WATERSHED RESTORATION

Acid (or abandoned) mine drainage (AMD) is a pollutant formed through a chemical reaction between sulfide minerals, found within mines, and oxygen and water. When combined, sulfuric acid and dissolved iron result. Moreover, it isn’t a one-time event: the acid is a corrosive agent, continuously dissolving more rock and releasing additional metals and minerals. As long as the raw materials remain exposed, AMD production will continue.

AMD is prevalent on abandoned mine lands. In Pennsylvania alone, nearly 5,000 miles of waterways are affected. The first problem? Unreclaimed land. Whenever rain or snowmelt encounter mining waste, AMD production begins. Runoff then leaves the site, either seeping into the underground water table or traveling to nearby streams.

Second, when the mines were active, large pumps removed groundwater from the mines. As the industry declined, however, they went offline. Over time the subterranean shafts and tunnels were filled and vast underground pools were formed. Additional precipitation continued to increase water levels. Immense water pressure was the result. In some cases, this resulted in natural seeps or drainage areas. In other cases, basements of businesses and homes flooded. To counter the pressure, boreholes – vertical escape routes for the trapped water – were drilled. Unfortunately, while the pressure was relieved, the untreated water was discharged back into nearby streams, perpetuating the cycle of contamination.

Regardless the source, AMD produces contaminants that far exceed an ecosystem’s natural processing ability. The discharged metals drop out suspension, blanketing streambeds and banks with an orange/yellow-orange sludge. A potent sulfuric smell, similar to rotten eggs, also hangs in the air.

AMD makes affected waters more than impotable. It impacts the entire ecology of an area. Elevated metal concentrations and lower pH levels make water quality inhospitable to an array of plants and animal life. The orange sludge, moreover, smothers essential habitat, robbing the streambed and lower banks of their roles as sources of food, shelter, and nesting grounds. AMD also disrupts photosynthesis in plants and clogs the gills of aquatic organisms, hindering their ability to breathe. The decline of the smallest creatures triggers a domino effect that ripples up the food chain. Potentially, the stream is rendered biologically dead.

EC prioritizes mitigating the impact of AMD in our local watersheds. Our work involves a two-pronged approach: treatment and prevention. Treatment of AMD can be done passively, where natural processes allow iron to settle out of the water, which is exemplified by the Espy Run Constructed Wetlands site. Treatment can also be done actively, using mechanical aeration and/or chemical additives. EC’s Askam Borehole AMD Treatment system utilizes the former: a Maelstrom Oxidizer injects massive amounts of oxygen into the water, accelerating iron precipitation. The iron then collects in a settling pond versus continuing downstream.

However, the ideal solution is to stop AMD at its source. EC achieves this through reclamation and stream reconstruction. We actively revitalize damaged and destroyed stream channels through reconstruction, channel lining, and revegetation. This keeps water on the surface, instead of seeping underground and coming into contact with sulfide-rich materials that generate AMD. Moreover, this reduces the volume of water requiring treatment downstream at EC’s facilities.

In both cases, EC uses its restoration projects to educate the public about lingering problems. Often, communities have accepted orange waterways as the norm, either ignoring them or believing little can be done. Part of EC’s mission is to increase awareness about the damage abandoned mine lands do to the region, as well as the solutions that do exist. Many other agencies, organizations, and private individuals are working to reduce the effects of AMD. If you want to learn more, visit the Partners & Links page to discover others dedicated to this goal.