Sinking of ground above a mine may be best known in Ohio as a coalfield problem, but the Ohio Department of Transportation now is taking precautions against road depressions or sinkholes becoming an issue along State Rt. 2 in eastern Ottawa County, where gypsum rock once was mined underground.
Starting soon -- perhaps as early as Friday -- a state contractor will string coaxial cables beneath part of Rt. 2 in Portage Township that will serve as sensors for any shifting beneath the roadway that could cause dips or even sinkholes in the pavement like one that closed part of I-70 above an abandoned Guernsey County coal mine in southeast Ohio for three months in 1995.
Portage Township's old gypsum mines, now mostly flooded, "are a strong suspect for problems in that area," said Todd Audet, the department's district deputy director at the Bowling Green office.