Chatham Rock Phosphate, the small Golden Bay-based company with big seabed mining ideas, has submitted its formal marine consent application to vacuum up phosphate nodules from the Chatham Rise.
With a plan that the seafood industry warns could have a dramatic effect on deepwater fishing, the company intends to use a giant Dutch ship to suck up the phosphate and supply it to the fertiliser industry.
The company says the application represents four years' work and $25 million in investment, and that if it is approved mining could begin in 2017.
But Deepwater Group chief executive George Clement says there is a large and inherent risk of massive disruption to the seafloor, the benthic biodiversity and seafood ecology if it goes ahead.
Once the Environmental Protection Authority accepts the application as complete, a six-month formal process will begin, including the gathering of written submissions and a hearing before an EPA board.
CRP corporate affairs director Linda Sanders said its application would cost an estimated $4m, some of which would come from capital raising associated with a pending listing on the London Stock Exchange, planned for July.
The marine consent is the only major licence CRP now needs, having gained a mining permit for the phosphate extraction project in December 2013.
Managing director Chris Castle said he was confident the application would meet the tough standard demanded by the law.
"Our focus has always been two-fold: Base the analysis on science and consult with all interested parties to ensure their concerns are addressed through the process. The results of this analysis and consultation are that we understand what the environmental impacts are likely to be and we can clearly demonstrate how we can minimise and mitigate them," he said.
"We know this project can deliver to its shareholders financially, and to other stakeholders in terms of environmental requirements."
He said the phosphate resource, located on the seabed 250 kilometres from the Chatham Islands and 400km from the Canterbury coast, offered fertiliser security for New Zealand's primary industry, big export and import substitution potential, and environmental benefits as a direct application fertiliser, making it a project of national significance.
The New Zealand-listed company, part-owned by Dutch dredging and shipping giant Royal Boskalis and American venture capitalists, intends to hoover up sand, silt and phosphate nodules from gravel to tennis-ball sized lumps for sale, unprocessed, to the fertiliser market in New Zealand and overseas. It believes the resource is worth $6 billion, and has forecast earnings of $62m to $100m a year for 15 years.
The production area covers 820 square kilometres of seabed up to 400 metres underwater, deeper than any previous seabed mining.
Clement said the seafood industry wanted the EPA to defer the application until legal anomalies around New Zealand's benthic protected areas were resolved.
It was unacceptable that the seabed in this area could be mined when it was illegal for a fishing net to touch it or even go within 50 metres.
"It's a case of different rules for different users. In the interests of conservation, the untouched biodiversity that exists on the seabed of the BPAs should neither be trawled nor mined."
Sanders said CRP had been talking to the Deepwater Group and other interested parties.
"We're going to be affecting 30 square kilometres a year, and they affect 50,000 square kilometres a year. We think our impact is going to be very minor."
Benthic Protection Areas were introduced in 2007 and cover a third of all of New Zealand's Exclusive Economic Zone. They were designed to protect representative and untouched ocean biodiversity from proximity of fishing gear to the seafloor.
CRP has a Wellington office but Castle and Sanders live in Golden Bay, from where they also operate their interests in other mining development ventures.