AN ONGOING ASSESSMENT OF SCARLIFT 15 ABANDONED MINE DRAINAGE REMEDIATION SYSTEM, RANSHAW (NORTHUMBERLAND COUNTY) PA

The Scarlift 15 vertical flow remediation site was installed near Ranshaw, PA., in 2006 to treat AMD from the Corbin Mine Drift, a discharge with a pH of about 4 and high metals. The system was designed to raise pH and alkalinity and lower metal loading (specifically of iron, aluminum and manganese) before discharge into Shamokin Creek. Since 2008, students from Bloomsburg University’s Aqueous Geochemistry class have performed a periodic reevaluation of chemical parameters to monitor the effectiveness of the system. Samples collected on September 30, 2016 were analyzed for selected metals, cations, and anions. In the 2016 sampling, water exiting the outflow pipes (averaged) from the last vertical flow pond was higher in pH (6.8 vs. 4.7), higher in alkalinity (78 vs. 0.4 mg/L as CaCO₃), and lower in aluminum (.08 vs. 3.6 ppm), indicating the system was still operating as designed for those parameters, although not as effectively as in 2012 (6.6 vs. 4.5, 90 vs. 0 mg/L as CaCO₃ and .022 vs. 4.6 ppm for pH, alkalinity and aluminum, respectively) and far less effectively that when the system first opened. Manganese concentrations changed little throughout the system in both 2016 (3.4 to 3.1 ppm) and 2012 (3.2 to 3.1 ppm), which was markedly different from when the system first started operating (4.5 to 1.1 ppm). Past studies indicated effective removal of iron by the system (from 27 to 0.2 ppm in 2007 and from 24 to 9.5 ppm in 2012), but 2016 analyses indicate a problem with the part of the vertical flow system that discharges from one of the two final vertical flow pipes. Iron concentration of the outflow from one pipe was lower than that of the AMD entering the system (10 vs. 19 ppm), still not as effective as in 2012. However, the concentration of the outflow from the other pipe was almost double that of the AMD entering the system, indicating a serious issue with the portion of the vertical flow system treating the discharge exiting that pipe.