Deadly mineral erionite could complicate the Waitematā tunnel project

By RNZ’s Phil Pennington

A $ 7.7 million search is underway for a deadly mineral beneath Auckland, but has already encountered objections from the city’s train tunnellers.

Cancer-causing erionite is worse than asbestos, but less common.

It could complicate major construction projects, including drilling a new tunnel under the port of Waitematā if that continues.

The Transportation Agency just completed a business case for another port crossing and said a tunnel was “the most likely option.”

Erionite can and has killed people by causing mesothelioma, a cancer most easily associated with asbestos.

Auckland is one of the few places in the world that has the rare mineral underneath, in rocks called Waitematā Group sediments that are widespread.

Research to identify exactly where it is, assess exposure risk, and conduct tests and standards to address erionite, has earned $ 7.7 million in support of the Endeavor Fund. It is led by Jenny Salmond, Associate Professor at the University of Auckland.

“We know erionite is a carcinogen, we know it’s here,” Salmond said.

“The question is, is it escaping from the rocks?

“If it is contained within the rock, it is not a problem. But if it enters the ground and then into the air, or goes directly from the rock to the air, then it is a problem.”

The potential threat is twofold: from dust, such as drilling and tunneling, and what is done with waste dirt afterward, such as the massive amounts that came out of the Waterview tunnel previously or the City Rail Link project now.

Unhappy Crown Entity

CRL said research to date suggested a “very low” probability of erionite in the 3.45 km rail corridor, and it had not been found so far, in hundreds of test holes.

The Crown entity was upset by researchers’ early warnings that emerged at an erionite briefing with the Auckland Council last November.

“City Rail Link Ltd and others challenged some of the language used in the Erionite Research Group draft briefing document,” CRL told RNZ in a statement.

“It was felt that the language used could give the impression that the safety and health impacts of construction work were not being adequately managed for workers or the public.

“This perception is incorrect and the group’s published article addressed our comments.”

That article, in a journal of the Medical Association in July, said that the scale of the earthworks meant that it was urgent to quantify the potential for “significant exposure” of Auckland residents to erionite dust if dust management strategies they were not carefully implemented.

CRL “did not threaten or consider legal action with respect to the erionite report,” City Rail Link said, adding that it was collaborating with investigators.

Additional well samples were being analyzed for erionite abroad, as this country lacked the necessary laboratories, and the data was shared, he said.

Salmond said the collaboration was strong.

Industry “will help us direct our research to help them. And our research will direct their activities.”

“As with any emerging risk, how we handle it is challenging,” he said.

Exposure to erionite has been fatal – it caused about half of all deaths in three villages in Cappadocia, Turkey, until the alarm went off several decades ago. They had inadvertently used erionite to build houses.

An early warning on the mineral was issued in New Zealand in 2011, in a geologist’s report to the Environment Court.

“It seems prudent … to consider what danger erionite deposits might pose to the people of Auckland and to introduce precautionary measures in resource consents to minimize any potential health hazards,” the presentation read.

Nothing came out, although asbestos researchers mentioned it in 2015.

New Zealand has a high rate of mesothelioma, but no one knows exactly why.

The Auckland Council said its geologists doubted there was erionite underneath the central city and were collaborating with researchers.

“We have already taken steps to ensure that we are prepared to manage any risks that may arise … especially at key construction sites,” said the council’s chief compliance officer, Steve Pearce.

Currently, CRL was the only project of interest, and the only one with consented resources that specifically mentioned erionite, but all earthworks required protocols for the discovery of unexpected contaminants, Pearce said.

The air quality monitoring at the Aotea and Mt Eden stations of the rail project was updated in March to include erionite and is reviewed independently.

However, it is unclear if the tunnel waste is being analyzed for the ore or how it is being analyzed; RNZ is trying to clarify that, and whether the waste is currently treated as clean landfill.

“Only natural soils or rocks where soil contaminants are absent can be disposed of in clean landfill disposal facilities,” Pearce said.

Implication for the port tunnel

The concern was not limited to major projects, said another of the researchers, associate professor of geology Martin Brook.

“Brand new residential development, if the erionite is in rocks or soils near the surface, that could be a problem,” Brook said.

A major tunnel construction project ahead could be a port crossing.

The Transportation Agency said its business case for Additional Waitematā Port Connections (AWHC) had already been completed.

This is part of a more than $ 100 million investigation into what to do to ease Auckland’s congestion.

The business case “builds on previous work exploring the feasibility of a tunnel crossing, and although this remains the most likely option, further planning is still required to investigate the need, timing, function and form of an additional crossover before making a final decision, “the agency told RNZ in a statement yesterday.

Any tunnel was more than a decade away, it said.

The developers of any tunnels through the harbor should watch out for zeolite or sandstone rocks, Brook said.

“Some of that zeolite should be analyzed for erionite,” he said.

“It’s just a matter of dealing with it.

“Normally it would be disposed of as clean fill, but if it contains erionite it should probably be classified as contaminated fill.”

Professor Salmond said the researchers would collaborate with industry, medical and social scientists here and abroad, and that Italy in particular would provide useful experience.

“We are trying to prevent erionite from being inadvertently altered – that is the whole point of this research, to make sure we are not too late,” he said.

Work was also underway to establish international exposure limits for erionite for workplaces, as there are for asbestos, Salmond said.

The country’s regulator, WorkSafe, said it was awaiting the findings of the investigation.

“Companies that may be concerned should have a dust management plan in place,” he said.

City Rail Link said it was reducing the overall risk of dust by:

• Using a TBM with a sealed cutting head, which produces waste that is sludge (road head machines can be used to tunnel but generate much more dust).

• Dust absorption, maintenance of exclusion zones and monitoring; using personal protective equipment.

• Transport of covered and moistened waste; analyzing the offal before transporting it.

“The scale of CRL gives the project a great opportunity to provide more data on erionite and share that information with research groups and the general construction industry,” said CRL.

The air quality management regime would be reviewed and updated if erionite was found, he said.