The site is a 72,846 square meter (18-acre) abandoned strip mine located in Western Pennsylvania used for municipal and industrial waste disposal until the mid-1970’s. The waste pit is adjacent and connected to a flooded deep mine which saturated the waste over the past 20 years. The site was placed on the National Priority List in 1984, primarily due to the presence of drums on the surface of the site.
EPA’s proposed remedial action for the site included excavation and stockpiling of the waste materials, backfilling the pit with clean materials, constructing a RCRA cell on the clean materials, and disposing of the waste into the cell. The estimated cost of EPA’s remedy was approximately $26 million. An alternative action proposed included in-place closure and containment at the site. Many were unsure whether a slurry cutoff wall could be installed through the deep mine adjacent to the waste pit. The proposed alternative of grouting mine voids to facilitate slurry wall installation had never been performed on a Superfund site, and resulted in a cost savings of approximately $15 million. The grout and slurry wall were successfully installed, with complete closure expected by spring of 1997.