Design Optimization in Underground Coal Systems. Sections 1--4. Interim Report, January--March 1979: Fid-Bau Portal

Design Optimization in Underground Coal Systems. Sections 1--4. Interim Report, January--March 1979

C. Haycocks

Work continued on the longwall simulator with a more detailed examination of the potential for utilizing a roof characterization factor in the estimation of roof stability, both in the development entires as well as above the support line at the face. The proposed roof characterization factor, which is tentatively being incorporated at this time, is similar in general concept to that advanced by Terzaghi, 1946; Barton, 1974; and Bieniawski, 1976. The primary factors currently being utilized are strata thickness, moduli and interlayer relationships, joint densities, continuities, surface characteristics and orientations, and strata strengths. The development of such an approach using a roof-characterization factor for laminated rocks has encountered some special problems, particularly that related to inter-strata loading in the immediate roof. This loading is a factor in roof stability in addition to joint density and rock properties. Currently an arbritary method of deciding which layers will load the underlying strata is being based upon the work developed using elastic analysis by Obert, Duvall and Merrill, 1960. The benefits of the roof characterization approach are a much more realistic evaluation of roof conditions, and therefore, a more accurate prediction of strata responses during underground mining. Work continued on the final report of the roof truss portion of the work. The report includes the theory, modeling method, experimental and field data, and the analysis and correlation of the above, in addition to recommendations concerning efficient installation and usage of roof trusses. The development and maintenance of computer programs used in the work are also discussed in detail. (ERA citation 04:051076)