Daryl Floyd is organising a fund-raiser on the Border to help bankroll the project, which is expected to cost from $30,000 to $50,000.

Terry James Floyd vanished from the intersection of the Sunraysia and Pyrenees highways, near Avoca, aged 12, on June 28, 1975.

A 2001 coronial inquest found he had likely died.

Victoria Police homicide detectives have investigated at least two suspects but have not laid any charges.

Mr Floyd has analysed evidence from the inquest and police investigation to identify a mine shaft near Avoca he believes may have been used to dispose of Terry’s body.

The 44-year-old, who was 10 at the time of Terry’s disappearance, said he had been advised police could not fund the excavation and has set aside $5000 of his personal finances to start the project this month.

The excavation team has costed the venture, approved by the Victorian Department of Sustainability and Environment, at $1500 per metre.

The crew expects to dig 20 metres to 30 metres below the surface as they search for clues.

“Hopefully through this, if something is found here — there might be some DNA still attached to Terry’s clothing, or if remains are found — there could be something that leads to a conviction,” Mr Floyd said.

But Mr Floyd, whose parents have since died, said regardless of the result, the excavation would bring “closure” to his suspicions regarding the mine shaft.

“I’ve ... been asked ‘what if nothing comes of this?’,” he said.

“But it’s part of how we can put a closure to this area of investigation.

“If it brings a negative result, you close that chapter and put it behind you.”

Mr Floyd said he had arranged for homicide squad veteran Detective Sen-Sgt Ron Iddles to present a talk in Albury-Wodonga on his experiences investigating crime, with proceeds to go towards the excavation project.

The event at the Commercial Club in Albury will be held on October 22. Booking details are yet to be finalised.