In a typical year, more than 12 million tons of iron ore, most of it mined in Minnesota, would have been shipped across the Great Lakes by now.

But just 8 million tons have made the journey since the Soo Locks opened in March in one of the slowest starts for taconite shipments in recent history.

Steel mills are running at levels similar to last year, which normally would indicate a steady stream of ore floating down the lakes.

"That relationship hasn't played out in typical fashion so far this shipping season," said Duluth Seaway Port Authority spokesman Jayson Hron.

The movement of ore-hauling ships across Lake Superior was hampered by ice in March and April, but May's open-water results show the demand for taconite pellets to make steel isn't where it used to be. May shipments were 20% below the year before and 22% off the five-year average, according to the Lake Carriers' Association.

Earlier this year Cleveland-Cliffs CEO Lourenco Goncalves said "our iron-ore needs are not as high as before," indicating the below-average shipment numbers may be a new normal.

Cliffs controls the majority of Iron Range taconite production via the Minorca, Hibbing Taconite, Northshore Mining and United Taconite mines. But the company has taken several steps in the past year that will reduce production.

Northshore Mining was idled on May 1 to be a "swing" operation, in part to avoid paying royalties for iron mined in Babbitt and processed in Silver Bay.

The company also acquired a scrap-steel firm last fall and has stopped selling iron ore to third parties.

Cliffs did not respond to a request for comment.

As sky-high steel prices boosted profit, but overall production declined, Goncalves told investors in April that "tonnage is not the answer, the answer is profitability, the answer is cash flow, the answer is generating shareholder value; that's what we're doing at Cleveland-Cliffs."

U.S. Steel, which runs the Keetac and Minntac mines, said in a news release Thursday it expects a hefty profit in its second quarter and "increased demand across our diverse customer base is expected to result in higher shipment volumes" for steel.

"Each business segment [is] meaningfully contributing to profitability," CEO David Burritt said in a statement.

Hron noted "the pace appears to be quickening" after a rocky start to the iron-shipping campaign.

"It's too early to predict end-of-season totals after a late start and only two months of shipping, but there are clearly headwinds," Hron said, "including supply-chain issues affecting automobile and appliance manufacturing, inflation affecting consumer spending, and high transportation [fuel] prices affecting the movement of cargo, just to name a few."