Tui Mine remediation

This page outlines the progress of the Tui Mine remediation project, including details of the project’s funding and its two phases of completion. This page also provides links to resources about the Tui Mine project, including information brochures and Waikato District Council reports. 

Project funding and details

Discharges from the Tui Mine workings and the associated tailings dam were significantly impacting on water quality in the Tunakohoia and Tui Streams. The tailings dam structure was geotechnically unstable and in a large seismic or storm event there was a risk it could have failed which would have resulted in a significant discharge of contaminants into the environment.

The Government provided $20.35 million (excluding GST) for the Tui Mine remediation project.

Waikato Regional Council and Matamata-Piako District Council also provided funding for the Tui Mine remediation project.   

The Tui Mine remediation project has been successfully completed and its objective to reduce the risks to health and the environment has been met.

In May 2013, the Minister for the Environment Hon. Amy Adams visited the site and officially closed the works. The Minister congratulated and thanked the project partners and the site contractors for a job well done.

Project phases

The project was completed in two phases.

Phase one

Phase one involved preparatory work (detailed design, site establishment, access road) and the treatment of the old underground mine workings.
The old mine workings discharge contaminated water into the Tunakohoia Stream.

During phase one, the lowest workings were plugged with engineered concrete bulkhead, and alkaline solution (lime) was injected into the ground and upper workings to counter the strongly acidic conditions.

Phase two

Phase two involved remediating the tailings dam area that posed a risk of collapse and discharged contaminants to the Tui Stream.  The tailings were amended with cement and lime and compacted until they were firm enough to form a secure mound on the site. The mound was capped with soil and grassed, and appropriate drainage installed to prevent erosion.

Monitoring

Although the project’s physical works have been successful completed, the project team shall, until 2016, continue to monitor the water quality in the Tunakohoia and Tui Streams. Monitoring to date has already shown improvements in water quality and in-stream ecology.

Find out more

Tui mine remediation project [Waikato Regional Council website]
Information about the Tui mine remediation project including plans, reports, newsletters, and and information brochure. 

Tui Mine clean-up media release [Beehive website]

Reviewed:
03/08/15