skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Investigation of subsidence event over multiple seam mining area

Abstract

An investigation was performed to determine the sequence of events which caused the 1987 surface subsidence and related damage to several homes in Walker County, Alabama, USA. Surface affects compared to mine maps indicated the subsidence to be mine related. However, two coal seams had been worked under this area. The upper seam, the American seam, ranged from 250 to 280 feet beneath the surface in the area in question. It was mined-out before 1955 by room-and-pillar method leaving in place narrow-long pillars to support the overburden strata, and abandoned in 1955. The lower seam, the Mary Lee seam, ranged from 650 to 700 feet beneath the surface. The Mary Lee seam had been abandoned in 1966 and subsequently became flooded. The dewatering of the Mary Lee seam workings in 1985 caused the submerged pillars to be exposed to the atmosphere. Due to multiple seam mining and the fact that workings had been inundated then dewatered, a subsurface investigation ensued to determine the sequence and ultimate cause of surface subsidence. Core sample tests with fracture analysis in conjunction with down-the-hole TV camera inspections provided necessary information to determine that the subsidence started in the lower seam and progressed through themore » upper coal seam to the surface. Evidence from the investigation program established that dewatering of the lower seam workings caused the marginally stable support pillars and the roof to collapse. This failure triggered additional subsidence in the upper seam which broadened the area of influence at the surface.« less

Authors:
Publication Date:
Research Org.:
Office of Surface Mining Reclamation and Enforcement, Pittsburgh, PA (US)
OSTI Identifier:
20026832
Resource Type:
Conference
Resource Relation:
Conference: 16th annual national meeting of the American Society for Surface Mining and Reclamation, Scottsdale, AZ (US), 08/13/1999--08/19/1999; Other Information: PBD: [1999]; Related Information: In: Mining and reclamation for the next millennium. Proceedings of the 16th annual national meeting of the American Society for Surface Mining and Reclamation, by Bengson, S.A.; Bland, D.M. [eds.], 745 pages.
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; ALABAMA; COAL MINING; ROOM AND PILLAR MINING; ABANDONED SHAFTS; GROUND SUBSIDENCE; WATER REMOVAL; FAILURE MODE ANALYSIS

Citation Formats

Kohli, K.K. Investigation of subsidence event over multiple seam mining area. United States: N. p., 1999. Web.
Kohli, K.K. Investigation of subsidence event over multiple seam mining area. United States.
Kohli, K.K. Thu . "Investigation of subsidence event over multiple seam mining area". United States. doi:.
@article{osti_20026832,
title = {Investigation of subsidence event over multiple seam mining area},
author = {Kohli, K.K.},
abstractNote = {An investigation was performed to determine the sequence of events which caused the 1987 surface subsidence and related damage to several homes in Walker County, Alabama, USA. Surface affects compared to mine maps indicated the subsidence to be mine related. However, two coal seams had been worked under this area. The upper seam, the American seam, ranged from 250 to 280 feet beneath the surface in the area in question. It was mined-out before 1955 by room-and-pillar method leaving in place narrow-long pillars to support the overburden strata, and abandoned in 1955. The lower seam, the Mary Lee seam, ranged from 650 to 700 feet beneath the surface. The Mary Lee seam had been abandoned in 1966 and subsequently became flooded. The dewatering of the Mary Lee seam workings in 1985 caused the submerged pillars to be exposed to the atmosphere. Due to multiple seam mining and the fact that workings had been inundated then dewatered, a subsurface investigation ensued to determine the sequence and ultimate cause of surface subsidence. Core sample tests with fracture analysis in conjunction with down-the-hole TV camera inspections provided necessary information to determine that the subsidence started in the lower seam and progressed through the upper coal seam to the surface. Evidence from the investigation program established that dewatering of the lower seam workings caused the marginally stable support pillars and the roof to collapse. This failure triggered additional subsidence in the upper seam which broadened the area of influence at the surface.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jul 01 00:00:00 EDT 1999},
month = {Thu Jul 01 00:00:00 EDT 1999}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share: