Excavation at a factory site in Adelaide has been called off after failing to find the remains of the missing Beaumont children, ensuring the 50-year mystery of their disappearance will continue.

The dig on Friday uncovered some animal bones but nothing related to the Beaumont children, Detective Superintendent Des Bray said.

Nothing related to the Beaumont children was uncovered by Friday's excavation. Credit:ROY VANDERVEGT

"I can confirm that we have searched the areas of interest and reached the bottom of those areas and gone well below so that we can be 100 per cent certain," Superintendent Bray told reporters.

"I can confirm we have found bones of various animals, but there has been nothing human located on the site.