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C O M M I S S I O N N E W S R E L E A S E |
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COMMONWEALTH OF PENNSYLVANIA Helen Humphreys Short |
September 2, 2004 |
FOR IMMEDIATE RELEASE
DEP, TURNPIKE COMMISSION, ALLEGHENY COUNTY AIRPORT AUTHORITY ANNOUNCE COMPLETION OF MINE DRAINAGE TREATMENT SYSTEM NEAR FINDLAY CONNECTOR HIGHWAY PROJECT
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The six-mile toll road that will extend south from the state Route 60 Expressway at Pittsburgh International Airport to U.S. Route 22 in northern Washington County is under construction and targeted for completion in summer 2006. It will serve as part of the Turnpike Commission’s proposed Southern Beltway, which is to link eventually with Interstate 79 and the Mon/Fayette Expressway near Finleyville. The Turnpike Commission funded the $75,000 system after construction workers, as expected, encountered the polluted discharge percolating from an underground abandoned mine near the connector’s future interchange with U.S. Route 30. The commission’s general contractor for the middle third of the connector, Mashuda Corp. of Cranberry Township, Butler County, re-mined the abandoned mine land by removing the coal pillars left behind by the original mining operation and installed the drainage system. “We are very pleased with the work the Turnpike Commission has performed and with the cooperation of the Allegheny County Airport Authority in the installation of the settling ponds, which are located within the authority’s right of way,” said Michael Terretti, director of DEP’s District Mining Operations. “We also are pleased with the commission’s shared interest in seeing the discharge treated on a long-term basis, which we hope to assist in by funding the conversion of the settling ponds into wetlands.” The acidic, iron-laden discharge stems from an abandoned mine operated by the Clinton Block Coal Co. until 1936. The discharge is located just outside Imperial Borough, Allegheny County, and was pinpointed during geotechnical exploration conducted as part of final design work for the new highway. Mashuda’s removal of the coal pillars—and hence, the voids in between the pillars—should prevent future subsidence damage to the highway. Mashuda blasted a drainage trench in the mine floor and filled it with processed limestone. The company installed a partially open drain pipe on top of the trench. The drainage will travel through the limestone inside the trench in order for the limestone to increase the alkalinity of the drainage and cause the iron and aluminum to settle out. Once it flows through the trench, the mine drainage will flow into the settling ponds, where the metals will continue to settle out. The water will then be discharged into a tributary of Montour Run. After about 20 to 25 years, DEP expects the limestone to be fully coated with iron and aluminum and rendered ineffective. At that point, the drainage will begin to flow on top of the coated limestone and into the concrete drainage pipe, which will then take the discharge to the settling ponds. The concrete itself will help increase the alkalinity of the discharge. “This was a situation where our engineers and Mashuda’s staff decided it would be preferable to craft a longer-term remediation plan instead of adhering strictly to the regulations, which mandated that we treat the discharge only during the highway construction period,” said David P. Willis, the Turnpike Commission’s environmental manager. “This is the best solution for all stakeholders and it’s much more cost-effective.” Mashuda already has pumped out and treated the mine pool found inside the abandoned mine. The discharge continues to flow from the mine at a rate of about 150 gallons per minute. For more information, visit the department’s Web site at www.dep.state.pa.us.
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P.O. Box 67676, Harrisburg, PA 17106-7676 Phone: (717) 939-9551 Fax: (717) 986-9649 |
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