Geomicrobiological and mineralogical characteristics and strategies for remediation of abandoned mine drainage at the Oak Hill boreholes
Advisor: Selby Cull
A pressing problem affecting the Schuylkill watershed in Western Pennsylvania is runoff from abandoned mines, which can include metals such as iron, manganese, copper, arsenic, and zinc. These dissolved metals migrate from mining sites to local ground and surface water, causing contamination of drinking water and damage to local ecology. Metals easily enter solution in areas of low pH, but the contamination of neutral sites has led to increasing interest in this typecircumneutral of drainage.
The United States Geological Survey (USGS) monitors a circumneutral AMD site called the Oak Hill Boreholes, which discharges 2,830 gal/min of water with high concentrations of Fe and Mn into the West Branch Schuylkill River. After seven years of data collection from this site and others, the USGS is now studying whether the Oak Hill boreholes could be treated with aerobic ponds and iron oxide sludge removal. One objective of this study is to understand the microbial and mineralogical characteristics of iron oxide sludge found at the site to better understand how its removal will influence water downstream. I will identify the mineralogical composition of iron oxide samples taken from the Oak Hill boreholes field site by comparing their reflectance to USGS standard reference samples using a spectrophotometer. Light microscopy will be used to I will identify the presence of iron- and sulfur-oxidizing bacteria within the sludge using light microscopy and and will help determineresearch how these bacteria exacerbate mine drainage. With Lehigh University and USGS, I will participate inThis study will also involve field aeration experiments to test the effect of aeration on the boreholes site by examining the relationship between Fe and O2 concentrations, pH, alkalinity, degassing rates, and water temperatures and iron dissipation. If the combination of aeration and sludge removal successfully attenuates iron concentrations and reduces bacterial activity, future work will focus on implementing an efficient and cost-effective remediation design for this and other sites.