Philippa Stevenson: It's time for Te Aroha to be rid of toxic site

Could New Zealand's second most contaminated site, Te Aroha's Tui Mine, be next in line for a clean-up?

Logic suggests so, now that rehabilitation work is under way on the No 1 blot on the landscape, the former Fruitgrowers Chemical Company (FCC) site at Mapua, near Nelson.

You could excuse the people of Te Aroha - who are working hard to re-invent the town's Edwardian spa glory days - for wondering if the day is about to come when they can quit their toxic headache. They've only been waiting 32 years.

The FCC packed up in 1988, leaving behind what is known as an orphan site. In Te Aroha, Norpac Mining had done the same 15 years earlier.

Between 1966 and its receivership in 1973, Norpac mined 43,500 tonnes of copper, lead, zinc, silver and gold ore a year from the Tui mine on the western slopes of Mt Te Aroha.

It left behind 100,000cu m of dammed sludge and seeping mine workings that polluted the Tui and Tunakohoia streams, which feed the Waihou River.

The contamination forced Te Aroha to find a new water source and, in the 1980s, reluctant ratepayers had to pay to stabilise the waste heap.

The Matamata-Piako District Council owns the land housing the mine process plant and tailing dams, the Department of Conservation (DoC) has the site of the mine workings. In August 2003, I reprised the long history of Tui and its hoped-for clean-up, the reports on remediation options of 1998, 1999, 2000 and 2002.

I noted then that in January that year a weather bomb had struck Te Aroha, gouging out a gully downstream of the waste dam that had afforded the dam some protection.

The storm had made things just that bit more precarious.

Two years on the gradual deterioration of the dam continues. Maintenance work is needed in gullies where the acid leachate has rotted the casing of protective rock-filled metal baskets.

The greater risk is that an earthquake or major flood - neither rare in New Zealand - might shatter the worsening stability of the dam and bring it crashing down.

One of the brighter hopes for solving the clean-up dilemma emerged last December when Newmont Waihi Gold, the company mining Waihi's Martha Mine and about to open nearby a new underground mine, Favona, offered to dispose of the Tui tailings in Favona.

It's a good option because it means far less ongoing maintenance back over the hill at Te Aroha than alternate on-site rehabilitation.

But it comes at a high upfront cost of more than $12 million.

Now, another report.

In April, a workshop of all the parties with an interest in Tui - the Environment and Economic Development Ministries, DoC, the Department of the Prime Minister and Cabinet, Environment Waikato, the district council and Newmont - reviewed all the remediation options with the help of technical experts. Its first preference was for a new tailings dam to be built on the present site and for the mine tunnels to be dammed at a cost of more than $6 million.

An expanded version of the first option, which includes returning the finer tailings to the old tunnels, came in second favourite at more than $8 million.

The Newmont/Favona option was third solely on its price tag.

Who pays is, of course, the big question when it comes to orphan sites.

Legal opinions obtained by the regional and district councils say they cannot be held liable but note the Government's long history with the site.

The minerals were owned by the Government, which issued a licence to extract them and on which it received a royalty. The Government was also the only agency able to police the mining.

Sadly, though, it never sought a rehabilitation bond.

Early investigations into Tui were largely funded by companies involved in the mining industry and the two councils.

In 2000, Environment Minister Marian Hobbs visited the old mine and soon after that her ministry funded further study.

Late last month, the regional and district councils once again moved to put the matter back on the Government's agenda by backing the technical workshop's preferred, $6 million clean-up option and resolving once again to send the bill to Wellington.

Dennis Crequer, Environment Waikato manager of special projects, said it was hoped the council's latest reminder would get some action before Government departments were hit by pre-election paralysis.

For a town poised to build anew on a historic reputation for its restorative mineral waters, it is past time it received help in getting rid of an unwanted legacy.

More than three decades is long enough to get to number two on our toxic hit parade.