The wife and sister of missing prospector Michael Graham are driving home across the Nullarbor as searchers deploy five trail bikes and a third aircraft in the race to find the 46-year-old.
After more than a fortnight, police have narrowed the Goldfields search since Saturday after finding signs late last week of where he apparently sheltered for days at a windmill 15km from the search headquarters.
But trackers have found no fresh signs of the NSW tourist.
The use of the trail bikes puts in review a six-month Department of Fire and Emergency Services health and safety ban on volunteers using all-terrain vehicles.
Early in the search, a long-time volunteer said the ban meant much less ground could be covered and it would eventually cost a life.
The police decision to use trail bikes also raised eyebrows among prospectors who had offered to search. This help was rejected to avoid losing more people and so the search area would not be contaminated with extra tracks.
But on Saturday, the prospectors moved into the search area at Kurrajong with two cars, three quad bikes and enough fuel for 10 days.
That night an infra-red aerial search spotted the prospectors but police did not have the authority to order them to leave.
Searcher Steve Fisher said he contacted Mr Graham's family in NSW before moving in.
"There is frustration coming from everyone," he said. "The prospecting community is quite tight. If we were lost, we'd like someone to look for us."
Sgt Todd Pender said yesterday there was a good chance Mr Graham was alive and walking over the ironstone and mulga country.
The search, 140km north-west of Menzies, was to be scaled down on Wednesday until Riverina station owner Don North and grandson Nathan found an SOS hacked in the dirt.
Mr Graham also scratched an SOS on a road in waterless sandy country and indicated he would return to a windmill 10km to the west.
But his wife says she has lost hope he will be found.
Helen Graham and her sister-in-law Lisa Dodson say they now simply hoped whole remains would be found and they would not have to rely on DNA to identify him.
After almost two weeks in Menzies, they will leave uncertain about why Mr Graham left his mate at their bush camp during the night with the car boot open.