MADISON, Wis. (AP) — Utility companies have started construction on a contentious power line crossing in a Mississippi River wildlife refuge.

ITC Midwest and Dairyland Power Cooperative are looking to string the final mile (1.6 kilometers) of the Cardinal-Hickory Creek transmission line across the Upper Mississippi River National Wildlife and Fish Refuge near Cassville, Wisconsin. When finished, the 102-mile (164 kilometer) line will link Iowa’s Dubuqe County and Wisconsin’s Dane County.

A coalition of conservation groups sued in March to block the refuge crossing and won a preliminary injunction from U.S. District Judge William Conley. The 7th U.S. Circuit Court of Appeals stayed the injunction on May 7, however, clearing the way for construction to begin. The utilities said in a joint statement that preliminary construction work began Monday with tower footings slated to be poured the week of May 27.

The conservationists have asked Conley to issue another preliminary injunction. Conley held a hearing on the request Tuesday but didn't rule on it. He said he remains concerned about damage the line could cause to the refuge but the reality is the line will be completed and cause damage somewhere.