Police will drain a dam on the remote outback farm where four-year-old Gus Lamont vanished a month ago, in a desperate attempt to find the little boy.

The latest step comes a fortnight after South Australian police wrapped up their most recent attempts to find Gus, who vanished from the property on September 27.

Friday’s search will involve draining a large dam about 600 metres from Gus’s family’s remote Oak Park Station homestead. It is about 4.5 metres deep and has already been searched by police divers in the first days of searching for the little boy.

“The draining of the dam will enable a comprehensive visual search to be completed, particularly areas with underwater vegetation,” SA Police said on Thursday.

“The renewed search of the dam is being undertaken to rule out the possibility Gus may have drowned.”

Gus was last seen at the station homestead, about 300 kilometres north of Adelaide, by his grandmother at 5pm on September 27.

Despite one of the largest searches SA Police has ever undertaken – involving dozens of officers, the Australian Defence Force, SES volunteers, trackers and local property owners – there has been no sign of him since. The original search, which also involved mounted and aerial resources, covered an estimated 470 square kilometres.

Police will drain a dam that divers have already searched. Photo: SA Police

Police said on Thursday that investigators from the taskforce set up to find the missing boy had also assessed data from a recent drone search.

“Unfortunately, the imagery has not identified any object of significance that has assisted in the search for Gus,” they said.

“Further aerial imaging of an area out to 10 kilometres from the homestead is still being conducted. This is being done in stages and will take several weeks to complete.”

The most recent search extended to 5.5 kilometres from the homestead, equating to 95 square kilometres searched on foot.

Police said the task force was following multiple lines of inquiry to locate Gus.

“These investigations have not uncovered any evidence of foul play,” they said.

Gus’s family is cooperating with police and has the support of a victim contact officer.