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Tailgate stability within longwall coal mining is critical to longwall productivity and safety of mine personnel. A mechanistic model was developed and tested to explain observed high deformation tailgate behaviour characterised by lateral strata movement. Field investigations were conducted at three Australian longwall mines with an emphasis on the measurement of; horizontal strata movement about gateroads during longwall extraction, and the load/deformation characteristics of standing supports. 3D numerical modelling was used to simulate tailgate deformation, and interaction of various support types and design strategies. The sensitivity of strata and support behaviour to; variations in roof geology, strength of sliding interfaces, depth of cover, pre-mining horizontal stress magnitude and orientation, and strength and stiffness characteristics of standing supports was modelled. Laboratory investigations of a standing support product, the ???Can???, at reduced scale (one third) were conducted. The tests determined the loading mechanics of the product and provided a basis for optimisation of the engineering properties (strength and stiffness). Horizontal strata movement about longwall extraction was found to have a significant impact on strata behaviour at two of the three mines investigated. The term ???skew roof??? was coined to describe the deformation process. Essentially the roof strata was found to ???skew??? towards the approaching goaf. The key geotechnical factors found to control the skew roof mechanism were; magnitude and orientation of the pre-mining horizontal stress, presence of weak interfaces along which sliding could occur, and shear strength of the interfaces. Measurement of the nature and extent of skew roof deformation specific to each mine provided a sound engineering basis for support design. These included; the relative roles of long tendons versus standing support, optimal pattern (position across and along the roadway) of standing supports, and appropriate strength and stiffness characteristics. The findings were successfully implemented at Metropolitan Colliery in particular, where adequate tailgate serviceability has been achieved within a high deformation environment, and whilst maintaining a relatively small chain pillar width. The research has achieved an alternative to empirical and trial and error tailgate support design methods.

Thesis (M.S.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xiii, 82 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 65-66).

Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xiii, 379 p. : ill. (some col.), maps (some col.). Vita. Includes abstract. Includes bibliographical references.

Thesis (B.S.)--University of Alaska, 1940. / Alaska "Territorial Department of Mines reports" or "TDM reports" are a collection of reports, notes and maps written by Dept. employees working out of several field offices throughout the territory. Series titles and numbers within the collection were retrospectively assigned with the exception of the few written after statehood (1959). Report contains information on the Yukon River Mining Region, Circle Quadrangle. Includes bibliographical references (leaf 80). Also available in electronic format via Internet.

Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1930. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed February 10, 2010) Includes bibliographical references (p. 63-64).

Thesis (Ph. D.)--University of Pennsylvvania, 1933. / Published also without thesis note. eContent provider-neutral record in process. Description based on print version record. "Seleted bibliography": p. 213-218.

Thesis (M.A.)--University of Alberta, 1963. / Includes bibliographical references (p. [135]-149).

Thesis (Ph. D. (Economics))--University of Pretoria, 2003. / Includes bibliographical references (leaves 174-181).

Thesis (M.A.)--Ohio State University, 1915. / Available online via OhioLINK's ETD Center.