MADISON, Wis. (AP) — Utilities looking to finish building a high-voltage power line linking Iowa and Wisconsin completed a contentious land deal Thursday that allows them to build on a Mississippi River federal wildlife refuge.

American Transmission Company, ITC Midwest and Dairyland Power Cooperative have nearly finished the Cardinal-Hickory Creek transmission line. If completed, the 345-kilovolt line would stretch 102 miles (164 kilometers) from Iowa’s Dubuque Country to Wisconsin’s Dane County.

A mile-long section of the line (1.6 kilometers) would cross the Upper Mississippi River National Wildlife and Fish Refuge near Cassville, Wisconsin.

The refuge is a haven for fish, wildlife and migratory birds. Conservation groups filed a lawsuit in March seeking to block the crossing. They contend the U.S. Fish and Wildlife Service issued final approvals for the crossing without adequate public comment. They also allege that the fish and wildlife service and the utilities improperly reached a deal calling for the utilities to transfer about 36 acres (15 hectares) south of Cassville to the refuge in exchange for 10 acres (8 hectares) within the refuge for the line.

U.S. District Judge William Conley issued a preliminary injunction preventing the utilities and the agency from closing the deal, but a federal appellate court invalidated the order on Tuesday.

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Rodney Pritchard, a spokesperson for ITC Midwest, said the utilities and the agency closed the deal Thursday. He said it’s unclear when construction will begin.

The conservation groups fear construction will begin immediately. They asked Conley on Thursday to issue another injunction. The judge has set a hearing for Tuesday.

The groups’ lead attorney, Howard Learner, said in a statement that he hopes the utilities won’t begin construction before Tuesday’s hearing. He said the groups deserve their day in court.

Officials with the fish and wildlife service declined to comment because the legal case is ongoing.