Hundreds of Civil War relics were unearthed during the cleanup of a South Carolina river where Union troops dumped Confederate military equipment to deliver a demoralizing blow for rebel forces in the birthplace of the secessionist movement.

The artifacts were discovered while crews removed tar-like material from the Congaree River and bring new tangible evidence of Union Gen. William T. Sherman's ruthless Southern campaign toward the end of the Civil War. The remains are expected to find a safer home at the South Carolina Confederate Relic Room and Military Museum in the state capital of Columbia.

Historical finds include bullets, cannonballs and even swords, CBS affiliate WLTX reports.

Also discovered was a wheel experts believe belonged to a wagon that blew up during the two days of supply dumps. The odds of finding the wagon wheel "are crazy," according to Sean Norris.

"It's an interesting story to tell," said Norris, the archaeological program manager at an environmental consulting firm called TRC. "It's a good one - that we were able to take a real piece of it rather than just the written record showing this is what happened."

One unexploded munition got "demilitarized" at Shaw Air Force Base. Norris said the remaining artifacts won't be displayed for a couple more years. Corroded metal relics must undergo an electrochemical process for their conservation, and they'll also need measurement and identification.

Dominion Energy crews have been working to rid the riverbed of toxic tar first discovered in 2010, at times even operating armor-plated excavators as a safeguard against potential explosives. State and local officials gathered Monday to celebrate early completion of the $20 million project.

"We removed an additional two and half tons of other debris out of the river. You get focused on coal tar and yes we took care of the coal tar but you also had other trash," Keller Kissam, Dominion Energy President said, according to WLTX.

South Carolina Republican Gov. Henry McMaster said this preservation is necessary for current generations to learn from history.

"All those things are lost on us today. They seem like just stories from the past," McMaster said. "But when we read about those, and when we see artifacts, and see things that touched people's hands, it brings us right back to how fortunate we are in this state and in this country to be where we are."

Previously found war relics

Relics from the Civil War have been discovered in South Carolina before. In 2016, Hurricane Matthew unearthed Civil War cannonballs from the sand on Folly Beach. A similar discovery was made by a couple on the same beach three years later after Hurricane Dorian.

Last year, in neighboring Georgia, 19 cannons were found in "amazing condition" in the Savannah River. Experts said the cannons likely came from British ships scuttled to the river bottom during the American Revolution.

In 2015, wreckage of the Confederate warship CSS Georgia was raised to the surface of the Savannah River. The vessel was scuttled by its own crew to prevent Gen. Sherman from capturing the massive gunship when his Union troops took Savannah in December 1864.

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• South Carolina
• Civil War