Johnstown South Remediation

The PA DEP Bureau of Abandoned Mine Reclamation (BAMR) contracted Larson Design Group (LDG) to produce a design to eliminate public health and safety hazards associated with abandoned mine land in Problem Area 2477, otherwise known as Johnstown South. The project, located in the City of Johnstown and Southmont Borough in Cambria County, PA, is a direct result of underground coal mining by the Cambria Iron Company’s Rolling Mill Mine, which later became Bethlehem Steel’s Mine 71, which ceased operation by 1940. Steep slopes, an unknown volume of water potentially being impounded in the mine pool, a tunnel roof collapse, and the unknown condition of piping from the concrete drop structure to the discharge point all contribute to the abandoned mine’s safety hazards.

To address the public health issues at Johnstown South, LDG’s project design includes demolition and excavation for the removal of the abandoned concrete tipple, the existing tunnel entry, and the existing terracotta conveyance pipe entry headwall. Consistent with another LDG-BAMR project at Spangler Athletic Field, the design will continue excavation from the tunnel entry to reach the roof collapse and vertical opening. Perforated pipe will be driven into the tunnel 10 to 15 linear feet beyond the vertical opening to restore function of the drainage tunnel. A seal around the new drainpipe will consist of stone and a clay cap. New piping will be installed to replace the existing terracotta drainage pipe that connects to the concrete drop structure with cleanouts at vertical and horizontal changes in pipe alignments. Finally, cleaning, flushing, and CCTV investigation of the condition of the remaining piping to the outfall will be conducted.

The site will be backfilled to eliminate the existing tunnel entry portal and vertical opening to remediate the dangerous conditions of the abandoned mine. LDG will incorporate safety and environmental concerns into the design, ensuring the final outcome of a safe discharge rate upon excavation at the location of the tunnel roof collapse and drain clog. The conveyance piping under Franklin Street to the discharge at the Stonycreek River will be flushed and investigated to determine if it is able to be repaired or lined, or whether it requires replacement. LDG estimates project design completion by December 2025.