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Published: 2011-08-12 00:00:00

An Auckland-based company has been awarded the contract for the final phase of work to remediate the country’s most contaminated site, the Tui mine at Mount Te Aroha.

Waikato Regional Council’s river and catchment services group manager Scott Fowlds said Hiway Environmental Ltd had proven ability and capacity to complete the contract and the price was within the contract estimated budget.

Detailed planning and preparation is underway, with the aim of starting the on-site construction of the two-staged final phase in October. This work will involve stabilisation and remediation of the tailings impoundment area.

Mr Fowlds described this next phase of the project as the most significant.

"The waste rock and ore (tailings) from the old mine site will be shaped into a stable landform, drained and capped to secure the site,” Mr Fowlds said.

The tailings dam is 25 metres high and includes around 110,000 cubic metres of waste material, which will be treated with lime.

“In the latter part of phase two the former tailings area will be landscaped, replanted and converted into a useable space for the community,” he said.

The Tui mine, on the western slopes of Mount Te Aroha, produced base metals including copper, lead and zinc over seven years before being abandoned in 1973.

Since then the mine and tailings dam have continued to leach heavy metal contaminants into the nearby Tui and Tunakahoia streams, which flow into the Waihou River and downstream into the Firth of Thames.

Waikato Regional Council has been working in partnership with the Ministry for the Environment, Department of Conservation, Matamata-Piako District Council and iwi since 2007 to remediate the site and improve the area’s water and soil quality.

The works aim to mitigate the present risks to community safety and health, and environmental damage to the mountain, streams and rivers.

The $5.5 million first phase of the remediation project is due to be completed in December. This phase has involved detailed investigations, designs and consents, and the underground treatment of polluted mine tunnels and surrounds.

Phase two of the project is projected to cost $16.2 million. This is to be funded by the Ministry for the Environment ($15.2 million), Waikato Regional Council ($800,000 in cash), and Matamata-Piako District Council ($200,000).

Further information is available at View a copy of the Minister for the Environment’s press release on funding arrangements here: