SAVANNAH, Ga. — Ben Redmond and Matt Christiansen are breathing a little easier now that the most dangerous part of their job is over.
The pair, along with a handful of engineers and technicians, spent the last two months inerting 170 Dahlgren and 6.4-inch Brooke projectiles that Navy divers recovered from the CSS Georgia this summer.
And though the projectiles were submerged for more than 150 years, the explosive threat was still very real.
“If there was a big fire, they would definitely ignite,” said Christiansen, a former Navy explosive ordnance disposal technician who functioned as the safety officer for the project.
He also said the munitions could explode if they were dropped or struck by a heavy object.
To mitigate this threat, the team employed a meticulous, multistep inerting process; a process that would earn MacGyver’s respect.
First, each projectile was lightly cleaned to determine the best area for drilling, then placed in a specially designed drilling tank filled with water.
Christiansen and Redmond positioned themselves 20 feet from the tank behind a half-inch thick, 4-by-8 foot steel plate. While looking through a 5.5-inch thick bulletproof window atop the plate, the pair used an iPad and GoPro camera to monitor and remotely drill a small hole in each projectile.
The hole allowed the team to extract the black powder that comprised the projectile’s bulk explosive.
“This is the only job like this I’ve seen,” said Redmond, a retired Marine Corps master EOD technician and senior technical consultant for the project. “Most inerting is done in an industrial setting, not in the field like this.”
Their abundance of caution was not unfounded, as the pair found dry black powder in an overwhelming majority of the projectiles.
Next, Stephen Pilcher and Spencer Nzengung, the project manager and engineer, respectively, ran each projectile through a series of steps that repeatedly soaked and flushed the black powder using MuniRem solution and high-pressure hot water.
The key to the entire process, though, was the MuniRem soak.
MuniRem is a solution that chemically neutralizes explosives, and was invented by Prof. Valentine Nzengung, Ph.D., an environmental engineer and environmental geochemist at the University of Georgia. He created the solution in 2005 but is continuously refining the compound to target different explosives.
Prof. Nzengung said MuniRem is unique, not only for its ability to chemically degrade or destroy munitions, but because the leftover waste water and sludge is nonhazardous.
“There are other chemical means for neutralizing munitions, but they end up with hazardous waste,” he said.
As workers flushed the munitions with hot water and MuniRem, the liquids carried black powder down a stepped trough system, which was built with 2-by-4s onsite.
The stepped system is a means for collecting progressively finer black powder particulates, which are then scooped and further contained.
After the bulk explosive is thoroughly soaked and flushed, Redmond and Christiansen remove the fuze and its charge.
According to Redmond, these 19th century projectiles aren’t too far removed from their modern-day counterparts, where a fuze ignites a small charge that triggers a reaction in the bulk explosive.
Following the inerting process, the projectiles were sent to Texas A&M University’s Conservation Research Laboratory for further conservation.
For more photos of the inerting process, visit our Flickr page.