The passive coal mine remediation system at Wingfield Pines Conservation Area (Bridgeville, Pennsylvania) failed following a November 2017 rupture of the mining cavern it contained. The event caused a ~2000 gallon/min abandoned mine drainage (AMD) flow to bypass the remediation system, directly entering Chartiers Creek between November 2017 and September 2019. The system was observed during the last 7 months of its ~2-year dormancy and simultaneous repair, which drained the system of water. Personal observation, testimonies, and photographic evidence were analyzed to identify changes in vegetation, flow, and function of the system pre-rupture (2017) and post-repair (November 2019). Major physical and chemical changes occurred in the system and mining cavern during its dormancy, which may affect its function and remediation of AMD well into the future. The ~2-year dormancy of the system acted to dry the saturated AMD-sludge, which accumulated at the bottom of the ponds, allowing opportunistic vegetation to spread throughout the ~20-acre system. Despite receiving no direct influent and the absence of water in previous and subsequent ponds, pond 4 retained water during the ~2-year dormancy. This suggests an alternate water source supplies pond 4 of the system. After water was returned to the system, vegetation accumulated and showed visual evidence of decay at the influent of each pond except pond 4. The physical and chemical alterations to the system have the ability to both directly and indirectly impact conditions such as flow rate and pattern, dissolved oxygen, temperature, and pH. Exposure of the anoxic sediments within ponds 1, 2, 3, and 5 likely caused the species they contain to become completely oxidized. In the context of AMD remediation, the alteration of multiple biotic and abiotic factors has the potential to cause complex changes to microbial community composition and chemistry at Wingfield Pines. Furthermore, these changes may act to alter the function and remediation efficiency of Wingfield Pines passive remediation system as compared to 2017.

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This work is licensed under a Creative Commons Attribution 4.0 License.