Foulden Marr, near Middlemarch. Photo: Gregor Richardson

A University of Otago paleontologist has broken her silence on a controversial mining proposal, saying she was "more than horrified'' to learn the full extent of plans for Foulden Maar, near Middlemarch.

Associate Prof Daphne Lee spoke to Dunedin City councillors at a public forum yesterday afternoon, criticising the proposal to mine hundreds of thousands of tonnes of fossil-rich diatomite at the 23-million-year-old site to add to animal feed.

Her understanding from reading research papers, and from conducting her own chemical analysis, was the black diatomite in the mine had no more benefits than the dry, white diatomite which was usually mined.

"I'm pretty sure that there is nothing in it that is different to ordinary white diatomite.''

Prof Lee described the maar site as "absolutely amazing'' and "totally globally significant'' - and said if the mine went ahead, she would feel her entire scientific career was compromised.

Daphne Lee

She had been reluctant to express a strong opinion due to concerns scientists might not be allowed further site access.

When asked by Mayor Dave Cull whether commercial exploitation of the area was compatible with optimal scientific research, Prof Lee said "not at all''.

The previous mining company was working on a very small scale, she said.

When asked to speak to the Overseas Investment Office about mining plans there about a year ago she did not realise the full extent of the proposal, and was "more than horrified'' to read about it in the media.

Plaman Resources New Zealand general manager Craig Pilcher has previously told the Otago Daily Times the diatomite in the mine, which is trademarked as Black Pearl, was of a high quality and suitable as a high-value feed additive.

Ideally the Foulden Maar site would be Government-owned, Prof Lee told the forum.

Researchers have uncovered hundreds of new species of flora and fauna, in a site about the size of a tennis court - and in terms of scientific research there was a huge amount still to uncover.

Plaman Resources intends to mine 500,000 tonnes of diatomite a year from the 800m by 1000m site, for about 27 years.

Dunedin city councillors had been expected to debate a notice of motion, from Cr Aaron Hawkins, seeking council recognition for the area's fossil record, and support for its protection as a scientific resource.

However, yesterday's council meeting adjourned part-way through, after 6pm yesterday, before reaching the item.

The meeting resumes at 9am today.

elena.mcphee@odt.co.nz