Seabed mining could be under way off Taranaki's coast in five years or less, according to a company prospecting for mineral deposits.
Trans-Tasman Resources was the first of four companies granted prospecting licences both onshore and offshore around Taranaki by Crown Minerals since last March.
Trans-Tasman's prospecting permit is set to expire in March next year, and executive chairman Bill Bisset said the results had left the company optimistic about the resource.
Mr Bisset said the next step would be to apply for an exploration permit. All going well, the company was looking to begin mining in four to five years.
Iron Ore New Zealand has an exploration permit application pending along with global mining heavyweight Rio Tinto. Iron Ore director John Rutherford said his company was keen to move past the prospecting and exploration stage and begin mining.
Trans-Tasman has taken about 165 surface and core samples from within its prospecting sites.
On the coast between Opunake to south of Wanganui, the results "suggest the existence of a potentially very large resource", according to Trans-Tasman's website.
The average concentration of iron sands over the whole area surveyed was 8.3 per cent, well above the 6 per cent required to be commercially viable.
In some places the iron sand concentration is between 15 and 40 per cent.
"What we're talking about is the development of something of global proportions and the potential of it is significant," Mr Bisset said.
He said the company was acutely aware of concerns over seabed mining and was making every effort to be open and address those as they assessed the overall viability of the project.
"A lot of what's done in the prospecting stage is not just geological work but all the other stuff as well.
"Environmental and social issues need to be covered off because if they're not it doesn't matter if there's seams of gold or diamonds down there, it's not going to happen," Mr Bisset said.
But those concerns had to be balanced against the potential financial benefits to the region both in revenue and job creation, he said.
The company had encountered plenty of excitement about the opportunities, especially in employment.
Trans-Tasman is proposing to dredge sand off the ocean floor and transport it to an offshore rig station which will extract, de-water, wash and store the iron ore.
The company's preferred option is to then ship it from the offshore station to an onshore steel plant in New Zealand, or to Asian markets.
The rest of the sand and waste would be put back on the ocean floor.
The company's website says that with concentrations of iron sand of 10 per cent, an area of 20km by 20km would sustain a 10-year mining operation.
Over that time, it estimates 5 metres of sediment would be removed from the sea floor, but 4.5m of it would be returned, leaving a total impact to the sea floor of just 50cm.
In 2008, the parliamentary local government and environment committee released a report in response to a petition organised by protest group Kiwis Against Seabed Mining and signed by 15,113 other people calling for a government ban on seabed mining.
The committee's report concluded that a blanket ban on seabed mining was unjustified and said: "Mining should be undertaken with appropriate environmental safeguards and further research into the environmental impacts of seabed mining is needed."
In preparing the report, the committee heard evidence from KASM, Crown Minerals, and the Conservation Department.
Crown Minerals admitted the use of dredge mining would have an environmental impact, including clouding of water caused by fine sediments, and spread of sediment containing toxic material.
That would affect species living in and on dredged material but Crown Minerals suggested storms had a similar effect.
- Taranaki Daily News