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Investigation of problems and benefits of underground multiple seam coal mining.
Washington, DC: U.S. Department of Energy, Mining Research and Development, Contract C-14242P, 1981 Oct; :1-292
It is estimated that over 156 billion tons of coal in the United States are amenable to multiple-seam mining. However, currently most operations mine only a single seam, and in the past indiscriminate practices have sterilized large amounts of coal in contiguous seams. In the interests of conservation, it is imperative that procedures be followed that enhance resource recovery. The total life-cycle costs of mining are site specific because of the wide variations in land acquisition costs, capital expenditures, resource recovery, labor productivity, and geological conditions. However, under similar circumstances the costs of single- and multiple-seam mining are within 5 percent, using the best available technology. Improvements in present methods could lower costs of multiple-seam mining further, making it more competitive. Ground control (entailing roof support, bumps, and subsidence) is the most important technical problem encountered in multiple-seam mining, mainly caused by remnant pillars. However, the nature and thickness of partings and overburden, as well as the type of floor, roof, and coal play a significant role. Ventilation control to prevent air leakage and gas accumulation, haulage difficulties because of floor undulations and roof falls, and fear of water inundation from an abandoned upper seam are other problems to be considered. Spontaneous heating may be experienced in some western coals. Changes in regulations that streamline permitting procedures and encourage multiple-seam mining need to be introduced. Union attitudes that permit better coordination between seams should be fostered. A research program addressing some of these problems is presented.
Underground mining; Coal mining; Strata control; Rock bursts; Ground subsidence; Roofs; Supports; Support pillars; Ventilation; Mine haulage; Spontaneous combustion; Research programs; ERDA/012000
CP; Final Contract Report
NTIS Accession No.
Washington, DC: U.S. Department of Energy, Mining Research and Development, Contract C-14242P
IL; DC; PA
Engineers International, Inc.
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division