A Western Australian woman never thought her retirement dreams would sink quite so literally – or so quickly – until she found a 10-metre sinkhole had swallowed a chunk of her property days after she moved in.

“You should feel safe in your own home, and I don’t,” said Pia Ramsing.

In August last year, she was walking around her 2.3-hectare Collie Burn property, located about 200km south of Perth, when she discovered the giant hole in the ground.

“I thought, what the hell? This wasn’t here yesterday, this big hole in the paddock,” she told news.com.au.

“I had no idea where it came from or what it was. So I tried to look down and you could see the supportive beams down the bottom so I thought it must have been a mine shaft.”

Her suspicions were correct: her new property was indeed built on top of a mine. It was an abandoned mine from 1903 — a fact that, Ramsing alleged, was never disclosed before she bought the lot in July 2022.

Pia Ramsing. Photo / Supplied

In the months since, she has contacted the local council, Collie and Perth mining departments, even local mining companies in an effort to solve the subsidence. But, she said, she had largely been “fobbed off”.

Ramsing thought she had made some headway with the state Department for Mines, Industry Regulation and Safety’s (DMIRS) Abandoned Mines Program, established to help rehabilitate or secure former mining sites.

But that quickly sank, too, because of the location and depth of the sinkhole.

“They basically said they didn’t know how to tackle it because it’s a private property and shallow mines,” Ramsing said.

“DMIRS pretty much told me in August that they didn’t have any money in the department to cover me or cover rehabilitation.”

However, in March, the department sent a geotechnical expert to inspect the Bacon St property.

The officer found there was potential for further subsidence on the land, reporting small depressions, cracking, water drainings, and water pooling on the lot.

A map provided to Ramsing after the inspection shows the southern portion of her lot contains “known underground working areas”. It also shows three additional “record(s) of subsidence” across the road.

The department reportedly told Ramsing it was up to her to backfill this and any future sinkholes, but warned against using heavy machinery on top of the abandoned mine shafts.

The map provided by DMIRS, the sinkhole is circled red. Photo / Supplied

This was despite the real estate agency’s description of the “rare earth” lot claiming the acreage would be “ideal to use as a weekender camping base with lots of room for heavy vehicle parking”.

“I will gradually fill up the hole and hope I don’t have any more. But it’s hanging over me there’s another spot on the property where ground is sinking in,” Ramsing said.

“I’ve invited the community if they have any leftover gravel or concrete to come and fill up the hole.”

She said even the local mining company had said it was happy to provide fill, but she wanted to do it “the right way”.

“I don’t want to just put something down and it wash away and have to refill it all the time. That’s why I thought DMIRS would know that, really, it’s their responsibility.”

Council has added to Ramsing’s frustrations, when it denied her plans to build a tiny home inside an existing shed on the property. The shed was reportedly constructed without council approval by the previous owner and is within the mine zone.

“I’m living in a truck I’ve converted into a mobile home in a space away from the mine,” she said.

“I thought this would be the perfect property with plenty of riding space for my horses. I want my vegetable garden, my fruit garden, and I don’t want to fear the land caving in.

“You should feel safe in your own home, and I don’t.”

In a statement provided to the ABC, the DMIRS said it was up to property buyers to “conduct due diligence” to check for abandoned mines if they are moving to a town with a mining history, like Collie Burn.

“There are publicly available maps and plans that show the location of abandoned mine features,” DMIRS said.

“DMIRS continues to provide advice to Ramsing regarding the sinkhole.”

It said the state would not be able to “remediate all abandoned mine features”, but Ramsing said in Collie alone there were four sinkholes across Bacon St.

“Are they not scared that something is going to happen? Even to traffic on the road, school buses with children, are they not worried what might happen?” she said.

It is understood Collie Shire Council has engaged the state’s roads department to conduct a survey of the road and assess the potential for further subsidence.

A copy of a council email seen by news.com.au on Friday confirmed engineers “engaged by DMIRS” intended to view Ramsing’s property again at the start of April.