The Monroe solar farm is a privately owned 35-acre site which historically operated as a clay mine from the 1950’s until the early 2000’s. Backfilling of the mine occurred concurrent with mining starting in the 1970’s, with the majority of backfilling operations taking place prior to modern NJDEP clean fill guidance and standards. RT completed a Preliminary Assessment and Site Investigation, which confirmed the presence of historic fill at the site, and a small, previously closed coal ash landfill. Following consultation with NJDEP, RT completed a Remedial Investigation to determine whether or not backfill materials constituted an unpermitted solid waste facility. The investigation evaluated fill materials up to 45 feet below ground surface to the mined elevations. RT concluded, and NJDEP concurred, that the site was backfilled with historic fill and could proceed with remediation under the Contaminated Site Remediation and Redevelopment Program (formerly the Site Remediation Program).