The U.S. Army Corps of Engineers is planning maintenance work on the navigational lock system at Sault Ste. Marie, which has shut down for the winter.
The Soo Locks closed last week, halting most cargo shipping on the Great Lakes. They'll reopen in mid-March.
The Army corps says its crews will install hydraulic pump units for the Poe Lock operating gates and make other improvements and repairs.
Vessels make more than 4,500 trips through the locks annually, hauling 80 million tons of freight including iron ore, coal, limestone and grain.
The Lake Carriers' Association represents 17 American companies that operate 57 U.S.-flag vessels on the Great Lakes. The organization says its members will spend $70 million tuning up the fleet during the winter break.