Effect of Longwall Mining on Pennsylvania I-70

A longwall mine was constructed beneath I-70 near the Pennsylvania-West Virginia border between December 2018 and March 2019. This resulted in over a 4-ft drop in the elevation of parts of the roadway. The Pennsylvania Department of Transportation was able to maintain the roadway open to traffic throughout the subsidence period after it was undermined. This paper will describe the steps taken by PennDOT to ensure the roadway could stay in service throughout the subsidence event with minimal traffic disruptions, the subsidence basin that developed as a result of mining, and the distresses that developed within the pavement structures as a result of the subsidence.