Police resumed investigations into the disappearance of Trisha Graf. Picture: NewsWire Handout via SA Police

Investigators searching for missing mother Trisha Graf have revealed a bleak turn in their approach, with hundreds of mineshafts set to be combed through.

Ms Graf, 41, was last seen two weeks before Christmas in the remote South Australian town of Andamooka, shortly after she had hit a kangaroo in her car.

Her disappearance has sparked widespread searches, with police returning to the Andamooka area on several occasions since.

On Monday, investigators again returned to the area in the hope of unearthing clues as to just what happened to her.

They say as part of the latest phase of the operation, about 1000 mineshafts in the immediate area will be searched.

Trisha Graf went missing before Christmas. Picture: Supplied

And Blue Dam, close to where her car was discovered, will be drained for the second time.

Previously, police drained the dam, which divers searched.

However, while they found nothing conclusive, they were also unable to eliminate the presence of any evidence of her disappearance.

Ms Graf was last seen in the early hours of Friday, December 12, driving along Dunstan Drive in Andamooka.

The previous evening, she had visited a Roxby Downs hotel, leaving at 12.19am on December 12, driving a white 2012 Ford Territory with registration S254BCX.

Searches for Ms Graf have resumed. Picture: NewsWire Handout via SA Police

She continued towards Andamooka before colliding with a kangaroo close to the township.

Ms Graf and her fried then carried on towards Andamooka, where they visited a home in the town’s northwest.

Ms Graf was last seen shortly after 2am, with her partner and a friend discovering her car perched on a dirt mount near the Blue Dam.

Since her disappearance, police have returned to the area several times, performing ground and aerial searches, without success.

Her car was found near a dam.

Anyone with information about Ms Graf’s whereabouts or her movements leading up to her disappearance is urged to contact Crime Stoppers online at www.crimestopperssa.com.au or on 1800 333 000. You can remain anonymous.

SOURCE: https://au.news.yahoo.com/search-mum-outback-takes-bleak-045127258.html