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Application of photogrammetric techniques in assessing underground mine opening deformations and stability.
Eichfeld-W; Ono-E; Chugh-YP; Chen-G
Rock Mechanics: Contributions and Challenges: Proceedings of the 31st U.S. Symposium, June 18-20, 1990, Colorado School of Mines, Golden, Colorado. Hustrulid WA, Johnson GA, eds., Brookfield, VT: A.A. Balkema, 1990 Jan; :587-594
Underground mine workings and the associated surface deformations are studied for many Reasons. Among these reasons are the determination and improvement of mine stability characteristics and the prediction and mitigation of surface subsidence effects. Research now indicates that the characteristics of underground roof-pillar-floor interaction and particularly the strength of the floor have significant impact on the behavior of the mine workings. Data which describes the deformations of the roof, pillars, and floor independently as well as in combination is difficult to obtain using common measurement techniques but is required to properly account for the floor behavior. The work described here is an effort to efficiently and economically measure the elements of roof-pillar-floor interaction independently. Roof-pillar-floor interaction may manifest itself underground as pillar settlements, floor heave, squeeze, cutter-roof failure, pillar sloughing and/or coal mine bumps. Measurements and observations of these phenomena and associated engineering properties are made with various load cells, borehole measurement devices, and surveying equipment, including very accurate tape extensometers. The primary equipment used to measure the movements in an entry is the tape extensometer and the primary movement that is measured is the relative convergence. While very accurate determinations of convergence are obtainable, the use of the tape is subject to the limitations of surveying equipment which are discussed later and the measurement of convergence does not describe entry deformation adequately for making mine stability studies. The use of photogrammetric techniques to improve the measurement of entry deformations is the focus of this study. The use of land surveying equipment underground is difficult, time consuming, and labor intensive. The equipment has the potential to be extremely accurate but this potential may not be realized underground for several reasons. First of all, fixed points of reference are difficult to establish and maintain at frequent intervals in the mine environment. Such points need to be close to the sites where roof-pillar-floor interaction is to be monitored in order to be useful. More significantly, land surveying procedures (including the use of a tape extensometer) require a series of individual observations. The time which passes during the measurement process is time during which the roof-pillar-floor interaction is proceeding and the first observation may not capture the same situation as the last. The development of a photogrammetric measurement technique will eliminate these problems.
Rock-mechanics; Engineering; Mining-industry; Surface-properties; Ground-control; Ground-stability; Structural-analysis; Underground-mining; Monitoring-systems; Measurement-equipment; Photographic-equipment; Floors; Coal-mining; Equipment-reliability; Mining-equipment
Rock Mechanics: Contributions and Challenges: Proceedings of the 31st U.S. Symposium, June 18-20, 1990, Colorado School of Mines, Golden, Colorado
Southern Illinois University, Carbondale, Illinois