Approximately 12 stream miles are polluted with abandoned mine drainage (AMD) from historic coal mining in the lower Kettle Creek watershed in northcentral PA. Remediation of these streams was a main focus of TU's Kettle Creek Home Rivers Initiative (1998-2006). Although the Home Rivers Initiative was closed in 2006, TU continues to take a lead role in restoration of the lower Kettle Creek watershed in partnership with the local Kettle Creek Watershed Association. TU's Kettle Creek AMD projects continue to serve as a model for its West Branch Susquehanna Restoration Initiative. A highlight of completed AMD projects is provided below.
TU partnered with the Department of Energy's National Energy Technology Lab in Pittsburgh, PA to conduct an airborne remote sensing survey of the abandoned mine drainage in lower Kettle Creek watershed. This study used thermal infrared and geophysical instruments to gather data on the location of abandoned mine drainage. The data were very helpful in determining where AMD collection was needed, where AMD source reduction efforts should be directed, and where further water quality and hyrdogeological assessment should be focused. Most importantly, follow-up hydrogeological studies in 2007 led to the finding that contaminated baseflow contributes 30-50 percent of the pollution loads to the Twomile Run watershed. As a result, reliance upon only conventional "collect and treat" methods of the point source discharges would not have led to successful stream recovery. As a result, reclamation has been adopted as a major component of the overall remediation strategy as it is the only way to effectively address the contaminated baseflow.
Four passive treatment systems were constructed in 2004 to treat AMD that pollutes the headwaters of Robbins Hollow, a tributary to Twomile Run. Vertical flow ponds, an anoxic limestone drain, and limestone upflow ponds remove iron and aluminum and add alkalinity to the East Branch and North Branch of the Robbins Hollow headwaters. The discharges that emanate downstream from this treatment system complex will be addressed by another passive treatment system, resulting in the completion of remediation for Robbins Hollow.
The objective of this project was to reclaim 57 acres of abandoned surface mine land and reduce the first major source of abandoned mine drainage that pollutes Twomile Run, which is a Class A native brook trout stream above the AMD pollution. The reclamation was accomplished through regrading, bio-capping with an organic soil substrate, and establishing permanent vegetative cover. The project has significantly reduced the infiltration of clean surface water runoff from reaching subsurface acid-forming materials, which reduced the formation of AMD from this site. Some flows of AMD continue from the site, which is to be expected, and these remaining flows will be treated by the Swamp Area Passive Treatment System.
In 2000, the Pennsylvania Department of Environmental Protection's Bureau of Abandoned Mine Reclamation built a passive treatment system to treat AMD that pollultes the Middle Branch, a tributary to Twomile Run. Though it initially worked well, there was a gradual decrease in treatment performance. This project investigated the cause of decreased performance and resulted in rehabilitation of the passive treatment system in 2007 to improve its performance and longevity. The highlight of this project is that due to the successful rehabilitation and treatment of the discharges, water quality now supports native brook trout and other aquatic life in the section of stream that has been lifeless for nearly 100 years.
The KC204 discharge from the No. 1 mine historically flowed through another nearby drain, KC204A, and through several entries that drain to Milligan Run, a tributary to the West Branch Susquehanna River that is polluted by AMD along its entire length. During the last 30 years, flow through KC204A and the Milligan Run mine entries has been blocked by subsidence, causing the mine pool to rise and discharge to Kettle Creek through KC204. Under high flow conditions the mine pool is estimated to contain approximately 38 million gallons of AMD. The failure of the KC204A blockage and the sudden release of the mine pool would be catastrophic for lower Kettle Creek and would impact the West Branch Susquehanna River. Completed in 2010, this project involved installing monitoring wells into the deep mine, excavating the collapsed Milligan Run entries, and installing five collection trenches (French drains) to facilitate free drainage for the purpose of reducing the potential for a mine blowout.
Director, Eastern Abandoned Mine Program
18 E. Main Street, Suite 3
Lock Haven, PA 17745
Email Amy Wolfe