Photo: Wikicommons

Foulden Maar, a 23-million-year-old crater lake near Middlemarch, isn’t exactly a hot spot.

“It’s quite popular with academics from the University of Otago,” says Tim Miller, who reports for the Otago Daily Times.

“It’s on a farm, so it’s very inconspicuous if you were driving past you'd really have to look to see.”

However, while not a tourist trap, the maar is significant in a scientific sense because it contains a large collection of well-preserved fossils. It also contains diatomite – a type of rock which can be broken down and used in fertilisers or, as Australian company Plaman Resources intends, animal feed.

Last year, Plaman Resources – based in Australia but largely Malaysian owned – obtained a $30 million loan from investment bank Goldman Sachs to mine 500,000 tonnes of diatomite a year at the site. It already owns land near Foulden Maar, but to mine economically, it needs to purchase a neighbouring property too.

Almost a year and a half ago, it applied to the Overseas Investment Office for permission to buy the land. But the application met immediate opposition, first from neighbours worried about road noise and dust, and then from palaeontologists worried for the loss of the valuable fossils of Foulden Maar.

“To be commercially viable, the mine would have to be fully extracted, that would leave none of the maar left. Obviously, that’s a lot of scientific research that would be gone, so scientists and geologists jumped in and said 'we need to protect this site', says Miller.

The opposition galvanised in the wake of a leaked Goldman Sachs report, which was written for investors but ended up in the hands of the Otago Daily Times.

“It talks about the amount of diatomite that they want to extract, which is 30-million tonnes… which needs to be trucked. There are plans to build a processing plant near Milton, which is over 100 kilometres away from the mine itself,” says Miller.

Dunedin’s mayor, Dave Cull, says the information in the leaked report contradicts the assurances he has had from the company.

“He’s worried specifically about the claims that local opposition to the mine would be too under-resourced and small to fight any environment court case. He’s also worried about the quality of the diatomite there, and access for the scientific community to that very important site,” says Miller.

Mr Cull is now awaiting a response from Plaman Resources to his concerns. However, the ball is now sitting with the Overseas Investment Office, which is deciding whether to approve the land purchase required to get the mine going.

“Even if that is approved, there will be a need for resource consent from the councils here. The local people have said they will go as far as they need to, to oppose this mine.”