involve interaction between the immediate coal roof beam, the ability of the overlying strata to carry load and the mining induced stresses imposed on these units. The combined analysis allowed an update of the Trigger Action Response Plan (TARP).