Summary
A typical roof profile for mine openings in the Great Northern Seam consists of a thin coal layer and several metres of claystone. From field evidence and shear flow analysis, the anchorage of fully grouted roof bolts in the claystone may fail. If so, the claystone may act as an extra load on the coal beam. Using voussoir beam theory, the relation between the minimum thickness of the coal beam, the thickness of the failed claystone and the width of the entry has been determined. The analysis is satisfactory for field performance observed in a number of case studies. Proposals are made on possible improvements to mining techniques.
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Seedsman, R. Back-analysis of roof conditions in the Great Northern Seam, Newcastle Coal Measures, Australia, using voussoir beam theory. International Journal of Mining and Geological Engineering 5, 15–27 (1987). https://doi.org/10.1007/BF01553530
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DOI: https://doi.org/10.1007/BF01553530