Motorists may be able to drive across Old County Road by the end of the month.

Mike Burns, the acting Maine Department of Transportation director for the maintenance and operations bureau, told the Rockland City Council March 8 that an excavator would be on site March 9 to begin the work.

The $250,000 estimated cost of the work will be borne by the state.

The project will consist of filling the approximately 70-foot-deep hole with granite blocks and then covering it with gravel.

Utility lines will be relocated, a berm will be removed, and a guardrail will be erected, Burns said.

The sinkhole developed on Feb. 15 and grew over the weeks. The road has been closed off since then with concrete barriers and a fence. A tunnel located under the road leads to an adjacent former limestone quarry now owned by the state.

Burns said ground penetrating radar indicated some water running under the road but not a lot.

Burns did caution the council, however, that another cave or tunnel was located under Old County Road, slightly north of the sinkhole. The transportation department will do some test boring to determine if that is also at risk of collapse. The tunnels were dug from the sides of the former limestone quarry more than 100 years ago.

The Rockport Fire Department has agreed to respond to any fires in the Rockland section on the northern side of the sinkhole until the road is reopened. Rockland police continue to patrol the area, using Route 1 to Rockport and then traveling back along Old County Road.

The sinkhole has even spurred the creation of a Facebook page by people affected by the closure. The page is titled “Survivors of the Rockland Sinkhole.” As of March 8, it had 249 members who were commenting back and forth on the sinkhole.