Cannonballs galore: They were turning earth for condos in Pittsburgh and came across cannonballs at site of Union arsenal. A lot of it.

Dozens of artillery rounds at site (Pittsburgh Police Facebook post)

A construction crew building condominiums in Pittsburgh last month came across a cache of artillery rounds near the site of an arsenal that supplied the Union army during the Civil War.

Pittsburgh police on Thursday posted photographs of the July 2 find in the Lawrenceville area while crews were turning soil. The number of shells has not been determined. Police described the cannonballs as live.

Jack Melton, who publishes the Civil War News and the Artilleryman magazine, told the Picket the rounds are 12-pounder cannonballs with Bormann fuses.

“Thankfully, this excavator operator had some prior experience and promptly called the Pittsburgh Police Bomb Squad when he recognized what his machinery had hit; a cache of Civil War era cannonballs," police said on Facebook.

“This was the same employee who had helped unearth 715 cannonballs while working not far from here in March of 2017, the site of the former Allegheny Arsenal, an important supply and manufacturing center for the Union Army during the American Civil War.”

Some Facebook commenters say this is a Bormann time fuze.

The Facebook post said the rounds are the property of the Army, and police will handle “mitigation” in coordination with the military. It’s not immediately known whether they will be destroyed.

According to the Pittsburgh Post-Gazette, the discovery is not unusual for the area, located at the site of the U.S. Allegheny Arsenal, which produced 128,000 rifle cartridges a day for Union troops during the Civil War. 

In 1862, 78 people were killed when three explosions erupted in a building called the laboratory. It was one of the worst civilian disasters during the Civil War, according to the newspaper. 

Ground was being turned for construction (Pittsburgh Police)

Police told the Post-Gazette they kept the discovery quiet so that the rounds could be removed without endangering the curious. They had no map or drawings from which to work.