Large swaths of Otago and Southland have been pulled aside from mineral prospecting by Government permitting agency NZ Petroleum & Minerals for multimillion-dollar airborne aeromagnetic surveys.
This is the second time a large mass of Otago has undergone aeromagnetic surveying.
The latest two surveying areas surround the earlier block surveyed, which was about 13,000sq km.
NZ Petroleum & Minerals (NZPM) has set aside 23,000sq km comprising 15,748sq km in south and west Otago and Southland, 3711sq km in North Otago and 3749sq km in east Nelson and Marlborough.
''These surveys will gather high-quality, high-resolution data which can be used to attract minerals investment and build the understanding of New Zealand's geology,'' NZPM said.
While NZPM said prospecting permits for metallic minerals would not be granted or extended in any of the three southern areas, it does not affect any permit application received or granted before July 9, nor does it affect applications for mineral exploration or mining permits.
The Government has set aside $6 million over four years for aeromagnetic surveys.
NZPM senior communications adviser Britton Broun was contacted and said the tender for the surveying was open until tomorrow. The surveying would be a combination of helicopter and fixed-wing work, depending on the terrain.
Mr Broun said the surveying would be done over the coming two summers. This year, it was expected to begin in November and last for several months.
The findings will go into a NZPM database that international exploration companies can access, to encourage applications for exploration permits.
When asked why prospecting applications were being suspended, but not similar but more detailed on-ground exploration, Mr Broun said once the survey data was processed it would be available to companies.
''In these [three southern] areas we want companies to invest in exploration, which is a step closer to potential production than prospecting; hence the reservation only being for prospecting,'' Mr Broun said.
Aside from identifying minerals and aggregates, the aeromagnetic surveys provide useful information for scientists and councils on soil science and hazard, fault-line and aquifer identification, he said.
The former Glass Earth Gold (now Antipodes Gold Ltd, and subject of a reverse takeover) spent about $40million in exploration, largely around Otago, over six years until mid-2013.
As the country's largest explorer at the time, it included a $4million aeromagnetic survey covering more than 13,000sq km of northern Central Otago during 2007-08, to which the Otago Regional Council contributed $1million.
The boundaries of the new NZPM surveying areas roughly surround the perimeters of the earlier Glass Earth boundaries.
In the 2014 Budget the Government set aside $8million over four years for studies around the country, with about $6.4million for new aeromagnetic and specific geotechnical studies.
Combined with previous aerial surveys, the new surveys would lift coverage to about 30% of New Zealand's total land area. The most recent survey completed was in Northland and the West Coast.
