One year after construction triggered a flood of spilled artesian groundwater, Enbridge Energy says it has pumped enough grout into the ground to seal the aquifer that crews punctured in northern Minnesota while building the Line 3 oil pipeline.
Enbridge told the state Department of Natural Resources (DNR) that it stopped the flow of groundwater at the site Jan. 18, according to a notice on the department's website. The DNR said it will monitor the repair to ensure it holds.
"In addition, the DNR continues to work on its ongoing investigation and a comprehensive enforcement resolution that will address restoration, mitigation, and additional penalties associated with Clearbrook as well as two other aquifer breaches," the department said in the posting.
The rupture was one of the worst environmental accidents during construction of the bitterly opposed 340-mile pipeline in Minnesota. There were 28 documented drilling mud spills and frac-outs, and state regulators are investigating two other aquifer breaches at undisclosed locations.
The White Earth Band of Ojibwe and other pipeline opponents are doing an independent investigation, including collecting drone footage, to check for further impact on water.
Last year's breach was made more alarming by the fact that neither the company nor independent monitors told state regulators until months after it happened. The rupture wasted huge volumes of groundwater, and the outflow endangered a rare calcareous fen, a protected wetland fed by groundwater.
The breach occurred near a large pipeline junction outside Clearbrook, Minn., in Clearwater County.
State regulators ordered Calgary, Alberta-based Enbridge to pay $3.3 million and fix the damage. The company missed a deadline in October and paid an additional $40,000. At that time, regulators estimated that at least 50 million gallons of groundwater had flowed out since the accident.