© APFrozen: U.S. Coast Guard a convoy of Great Lakes cargo ships line up to follow an icebreaker on the St. Marys River, which links Lakes Superior and Huron. U.S. Steel said Monday, April 7, 2014 that its largest mill in Gary, Indiana, is on limited production because of a lack of raw materials
Traffic remained largely at a crawl after a winter that produced some of the heaviest ice on record across the five inland seas, where more than half the surface area remained solid this week.
Icebreaking ships slogging across Lake Superior were still encountering ice layers 2 feet to 3 feet thick. In some areas, wind and wave action created walls of ice up to 14 feet high.
United States Steel Corp.'s plant in Gary, Indiana, had resumed limited operations after receiving a shipment over the weekend of iron ore from a company mill near Detroit, which was sending one additional load, spokeswoman Courtney Boone said.
Two ships were scheduled to arrive Tuesday with ore from mines in northern Minnesota following a two-week voyage across Lake Superior, which ordinarily would take three days.
Other companies were hoping their supplies would be adequate to avoid significant disruptions.
'Nobody's stockpile situation is very good,' said Glen Nekvasil, a spokesman for the Lake Carriers' Association, which represents companies that operate 57 U.S.-flagged freighters on the Great Lakes. 'It's still very slow sledding.'
© ReutersPolar vortex: A ship is frozen in Lake Superior at port in Superior, Wisconsin on February 15, 2014. According to the National Oceanic and Atmospheric Administration (NOAA) Great Lakes Environmental Research Laboratory, about 94% of Lake Superior was covered with ice this winter
The Gary Works mill generates steel for industries such as construction and auto manufacturing. Production resumed at one of the mill's three furnaces after Sunday's shipment was received, Boone said.
The Gary Works is capable of producing 7.5 million tons of steel per year.
U.S. Steel was able to operate off stockpiles for some time before the ice began affecting production, Boone said.
Charles Bradford, a steel industry analyst, said the company should have done better planning even though this winter was among the harshest in recent memory.
© APCoast Guard Cutter Biscayne Bay, a 140-foot ice-breaking tug, sails through ice covered waters toward the shores off Indiana as U.S. Steel said on Monday, April 7, 2014 that its largest mill in Gary had to halt production over the weekend
© APProduction: U.S. Steel's sprawling Gary Works plant in Gary, Indiana sits a short distance from Gary's City Hall
'They know that every winter the Great Lakes freeze over,' Bradford said. Boone declined to comment.
The shipping season officially began two weeks ago with the opening of navigational locks on the St. Marys River connecting Lakes Superior and Huron, a bottleneck for vessels hauling iron ore and coal to manufacturers and electric power plants.
But just one convoy of vessels - including two icebreakers and the two ships hauling iron ore - had traversed Superior with loads of freight.
Two other coal haulers were docked in Superior, Wis., waiting to make deliveries to a power plant in Marquette, Mich., said Mark Gill, director of vessel traffic service for the U.S. Coast Guard in Sault Ste. Marie.
Five empty vessels were expected to begin crossing Lake Superior on Tuesday to pick up iron ore.
© ReutersRevelations: Sightseers trek across a frozen expanse of Lake Superior, the world's largest freshwater lake, to the sea caves of the Apostle Islands National Lakeshore near Cornucopia, Wisconsin on February 15, 2014
Even so, there wasn't enough demand to disrupt service, he said. The plant serves about 22,000 customers, mostly in Michigan's Upper Peninsula.
DTE Energy, which operates five coal-fired plants in southeastern Michigan, has dealt with dwindling stocks by taking some units out of production for maintenance ahead of schedule and making up for the loss by buying power from the grid, spokesman Scott Simons said.
'This will hold us over until we can rebuild our supplies,' Simons said.
General Motors has not had any delays or material shortages because of Great Lakes shipping problems, spokesman Tom Henderson said.
Nine U.S. Coast Guard ships are capable of breaking ice but only one, the Mackinaw, is equipped to deal with the thickest formations, Gill said.
The Canadian Coast Guard dispatched two heavy-duty vessels to assist.
About three-quarters of Lake Superior, the largest and deepest of the Great Lakes, remained ice-covered.
Gill estimated it would be about two weeks before the surface is clear enough for freighters to make the crossing without an icebreaker escort.
Even then, the icebreakers probably will be on duty well into May and possibly as late as Memorial Day.
'We'll be constantly on search-and-destroy missions, finding big pieces of ice and breaking them into smaller pieces,' Gill said.
They might want to stock up on those.