Geophysicists used ground penetrating radar at Detroit's historic Woodlawn Cemetery on Thursday. 

Archeologists use the technology to better chart the locations of graves, but what they're finding are some resting places that no one even knew were there. 

"In a 10-hour day, I'll walk about 13 miles," said Joseph Snider, a geophysicist with Terracon.  

The contraption that sort of looks like a lawn mower is a ground penetrating radar. Snider's colleague and fellow geophysicist, Alexander Corkum, said teams are working on the first step in creating detailed imaging of Woodlawn Cemetery.

"This is a 250 megahertz antenna. We're doing a gridded survey tied in with a RTK-GNSS; it's a very precise GPS basically, and it allows us to accurately locate our data in the real world," said Corkum. 

In the past, Woodlawn Cemetery was the only place in the area that would accept Black bodies, so there's a lot of history to uncover.  

Historians say the goal is to get a better understanding of where graves are located on the historic grounds.  

"Even from the initial survey, there are graves father back than we thought at the beginning, so this data is so so critical," said Debby Covington, president of the African American Cultural and Historical Museum of Washtenaw County. 

Covington, alongside historians, community members and archeologists, is planning to excavate the grave stones that have been lost to time. 

"We are truly restoring this cemetery, hopefully even greater than it was originally," said Covington. 

It'll take another two days at least for Snider and Corkum to use the radar on the nearly three acres of land on which the cemetery sits. Next spring, Corkum said, scientists from across the country will come to work on Woodlawn. But according to Kat Slokum, who is helping lead this project with Covington, that's not all. 

"We're also working to get this site listed on the National Register of Historic Places and as a local historic district to protect it in perpetuity," said Slokum.