Decade since mountain’s healing began
It was rated as one of New Zealand’s worst environmental hazards.
turns back the pages of the Piako Post for our
series.
It has been just over a decade since ‘‘the scar of Tui Mine’’ was sealed and Mt Te Aroha was finally able to begin healing.
That’s how the Piako Post reported on the completion of the $21.7 million remediation project of the former mine, in its February 27, 2016 issue.
The work on the heavily contaminated site, on the lower slopes of the landmark mountain, began in 2007 was completed in June, 2016.
The project involved Waikato Regional Council, Ministry for the Environment, Matamata-Piako District Council, Department of Conversation and iwi.
An iwi advisory group, established as part of the remediation group, developed a cultural monitoring plan that outlined a vision to ‘‘accelerate the regeneration’’ of the maunga.
The remediation project aimed to bring the mountain back to its natural state. The abandoned cop- per, lead and zinc mine had leaked toxic heavy meals and acids into nearby streams for decades.
Regional council said ‘‘specialised activity’’ continued at the mine today. It included maintenance works for access roads, monitoring installations (flow measurement weirs), drain clearing, grass mowing, weed control, planting and lime application as required are permitted.
‘‘The site is secure in the sense that public vehicle access is not allowed without permission (gate on access road is closed). The site is open for tramping. Access into the underground portals is not allowed without permission (gates at portals are closed).’’
The council said the rate at which contaminants were leaching into the Tui Stream has been reduced. Water quality meets recreational use criteria. The rate at which contaminants were leach- ing into the Tunakohoia Stream northern branch has been reduced significantly too.
Interim monitoring was scheduled for August – December 2017 with a report due in February/ March 2018.
The Matamata-Piako District Council applied for resource consent a year ago, for extra work related to tailings dumped alongside the Tui access road embankment, which forms the right bank of the northern branch of the Tunakohoia Stream.
‘‘This site was recognised during the initial investigation of the overall Tui Mine remediation project. However, it was deemed to be a relatively minor component of the overall situation,’’ regional council said.
Monitoring showed the initial remediation treatment was not as effective as wanted. Lime was applied on the surface of the area but this did not successfully neutralise and stabilise the acidity of material in this area that was affecting water quality.
So another method was used, mixing lime with the tailings and compaction of the mixed material was recommended and approved by the project governance group by December 2015.