In another success story for MMP, Green MP Catherine Delahunty today announced a joint initiative with the National Party to clean up New Zealand’s most toxic site — Te Aroha’s Tui Mine.
The abandoned, environment-polluting mine has long been known as an issue, and decades later something is finally being done about it.
Environment Waikato wrote the following background notes:
Tui Mine’s story started in 1967. Norpac Mining Ltd opened it to extract metals, including copper, lead and zinc. The mine prospered and the company also found several thousand ounces of gold and silver among the ore. Then unacceptable levels of mercury were found in the ore and the mine became uneconomic. In 1975, Norpac went into liquidation and Tui Mine was abandoned.
Mining equipment was removed for use at other sites or sold for scrap. Left behind was a large pile of ore and sand-sized crushed ore (tailings), which was dammed to prevent it slipping down the mountainside. The mine was deemed an orphan site because no organisation could be held accountable for fixing the mess.
Over the years, the tailings dam fell into disrepair and became unstable. In 1980 the Hauraki Catchment Board built a gravel embankment to stop the tailings slipping onto property further down the mountain.
Little progress had been made over 30 years to deal with the issues at Tui Mine but that all changed in the 2007 Budget, when money from the Ministry for the Environment’s Contaminated Sites Remediation Fund was earmarked to start the clean up of Tui Mine.
Since then the project partners have invested time, money and effort in planning to ensure the best long-term environmental outcomes and reduced ongoing maintenance costs for the remediation project.
According to the Waikato Regional Council, the three main issues arising from mining at the site are:
- The Tunakohoia stream, which flows through the Te Aroha township, has heavy metals leaching from the adits and from the tailings dam. These heavy metals include lead and cadmium.
- The Tui catchment is adjacent to, but separate from, the Tunakohoia catchment. The Tui catchment is also affected by heavy metals arising from the tailings dam.
- There is an abandoned mine tailing impoundment in the Tui catchment. Technical reports have found that this structure is at risk of collapse in a moderate seismic event or an extreme weather event. Such events could result in over 90,000 m3 of mine waste liquefying and flowing down the Tui stream past the edge of Te Aroha.
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