Anthracite Remediation Strategy with SRBC
A plan for the cleanup and reuse of mine impacted land and water in the Anthracite Region of Pennsylvania…
EPCAMR has been utilizing existing borehole water elevations, abandoned mine drainage (AMD) discharge surface elevations, historic mining maps, structural contour geology maps, and geologic cross section maps to recreate the mine pools and regional drainage patterns in the mines, that we’ve termed multi-colliery hydrologic units. Our focus area, up until 2011, had been on the Western Middle Anthracite and the Southern Coal Fields with the help of a PA DEP Growing Greener Grant.
EPCAMR partnered with the Pennsylvania Department of Environmental Protection (PADEP) Bureau of Abandoned Mine Reclamation, Dauphin County Conservation District (DCCD), PADEP Pottsville District Mining Office, PADEP Bureau of Deep Mine Safety, U.S. Geologic Survey (USGS), and the Office of Surface Mining, Pittsburgh, to work on developing these models more accurately and water storage potential or reservoir capacity in their current underground dynamic flow patterns since much of the active pumping of these areas from the 1950s have since ceased. These mine pools have had over 50 years to fill up in some instances and to flow into others, connecting one mine pool to another, and eventually connecting to a surface mine abandoned mine discharge.
EPCAMR has contracted with the USGS through the DCCD as a sponsor to develop a groundwater modeling budget for the Western Middle Coalfields. MODFLOW software was used by the USGS in the estimation of mine pool volumes for this field using EPCAMR’s digital GIS layers related to barrier pillars, mine pools, flow paths, tunnels, geobasins and faults. Structural contours of the Buck Mountain Vein, the lowest mineable coal seam in the Western Middle Coal Fields, were created using USGS Coal Investigation Series reports and maps. The creation of structural contours for the Southern Coal Fields posed a special problem due to the absence of structural contour maps for a majority of the field, the complex geology and overturned beds that rise along Sharp Mountain.
EPCAMR staff had been tinkering with a 3-D geologic modeling software called earthVision which allows us, for the first time, to see underneath the surface of the abandoned mine lands, create structural contours from geologic cross sections and visualize these complex underground flooded mine pools. EPCAMR attempted to create structural contours of the Buck Mountain Vein for the Southern Anthracite Coal Field, but there are software limitations that do not allow the software to interpret beds that dip, dive, plunge, and rise over ninety degrees. In the Fall of 2010, EPCAMR staff were trained in the use of earthVision 3-D modeling software. The specialized software has the ability to estimate remaining coal and mine pool volumes as well. The training was helpful in building a base of typical applied uses of the software and tricks to overcome some software limitations.
There are billions of gallons of mine water in the flooded abandoned underground mines in mine pools and in surface mine water filled pits. This has been known for more than 50 years. In the Western Middle Coal Field alone, there are 58 underground water pools containing 38 billion gallons of water. These calculations were made in the 1950s by Stephen Ash and others in a series of U.S. Bureau of Mines Reports when many of the collieries were still mining and actively pumping water. Present day totals are much greater, now that all the mines have filled up and are discharging, in the Western Middle and the Southern Coal Fields. These numbers are what EPCAMR is trying to update, given all of the new underground and groundwater modeling applications, structural geology modeling, and geographic information system (GIS) available to our partners on this project. Please see the Mine Pool Mapping Initiative page for an update.
March 11, 2010, EPCAMR and SRBC staff held a regional meeting at the Penn State Hazleton Campus to discuss the development of an Anthracite Region AMD Remediation Strategy for the Susquehanna River Basin and for EPCAMR to seek out additional mining maps and locations of other references, borehole, or discharge data that would assist us with covering the gaps that we have located throughout the entire four Anthracite Coal Fields. EPCAMR even put forth several proposals to further develop the mine pool mapping initiative in its Northern Bituminous Region to map out those areas to see if it can be duplicated state-wide in the future.
Future work is planned in partnership with the Susquehanna River Basin Commission (SRBC) and the Lackawanna River Corridor Association for the Lower Lackawanna River Watershed, particularly the Old Forge AMD Borehole and the Scranton-Metro Mine Pool complex in the Northern Anthracite Coal Fields. EPCAMR has secured funds from the SRBC to work in the Wyoming Valley, Upper Lackawanna (completing the Northern Anthracite Field) and some more detailed work in the Southern Anthracite coal field to pick up where we left off with Growing Greener Funding. A major portion of both of these coal fields lie in the Susquehanna River Basin. Additional funding has been secured to work in the Eastern Middle Anthracite Coal Fields as well.
The mine pools may be viewed as both a curse and a blessing in disguise. Extensive groundwater pollution and thousands of miles of streams degraded by AMD are the curse of more than 200 years of mining anthracite coal. Estimates show that it will take anywhere from 100 – 500 years for all the pyritic material to leach from a given mine and eventually produce water that meets water quality standards. The blessing in disguise is the potential availability of billions of gallons of water in the mine pools and high volume AMD discharges should be seen as a resource for present and future uses. The water and metal precipitates, such as iron oxide and aluminum oxide, have a realistic potential market once separated. A cost vs. benefit analysis can be run on individual mines to determine feasibility and possible profit potential for private sector investment. General framework concepts related to future economic redevelopment opportunities, mine pool re-use, underground storage potential, water withdrawal requests, AMD treatment, potential for frac water usage, hydroelectric potential, fisheries recovery, industrial use, and resource recovery of metals.
For example, due to complex synclinal folding of the Anthracite Region geology, mine pools are typically stratified similar to natural lakes. This hypothesis may be important when deciding how to manage the water resource side of things. Typically, the layers of water in the mine pools are referred to as “top water” and “bottom water”. The split is caused by shallow groundwater recharge, short circuiting within the mine and surface upflow discharges. Surface water enters the mine pool through subsidence features, fractures, faults, and other geologic surface features with openings to the mine pool. The bottom water is in a deep zone in the mine that is usually not well circulated. The bottom water typically has sulfate concentrations of several hundred milligrams per liter and relatively high concentrations of acidity and metals. Read more in a report titled Stratification in water quality in inundated anthracite mines, eastern Pennsylvania / by K.J. Ladwig.