Beaumont children: Mystery find at Castalloy dig site at North Plympton solved

Experts have weighed in on the detection of a suspicious hole on the fifth day of a dig in the search of the Beaumont children.

Excitement quickly turned to disappointment at the Beaumont children’s dig site on Thursday, where the excavation team believed they had found a 2m pit of a “similar size” to a grave, filled with mixed coloured sand.

Forensic archaeologist Professor Maciej Henneberg, an expert overseeing the dig at the former Castalloy factory, on Thursday afternoon told reporters his team had made the discovery the same day.

He said he found a “2m long, 2m deep pit of mixed colour sand and a little bit of organic material” that was a “similar size” to the grave the team was trying to locate, and the mixed colours suggested someone had dug the hole and refilled it.

Forensic archaeologist Professor Maciej Henneberg, left, with author Stuart Mullins and retired major crime detective Bill Hayes and MP Frank Pangallo. Picture: Russell Millard Photography

But despite the team’s high hopes, later on Thursday Prof Henneberg had already ruled out the hole’s significance.

A spokesman for Frank Pangallo MLC said that on further investigation, the professor believed the soil colour changes were caused by the installation of a stormwater pipe.

The hole had been found at the site of the original 2013 search but was in a deeper, unexplored area.

Professor Maciej Henneberg, in yellow hi-vis, at the site being excavated. Picture: NewsWire / Brenton Edwards

Excavations have been continuing this week at the old factory in a last-ditch bid to find the children Jane, Arnna and Grant Beaumont, who vanished in 1966.

In 2013, two men came forward claiming Harry Phipps, a businessman, had paid them to dig a hole resembling a grave at the old Castalloy factory just three days after the children’s disappearance.

The claim motivated Mr Pangallo to organise the dig this year to locate the grave, before the site is sold to developers.

He said the 2025 excavations have been far deeper and more expansive than previous digs at the same site in 2013 and 2018, reaching to a depth of 4m.

“Hope isn’t going to fade,” he said on Thursday. “I’m never going to stop giving up while we’re here.”

On Wednesday, SA celebrity Andrew Costello vowed to fund a new search on the Yorke Peninsula at Stansbury, after learning about a long-circulated theory about the whereabouts of the children’s remains.

“Bless Cosi, well done mate, for wanting to have a go,” Mr Pangallo said. “I encourage him to keep going.”

Originally published as Beaumont children: Mystery find at Castalloy dig site at North Plympton solved