A plan to explore what was left of New Zealand's most famous mother lode has sparked renewed protests from a group of residents who live near Waihi's Martha open cast gold mine.
Instead of the mine's scheduled closure in 2017, the residents face the prospect of an unspecified number of additional years of mining to extract the last ore.
They are fighting Newmont Gold's application to vary its mining licence so it can drive a 2.6km long exploratory tunnel down to 20 metres below the bottom of the open cast mine.
The company's quest for the "remnant" Martha vein has ended up in the Environment Court after residents and Ngati Hako iwi appealed the decision by the Hauraki District Council to allow the exploration.
If the tunnel confirmed preliminary results from surface drilling, then Newmont would seek to create a new underground mine extending across the width of nearly the whole rim of the Martha Mine, running from east to west.
Newmont has been forced into underground mining to recover the rest of the ore because open cast mining has nearly reached the limits of the site.
Opening the case for Newmont yesterday, lawyer Rob Fisher said the exploration would take two years and involve driving a 5m wide by 5m high tunnel to a depth of 280m below the pit rim.
As well as tapping into the remnant Martha vein, the miners would also drive into previously unmined rock within the Ella lode on the western end of the pit.
Mr Fisher said Newmont wants to remove the restriction on underground mining that limited the company to going no deeper than 100m below sea level.
Its target depth of 20m below the existing pit floor was 140m below sea level.
It also wants to extend the operating hours so that underground mining can take place 24 hours a day, seven days a week, and for underground blasting to be allowed for an extended period of 7am to 7pm Monday to Friday and from noon to 7pm on Saturdays.
The key environmental concerns of objectors were the noise and vibration generated by the exploration and the alleged damage to properties from mining. Other issues were the social effects on the community and the cultural impact of mining.
Mr Fisher refuted objectors claims that mining had damaged their properties.
"No evidence has been provided that demonstrates that the damage to property is due to Newmont's activities."
He said the evidence of Newmont and the Hauraki District Council was that the vibrations from blasting were well below the levels shown to cause damage.
Other issues raised by objectors such as dust, dewatering and the effect on property values went beyond the scope of the Environment Court's jurisdiction, he said.
Mr Fisher said that no changes were proposed to the noise and vibration limits already imposed by the existing mining licence.
The appellants were Waihi residents Colin and Sylvia Francis and Collette Spalding, Green MP Catherine Delahunty and Te Kupenga o Ngati Hako represented by Pauline Clarkin.
Ms Spalding's evidence will be supported by eight witnesses.
The hearing was expected to last most of the week.