The latest sinkhole on a Morris County interstate, based on preliminary inspections, looks to be caused by an abandoned pipe.

The problems on Route 80, including the latest sinkholes, can be traced back to mining activity more than two centuries ago.

Portions of Interstate 80 in Morris County have been closed for four months due to sinkholes. Timothy Bechtel, a senior professor of geosciences at Franklin & Marshall College, said precipitation ...