Carnegie Mellon University

Evaluation of Natural Amelioration of Acidic Deep Mine
Discharges for Watershed Restoration

Sponsor: U.S. Environmental Protection Agency

Principal Investigator: David A. Dzombak, Ph.D., P.E., DEE

Carnegie Mellon University, Pittsburgh, PA 15213

Project Period: October 1, 1997 - September 30, 2001

Uniontown Syncline AMD Discharge Monitoring, 1998-2000

Overview

The project involved study of a set of mine water discharges associated with abandoned, interconnected mines in the Uniontown-Connellsville area of Western Pennsylvania.  Almost all the deep-minable coal was removed from this area prior to 1970, and an extensive baseline study of mine discharges in the area was conducted in 1974-1975 as part of Operation Scarlift.  Additional water quality monitoring was performed from 1998-2000 at 21 of the sites studied previously.  This enabled assessment of the degree of mine water quality improvement since 1974-1975.  The local environments for each of these 21 discharges were also studied to relate observed changes in mine water quality to factors such as the extent of mine flooding and the chemistry of the rock overlying the mined area. 

 

Uniontown Syncline AMD Discharge Monitoring Network, 1998-2000

Field reconnaissance was performed to locate the monitoring sites used in the 1974-1975 study.  Our efforts were aided by information provided by the Pennsylvania Department of Environmental Protection, USS Mineral Resources, and mining engineers in the study area.  Following location of the sites, property owners were identified and contacted to request permission for monitoring.  Some preliminary flow and water quality monitoring was performed at approximately 30 locations in the summer of 1998.  Selection of final monitoring locations, and of groups of locations for composite monitoring, was made based on these results and on assessment of the usefulness of particular locations with respect to the overall project goals.

 

The Uniontown-Connellsville basin proved to be an excellent location for study of natural amelioration of mine drainage, as the basin includes both completely and partially flooded areas.  The degree of flooding has a major influence on mine water discharge quality.  The oval-shaped basin is divided across its short axis by the Youghiogheny River which serves as the major surface drainage stream.  South of the Youghiogheny River, the abandoned mine workings are completely flooded, while north of the river mining was conducted “updip” and the mine workings are free draining and not completely flooded. 

 

The monitoring network used in 1998-2000 included 19 individual discharge sites plus two in-receiving-stream sites at eight different locations in the basin.  Five of the discharge locations were from the deep, flooded mine complex on the south side of the Youghiogheny River, while three were in free-draining locations on the north side.  At 14 of the monitoring sites, permanent weirs were installed for monitoring of flow.  For the remaining sites, flow was measured via bucket and stopwatch, portable flume, or flow meter.  Flow measurements and water chemical analyses were performed monthly for each of the 21 monitoring sites.  In addition, in-mine water elevation and quality on the south side of the Youghiogheny River was monitored through monthly sampling of two existing minewater wells.

Locations and flow/chemical data for discharges north of the Youghiogheny River, 1998-2000

Locations and flow/chemical data for discharges south of the Youghiogheny River, 1998-2000

 

Last Updated: 10/18/02