Tui Mine
The Tui Mine site is located on the edge of the Kaimai range in the Waikato. The site is within the catchments of the Tui and Tunakohoia streams, both of which flow into the Waihou River at the base of Mount Te Aroha.
Mining remains
The remains consist of mine adits, waste rock, ore dumps, stockpiles and deposited tailings from ore processing. There are various water discharges from the site including adit drainage, natural catchment drainage and contaminated under drainage (low pH, high dissolved metals concentrations) from waste rock and tailings. Water pollution has entered the streams and made them unsafe for drinking, and unable to support aquatic life or human recreation.
Remains of the mining operation include this
concrete ore hopper and other earthworks
Technical reports have found that the tailings dam is at risk of collapse during a moderate seismic or extreme weather event. Such an event could result in over 90,000 m3 of mine waste liquefying and flowing down the Tui Stream past the edge of Te Aroha.
Remediation plan
In the 2007 Budget, money from the Ministry for the Environment's Contaminated Sites Remediation Fund was earmarked to start the clean up of Tui Mine. Since then project partners including Ministry for the Environment, Environment Waikato, Matamata-Piako District Council and Department of Conservation 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.
The aims are to:
- reduce the leaching of potentially toxic metals into the Tui and Tunakohoia streams and improve water quality.
- improve the stability of the tailings dam.
- restore the site so it can be used for public recreation in the future.
Depending on the outcome of the final trials and the granting of necessary consents, it is expected work on the underground mine workings will start in 2010. The aim is to complete the underground workings remediation and, subject to funding and consents, the tailings remediation by June 2011.