Employees from surrounding businesses heard interesting noises from behind Burger King in Glen Rose Tuesday morning.

The noise resulted from a machine taking core samples from the earth below the local restaurant. An engineering and environmental firm, Nova Consulting, Inc., is doing a study of the property, which once housed a service station.

City Superintendent Ronald Bruce, who spoke with Nova representatives Tuesday, said the samples are being taken because documentation on the property had been misplaced. The core samples will tell engineers if the gas tanks were properly emptied prior to the selling of the property.

“This drilling has nothing to do with the city,” Bruce said.