Abstract
The purpose of this paper is to provide background information and an update of hydrologic information regarding the Meigs Mine pool complex. Mine pool development, water quality, water quantity, and impacts to the local hydrology are briefly covered.
The mine complex is below drainage with the exception of the western edge of the Raccoon mine where the coal seam is just at or near Raccoon Creek, in SE Ohio. The overburden thickness ranges from 200 to 600 feet. Currently (December 2007), the mine pools are not being pumped, therefore an opportunity exists to study the flooding rates for these mines.
Near surface aquifers are impacted by surface tension induced fractures. In areas of low cover the inflow of groundwater to the mine are direct. In most cases, the stream loss may be going into the shallow subsurface, facilitated by fracture dilation. If the strata are friable, the ability of the fractures to heal is diminished as is the case in some streambed dewatering above the Meigs 2 mine. Documented stream loss has occurred in several tributaries.
Recharge into the mines exhibits a seasonal variability. Incremental differences in the fill rates are apparent from specific monitoring points. In general, the pool rises and falls in concert over the complex. Recharge rates were volumetrically determined for the mine pool complexes.
Since there is a potential for uncontrolled discharges to low-lying stream valleys, maintaining a lower pool elevation through pumping is required. Water quality will improve dramatically with time. Due to the partially unflooded mine pool, the mine pool water quality may require perpetual treatment.
Key Words: mine pool, Meigs Mine, longwall mining, stream dewatering, flushing