Repairs to a sinkhole on Interstate 26 near Ridgeville are expected to delay traffic Friday, but the extent of the slowdown will depend on how the work goes, officials said.

“Both eastbound and westbound lanes will be slow but they are not going to be shut down,” said James Law, spokesman for the state Department of Transportation.

Late Thursday afternoon, the eastbound passing lane re-opened but the westbound passing lane remained closed and was expected to stay shut because a crane was located there. The eastbound fast lane could be closed at times Friday, he said.

The sinkhole in the eastbound passing lane was discovered July 5. It was filled with rocks, and a steel plate was put over it. But the problem worsened, so two truckloads of concrete were pumped into the sinkhole Thursday. During the work, traffic backed up for at least seven miles because passing lanes in both directions were shut down, Law said.

The sinkhole is at Mile Marker 192.5. How long the major repairs to the road will take was uncertain.

“We don’t know the extent of the problem yet,” Law said.

The possibility of the same sort of problem in the westbound lanes is a concern, he said.

The sinkhole affects the width of the eastbound fast lane, he said.

The crane in the closed westbound lane was being used for installation of sheet metal pilings and sheet planking to facilitate the repairs, Law said.

Heavy rain washed away soil beneath a 10x10-foot-wide drainage culvert located under the interstate. The loss of soil beneath the culvert contributed to formation of the sinkhole, he said.

In South Carolina, sinkholes are relatively rare but they have been reported from time to time.

In May, Georgetown County Council hired a consultant to assess how much damage sinkholes caused to the county Judicial Center Complex and the Georgetown Library.

Sinkholes began appearing in Georgetown in late October 2011. At the time, up to 60,000 gallons of water per hour were being removed from the ground as part of a state DOT drainage project, The Georgetown Times reported.

Damage was also reported at several other county buildings, including the Department of Social Services, the Magistrate’s Office and the Winyah Gymnasium.

Eleven years ago, a 15-foot deep sinkhole opened on the edge of a dirt road near Rosinville in rural Dorchester County. Holes that were 10 feet to 40 feet wide near Harleyville and in Berkeley County near Jamestown have been reported.