The Solar Mine Discharge is located in Findlay Township, Allegheny County, near Bald Knob. This discharge resulted from construction of Section 54C of the Findlay Connector, part of the Pennsylvania Turnpike Commission's Southern Beltway project. The settling ponds of the treatment system are visible from the road shoulder, just past the Bavington-Santiago Exit of I-576 westbound. The bulk of the treatment system is a large limestone bed called an Anoxic Limestone Drain or ALD which lies deep under I-576. As the mine water passes through the ALD, iron is removed by chemical reaction with the limestone. Water then flows to the ponds and wetlands where even more iron settles out.
The Solar Mine Treatment System removes about 96 tons of iron yearly from the headwaters of St. Patrick's Run, a western tributary to Raccoon Creek. In 2007, Independence Conservancy retained Hedin Environmental of Pittsburgh to assess existing site conditions and develop maintenance strategies to maximize the useful life of the system. $25,000 in funding for the engineering study was provided by Canaan Valley Institute. Hedin found that the system is highly effective at removing iron and reducing acidity, and, with proper maintenance, should remain functional for another 30 years or more.