A Look at Acid Mine Drainage in Montour Run
What we're doing about this top pollutant
Pittsburgh’s Coal Mining HistoryPennsylvania has a rich history rooted in the coal mining industry. Used to fuel the steel and iron industries, coal mining began in Pennsylvania in the mid-1700s. Bituminous (soft) coal was first mined in Pittsburgh about 1760 at "Coal Hill" (present day Mount Washington).
This coal mining heritage did not come without cost, though. For the first 200 years, it was mined without formal regulation and little thought of environmental consequences. Following the extraction of all the available coal from one site, operators would move to another mine site and leave the original mine abandoned, failing to remediate the environmental impacts caused by mining. In Pennsylvania, conservation districts, watershed groups and others have taken a lead role in cleaning up these abandoned mine sites with assistance from federal and state agencies.
Map from DCNR showing the bituminous coal fields across western Pennsylvania.
Abandoned Mines in Montour RunThe legacy of coal extraction efforts, both via surface mines and deep mines, has significantly impacted the Montour Run Watershed. Much of the watershed is listed as impaired for pH and metals from abandoned mine drainage (AMD). In 2003, the Montour Run Watershed Association engaged BioMost, Inc. to investigate abandoned mine discharges in the watershed.
In the report 13 discharges were evaluated and prioritized for treatment. All identified discharges were located in the headwaters of the North and South Forks except one at the headwaters of Milk Run. Since that initial report, substantial progress has been made on AMD in the Montour Run Watershed. Five of the top six priorities identified have been treated with passive treatment systems. Most recently ACCD and several partners constructed the Milk Run System which was completed in 2019. These systems, along with changes in Pittsburgh International Airport’s de-icing protocols have resulted in Montour Run being stocked with trout by PA Fish & Boat Commission.
Abandoned mine discharge in the Montour Run Watershed showing iron in the water and coating the stream bottom. From here, this discharge enters a treatment system installed by the Montour Run Watershed Association.
Early assessments, such as the AMD Cleanup Plan, provided the groundwork for the recently completed Montour Run Watershed Assessment and Implementation Plan. This assessment seeks to continue making water quality improvements by examining the watershed today, identifying additional pollutant sources such as nutrients and sediment, and defining mitigation strategies to address these contaminants. These efforts will help us to better understand the existing resources of the watershed, those processes that have impacted it negatively in the past and those which can spur restorative action in the future.
The aluminum from the Milk Run AMD discharge is removed from the water before flowing back into the creek.