Subsidence and water intrusion for shallow longwall mine planning in the Illinois coal basin: A case study

Conference · Fri Dec 31 04:00:00 EST 1993

OSTI ID:143752

Kendorski, F S ^[1]

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1. Morgan Mining & Environmental Consultants, Ltd., Downers Grove, IL (United States)

A coal property in southern Illinois is being studied as a shallow longwall coal mine at depths averaging 250 ft and as shallow as 180 ft. The shallowness results in a super-critical panel width (depth much less than width) with 850-ft panels. The fractures associated with full-extraction coal mining wall likely reach the surface and act as pathways for water migration. The shallow subsidence phenomena result in a more gentle lowering of overlying strata in large blocks with ``tearing`` at the margins of the panels developing continuous potential water pathways. Strain zone predictions indicate fracturing of strata from the mining horizon to the surface. Bed separations caused by subsidence in the strata and below a sandstone aquifer could result in ponding of waters that could be suddenly released into the mine at rates several times the normal steady-state inflow. Timing mining under streams for dry seasons will also minimize water intrusion potentials. Silting-up of pathways and resettlement of strata will eventually reduce water flows in an area. Recognizing areas of mining with panel edges intersecting water sources and pathways can allow pre-planning for water handling.

• OSTI ID: 143752
• Report Number(s): CONF-930646--
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
GEOLOGIC FRACTURES
GEOMORPHOLOGY
GROUND SUBSIDENCE
HYDROLOGY
ILLINOIS
LONGWALL MINING
MITIGATION
STRATA CONTROL
STRATIGRAPHY
WATER INFLUX