Cargo moved at the Port of Vicksburg doubled in a month’s time, thanks to continued mineral ore shipments by DuPont, officials said Monday.

Loads of ore, steel coils, lumber and soybeans totaled 29,323 tons in September, up from 14,443 in August. Ore made up two-thirds of the month’s load and results from the chemical products and services company’s deal with Kinder Morgan to use the port as a hub to ship raw material through next fall.

“The biggest part of it is the DuPont business,” said Tom Murphree, Kinder Morgan regional sales manager. “Second to that, we’ve recovered some old business that we had at one time, such as running aluminum to Delhi.”

Pressure to preserve a deal with DuPont prompted the county in April to extend Kinder Morgan’s lease to operate the port through June 2013.

Murphree said steel coils recorded for the month were shipped to Severstal, a continuing relationship that shaped two years of contract talks at the port that ended in 2009 with Kinder Morgan’s current base deal.

“I’m in hopes that will be a continuous thing,” he said, adding an overall slump at the port since the T-dock was replaced and the onset of the recession may have “bottomed out.”

Shipments have totaled about 52,000 for the year, far off the pace of the 161,222 unloaded in 2010 and is certain to be a fourth consecutive year of declining loads. Work ground to a halt in May as the Mississippi River’s historic crest backed up into the slack-water harbor and had the dock and rails underwater.

Damage to two office spaces and restrooms in a terminal warehouse is estimated between $25,000 and $30,000, port commission executive director Wayne Mansfield said, adding the commission will seek to be reimbursed by FEMA for all repairs.