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U.S. Department of Energy
Office of Scientific and Technical Information

Madisonville area-wide subsidence investigation. Final report

Technical Report ·
DOI:https://doi.org/10.2172/5672437· OSTI ID:5672437

An areawide subsidence investigation was conducted in Madisonville, Kentucky by U.S. Office of Surface Mining Reclamation and Enforcement to determine mechanisms of abandoned underground mine subsidence and to assess the potential for future subsidence. Information and data from geotechnical investigations, subsidence damage surveys, borehole camera inspection of conditions in abandoned mines, and previous subsidence investigations were analyzed. The analyses indicate that pillar crushing, and in some locations, roof collapse, in the flooded mines of the Number 11 Coal underlying Madisonville are the dominant causes of subsidence. The high extraction ratio (up to 80 percent) and undersized pillars particularly in panel sections of the mine, leaves insufficient support for the overburden weight. Surface sag subsidence 'troughs' develop as pillars progressively crush within worked-out mine panels. Larger pillars left in the Number 11 Coal mine entries, and in both entries and panels of some Number 9 Coal mines, apparently are competent enough to support the overburden at the present time although some subsidence of strata above the Number 9 mines has begun. Differential settlement at the surface is responsible for the extensive structural damage to buildings, and typically results where stronger entry, rib or barrier pillars provide support but are adjacent to collapsing panels. Soils problems may also be causing structural damage at some locations.

Research Organization:
Office of Surface Mining Reclamation and Enforcement, Pittsburgh, PA (USA). Eastern Technical Center
Sponsoring Organization:
U.S. Department of the Interior, Office of Surface Mining Reclamation & Enforcement
OSTI ID:
5672437
Report Number(s):
PB-91-164806/XAB; OSM--590
Country of Publication:
United States
Language:
English