Statistical analysis of subsidence type and delays over room and pillar coal mines

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1985

OSTI ID:5951236

Van Besien, A C

Most underground coal mines in the US, both now and in the past, use room and pillar mining methods. The onset of subsidence over abandoned room and pillar mines may be delayed for many years after mining and has been considered difficult, if not impossible, to predict. The objective of this research was to develop empirical methods of predicting the onset of subsidence. Site-specific mining and geologic data were collected on 80 subsidence events. Statistical analysis of this data indicated that subsidence characteristics are strongly influenced by the competence of materials in the lower half of the overburden. The type of subsidence, whether it will be of pit or sag type, is determined by seam depth, the percentage of unconsolidated material (soil) in the overburden, and the percentage of competent material (mainly limestone and sandstone) in the lower half of the overburden. For sag subsidence, the delay between mining and subsidence is influenced primarily by pillar stress and by the competence of material in the lower half of the overburden. Maximum sag subsidence delays, for a given pillar stress, are associated with those sites having 20%, or less, competent strata in the bottom half of the overburden. Considerable variation is found in those sites having more than 20% competent materials in the lower half of the overburden.

• Research Organization: Missouri Univ., Rolla (USA)
• OSTI ID: 5951236
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010900* -- Coal
Lignite
& Peat-- Environmental Aspects
012000 -- Coal
Lignite
& Peat-- Mining
ABANDONED SITES
CLASSIFICATION
COAL DEPOSITS
COAL SEAMS
DEPTH
DIMENSIONS
FORECASTING
GEOLOGIC DEPOSITS
GROUND SUBSIDENCE
MATHEMATICS
MECHANICS
MINERAL RESOURCES
MINING
OVERBURDEN
RESOURCES
ROOM AND PILLAR MINING
SOIL MECHANICS
STATISTICS
TIME DEPENDENCE
UNDERGROUND MINING