Quarry Is Being Reinstated After 25 Years, Then Crew Members Find This

Carl knows more

The crew leader stood inside the object. It was a weird doorway about three feet deep, with a clear entrance and exit door. Carl’s team was confused, but Carl was a bit older and had seen some construction gear in his days. He knew that this was a tunnel door. They used it to strengthen tunnels, holding up tons of ground above while providing passage through dug-out areas.