A SEDIMENTOLOGICAL ASSESSMENT OF THE EFFECTIVENESS OF THE PINE FOREST ACID MINE DRAINAGE TREATMENT SYSTEM, ST. CLAIR, SCHUYLKILL COUNTY, PA

Discharge from the Pine Forest mine flows directly into the acid mine drainage (AMD) treatment system, which consists of an anoxic limestone drain (ALD) and four consecutive settling ponds. The key to an ALDs efficacy is that it remains anoxic to prevent the oxidation and precipitation of dissolved metals from armoring the limestone. The Pine Forest system, however, is not so anoxic due to a leak in the ALD. This leak causes the system to periodically plug up and requires that the drain be flushed.

To determine the repercussions, if any, to the system from this oxygen leak sediment samples were taken at the system outflow, in each settling pond, at the ALD outflow, and at the mine outflow. Samples were dried and analyzed with XRF to determine elemental and mineralogical composition and viewed under a SEM to determine biological composition. Results from the XRF analysis suggest that the system is effectively removing heavy metals and sulfate as it was designed to, but with significant amounts of metal precipitates right at the ALD outflow. SEM results show an abundance of iron flocculate and the bacteria Gallionella with concentrations highest near the ALD outflow suggesting that the bacteria and its precipitate may be responsible for the periodic clogging of the system.