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Microseismic monitoring of a longwall coal mine. Volume II. Determination of seismic velocity.
Hardy-HR Jr.; Beck-LA
NTIS: PB/80-163405 :1-232
Volume II of this three-volume report describes the evaluation of a number of different field techniques and the seismic velocity data obtained at the Greenwich Colleries, Barnesboro, Pennsylvania, mine site where microseismic studies were carried out. Three methods were employed to evaluate seismic velocities; namely, surface refraction, downhole, and transmission. In all cases the seismic sources were either located on surface (mechanical impact) or near-surface (explosive charges). It was found that a mechanical source could be conveniently utilized to determine shallow velocities and make bedrock-regolith interface depth determinations. For deeper velocity determinations suitable explosive charge sources were required. In general, refraction data did not always plot in a linear manner and some subjective interpretation was necessary. The downhole method was useful for incremental vertical evaluation; however, the transmission method provided the most consistent average vertical velocity data.
CP; Final Contract Report
NTIS Accession No.
Pennsylvania State University
Page last reviewed: March 11, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division