Cargo shipped along the Great Lakes/St. Lawrence Seaway surged 13 percent in August with help from robust taconite shipments originating from Minnesota’s Iron Range, according to an international report issued Thursday by the Chamber of Marine Commerce.

Total tonnage shipped through the Great Lakes and St. Lawrence since March 20 jumped to 19.9 million metric tons, chamber officials said. That includes iron ore, salt and general cargo.

The boost was a relief, and further proof that the recovery of Minnesota’s previously clobbered iron-ore industry has progressed since 2015 and 2016, the years when seven ore processing plants in the state responded to the global downturn by idling plants and laying off thousands of workers.

Thursday’s report made it clear that ore and other manufacturing businesses were back.

In a statement, Marine Commerce Chamber President Bruce Burrows said “Given current North American economic conditions, we’re optimistic that Seaway cargo levels will top last year’s performance.”

Burrows said iron ore shipments alone had reached 4.7 million metric tons so far this year.

That’s “up nearly 54 percent from a year ago as ships carry iron ore pellets from the port of Duluth-Superior to Canada and onwards for export,” he said. What has helped is that “U.S. iron ore exports to Asia continue at a brisk pace along with shipments of steel, aluminum and oversized equipment and machinery to support manufacturing in U.S. cities across the Great Lakes region.”

Adele Yorde, spokeswoman for the Duluth Seaway Port Authority, said the ore increases chronicled in the August Marine report have been seen all summer from her perch in Duluth.

“It’s been a strong year. July shipments alone were up nearly 80 percent over last year,” she said. A good chunk of that Minnesota iron ore is being shipped to Canada. From there it either goes directly to Canadian customers or is reloaded onto ships headed to China, Japan and other overseas markets, Yorde said.

Earlier this month, Minnesota Department of Employment and Economic Development (DEED) Commissioner Shawntera Hardy reported that Minnesota’s iron ore, slag and ash exports tripled to $112 million during the second quarter.

One key reason? U.S. Steel.

The company reopened its idled Keetac taconite plant in Keewatin earlier this year. The plant, which suffered from depressed global pricing and the impact of illegal steel dumping, had shut its doors in May 2015, displacing more than 400 workers.

However, the plant reopened in January and February amid new ore orders from a Canadian steel mill customer. State officials noted that tons of Keetac taconite is again making its way through the Great Lakes into Canada.

Thursday’s Chamber of Marine Commerce report noted that shipping increases by Keetac and others in August are benefiting ports in Canada, Duluth and Toledo, Ohio. The port of Toledo in Ohio increased iron ore and coal shipments, which helped boost its total tonnage 43 percent from a year ago.

With increased manufacturing and shipping activity, chamber officials found that Great Lakes and Seaway ports are investing in infrastructure and marketing, which is “paying off with a more diversified cargo mix,” Burrows said.

In addition to ore, shipments of steel, aluminum ingots, project cargo and containers also rose 40 percent in August. One particular area of growth was for aluminum ingots used in auto manufacturing. More ingots were transported by barge this summer from Quebec to Oswego, N.Y., Detroit and Toledo.

The chamber also found that salt and other dry bulk cargo jumped an impressive 46.7 percent in August from a year ago.