Rumbles of trucks hauling clay to cap off parts of the defunct Vicksburg Chemical plant off Warrenton Road will become a common sound starting Monday and continue for the balance of the year, as a comprehensive site cleanup enters a fifth year.

About 20 acres of land near the old plant entrance on Dabney Drive will be about a foot higher a year from now, if current cleanup schedules hold — a result of a new topcoat of clay to trap harmful materials below the surface, said Trey Hess, project manager for the Mississippi Department of Environmental Quality.

“We’ll put watertight fill material such as clay as a liner to cap the contaminants in the soil and protect the water table so the land can eventually be redeveloped,” Hess said.

The acreage comprises what was the south plant of the chemical processor, which operated under various owners until buried hazardous waste was discovered in the 1990s. Its last owner, Cedar Chemical Corp., went bankrupt in 2002. The cleanup begun in 2006 and pegged by the state at $8 million has continued as part of an agreement between MDEQ, London-based consultancy firm ARCADIS and what’s left of the Mississippi Bluffs development firm.

The company had agreed to help pay for ARCADIS to clean up the most contaminated 20 acres of former plant property while its lead developer, Paul Bunge, spearheaded plans to build a casino and golf complex on another 480 acres of wooded land formerly owned by the chemical maker. Plans to build the 50,000 square-foot riverside casino and an adjacent 18-hole golf course fell through in December 2007 when Bunge died and potential investors in the casino dropped out of the project.

Mississippi Bluffs Industrial Park LLC is the holding company for the south plant property. Mississippi Bluffs Development LLC is the listed owner of where the casino and golf course were planned. Assets of both are now handled by a mishmash of financial advisers and gaming development firms.

Vestiges of the plant’s infrastructure are gone. A reactor tower, two ammonia spheres and an above-ground fuel tank were demolished more than two years ago. The clay and other plant-sustaining earthen material used to cap the site should keep storm water from percolating through soils contaminated with hazardous materials such as arsenic and dinoceb, a pesticide — thus keeping the contaminants from affecting groundwater, Hess said.

The land will be graded to allow most runoff to flow west of the site near an old sludge collection area where Hennessey and Stouts bayous connect. A series of extraction wells will be installed to pull and prep wastewater collected at the site for final treatment at the City of Vicksburg’s municipal treatment plant nearby.

Extensive dirt work on the hilly terrain surrounding the south plant site is a near-certainty once a developer is found. The shorter-term problem of dirt-hauling trucks around residential areas close to the old plant that are not truck routes will be addressed, Mayor Paul Winfield said.

“I expect to have more truck traffic,” Winfield said. “We’ll make sure we have increased presence there. I’m just hoping that tract of land moves. I’m confident that it will.”

While U.S. 61 South is the main truck route south of town and Rifle Range and Warrenton roads are not, city crews will work with ARCADIS to find alternatives to minimize road damage and traffic hazards, Public Works Director Bubba Rainer said.