The Government's proposed, contentious, changes to Schedule 4 in the Crown Minerals Act herald the most far-reaching legislative change to New Zealand's mining sector in decades. Is there $140 billion of inerals underground waiting to be plucked, or would the proposed changes damage a world-class tourism asset? Simon Hartley looks at what has come out of the ground in recent years.
Mining's value to New Zealand exceeded $2 billion for the first time in 2008, shrugging aside the onset of recession and fuelling a debate on the sector's potential to lead the way to economic recovery.
East Otago-based OceanaGold, and improving global spot gold prices, contributed hugely to the $2 billion record, providing the majority of a near doubling of gold production to $626 million during 2008.
Many mining sector companies were hit hard during the recession, as global demand for metals, barring gold, fell off historical highs, but now, Chinese and Indian demand is increasing again, underpinning a mining sector-led recovery in Australia.
The New Zealand Government's proposal to open up 7000ha of land protected under Schedule 4 in the Crown Minerals Act, which at present safeguards 13% of the country's land mass, including 14 national parks, is out for public consultation.
This closes on May 26 and more than 14,000 submissions have been received.
The Schedule 4 issues are obvious for both sides; the National-led Government wants an economic boost from opening up the land available for exploration, hoping the Mining Industry Association is correct in estimating mining's value to New Zealand can be doubled from $2 billion in 2008.
The critics, such as Forest and Bird and the Green Party, see any reallocation of Schedule 4 land as endangering the environment and putting at risk New Zealand's clean, green image and impacting negatively on tourism,which pulled in $6.1 billion last year.
The Schedule 4 issue will not go away in a hurry, following the initial "mineral stock-take" announced by Minister of Energy and Resources Gerry Brownlee at the Australian Institute of Mining and Metallurgy, New Zealand branch conference in Queenstown last August.
The areas immediately affected by the proposed removal from Schedule 4, and the minerals targeted, are coal in the upper South Island's Paparoa National Park, gold deposits in the Coromandel and silver and gold within some of the Te Ahumata Plateau on Great Barrier Island.
The South Island, and Otago in particular, continues to be one of the most prospective mineral regions in the country, with OceanaGold's exploration spend last year of $4.2 million accounting for 46% of the national total.
While Newmont's open pit Martha mine, near Waihi, and the relatively new Favona underground mine produce less annually than Oceana's 300,000oz, the open pit method has in the past 130 years produced more than 7.5 million ounces of gold.
Similarly, Heritage Gold's area of interest near Waihi is estimated to have yielded more than 4 million ounces of gold and silver from 35km of tunnels since 1875.
Otago attracts more than its fair share of exploration funding from Oceana, the fourth largest producer in Australia and New Zealand.
Much of Glass Earth Gold's exploration spending of $24 million since 2006 went to Otago.
The province grew and prospered on the back of a gold boom.
An Indian man from Bombay, Edward Peters, better known as Black Pete, discovered the first workable gold field in Otago in 1858, in the south branch of the Tokomairiro River.
However, his relative inexperience did not translate the opportunity into a gold rush; that was credited to Gabriel Read, who unearthed gold at Gabriel's Gully near Lawrence in 1861.
Many of Otago's present-day townships owe their foundation to serving the gold exploration sector at the time.
It has been estimated up to 12 million ounces - from both hard-rock trapped gold and loose alluvial gold in dry deltas and riverbeds - have been taken from Otago in the intervening 149 years.
In March this year, 20-year-old Oceana poured its 3-millionth ounce of hard-rock gold from its East Otago open pit and Frasers underground mine at Macraes, which is further boosted by open-pit mining operations at Reefton on the West Coast.
In May 1861, in a gully near Lawrence, Tasmanian-born Read, a veteran of the 1840s Californian and 1850s Victoria gold rushes, made his first discovery, prompting the gold rush to Central Otago.
The years 1861 to 1867 are credited to have uncovered 2 million ounces from Central Otago.
Read's discovery saw Otago's population grow from 12,000 to 30,000 people at its peak, of whom up to 10,000 went to Lawrence, searching for their own Gabriel's Gully.
Miners in Otago extracted more than 8 million ounces between 1860 and 1990; the bulk being 7.6 million ounces from alluvial, loose gold mining, and just 320,000 ounces from hard-rock crusher mining.
Immediately after Read's discovery, the gold rush spread to the Cromwell Gorge in mid-1862, then to the Arrow and Shotover Rivers.
Many of those old diggings remain of interest to small companies underpinned by record spot gold prices holding around $US1100 in recent months, which makes smaller claims commercially viable.
Hard-rock mining by OceanaGold has accounted for a further 3 million ounces to date, mainly from open-pit methods.
There are at present more than 150 prospecting and mining-related exploration permits covering Otago, including many multiple claims.
They range from single small-scale permits for individuals to Fulton Hogan's seven permits for aggregates to the 10 permits held by OceanaGold.
Sweeping, multiple-permit applications by Australian iron ore giant Fortescue Metals Group and New Zealand-based, Toronto-listed Glass Earth Gold in 2009, respectively for 29,000 sq km around the country and 1.3 million hectares in Otago alone, were criticised at the time.
The concern was large companies had "tied up" prospective areas.
Around New Zealand, mining concessions, both commercial and hobby but excluding coal, stand at 49 mining licences and 461 mining permits. There has been a surge of interest in hobby and small commercial permits since global gold prices rose.
While more than 2 million tonnes of metals were mined collectively in 2008 - gold (16.2t), silver (31t) and 2.02 million tonnes of ironsand - with the total accounting for $644 million of combined value, the non-metals sector extracted a combined 41.9 million tonnes, valued at $536.5 million.
Non-metals include the every-day additives used for bricks and tiles, roading gravel, limestone for agriculture and cement, and reclamations rocks.
New Zealand Mining Industry Association chief executive Doug Gordon is adamant mining can be the vehicle to deliver a "major" economic boost and tackle recession-led unemployment.
"Yes, there are significant cultural and social hurdles to go through. I would have thought it desirable for New Zealand to be energy efficient and environmentally responsible at the same time," Mr Gordon said.
He cites unemployment of 12% in areas of Northland where there have been estimates of $47 billion of minerals in the ground.
Based on that model, annual minerals production could be worth $296 million; a total $683 million in all-sectors output and per-head GDP would rise more than 270% - an extra 2720 jobs, Mr Gordon claimed.
Similarly, Southland and parts of South Otago have been identified as containing up to 15 billion tonnes of low-grade lignite, of which 8 billion tonnes could be mined and turned into diesel, fertiliser or energy, as could the methane gas associated with lignite deposits.
Mr Gordon acknowledges lignite is seen as "dirty" carbon-producing fossil fuel, but New Zealand should be "in the forefront" of creating a "world-leading centre for excellence" to study cleaner options for lignite use, again highlighting estimates that 200 jobs could be created in Southland to process lignite.
He said critics of mining should take roading aggregates as an example of what the sector produces, saying up to 11 tonnes per year of aggregates are produced for every person in the country.
"It's one thing to talk about creating wealth [such as gold] when digging up minerals, but health and welfare of the community is also an issue here," Mr Gordon said.
He set aside criticisms that mining profits go offshore to large international companies, saying it was a "xenophobic myth" and "anti-mining rhetoric".
He claimed for every $1 created by the sector, 75c stayed in the country in wages, royalties, tax, GST and reinvestment in exploration, processing and equipment, saying that of one company's recent $190 million revenue it was calculated 91% stayed in the country.
On claims land is "destroyed" and "scarred" by mining, Mr Gordon says modern mining methods include regulatory rehabilitative measures, plus own-industry standards.
"The public realise it is not acceptable for costs not to be met on environmental issues. They [environmental issues] can be dealt with up-front, by the RMA and Conservation Act, before a pick is even put in the ground," he said.
Setting aside an estimated $100 billion worth of southern lignite, consultant geologist Richard Barker has separately estimated there is $140 billion worth of minerals still in the ground - a figure disputed by critics but which Mr Gordon believes is "conservative".
He estimated that the mineral stake could potentially underpin 44,000 jobs and boost GDP by 3%.
Oceana employs 780 people and is expanding its exploration at both Macraes and Reefton, having recently pushed out its life-of-mine expectations to six years and boosted its exploration goals at both Macraes and Reefton by about $7 million.
Gold, and its highglobal price, regularly captures headlines, but so do concerns about the of scarring effects of large-scale open pits, tailings and dams.
The Government will decide on any changes to Schedule 4 in the third quarter of the year, but it's certain to be an election issue in 2011.
A visit to any of the major underground mines in the country, including Oceana Gold's Frasers tunnel, Newmont's Favona, Pike River Coal's tunnel into the Paparoa Ranges and Heritage Gold's exploration of the historical Karangahake diggings near Waihi, show they are literally just portals in a cliff-face.
However, it is the extent of the supporting roading, infrastructure, dams and waste ore piles that cannot be ignored.
The challenge ahead for the mining industry is to prove it can mitigate any environmental impact, to virtually zero, and fully restore landscapes.
