Tui mine

[4] In the 1960s, the Tui mine extracted copper, lead and zinc sulphides,[5] but had a problem with them being contaminated with mercury.

[5] The mine tailings are stored behind a dam in a large pool-like area which has an oxidised, solid surface layer.

[8] Waikato University had identified the problem of heavy metals contaminating water by 1984.

[9] The tailings dam was considered to be unstable and is leaching various minerals, including heavy metals, into neighbouring waterways and this adversely affected the stream ecology.

According to Environment Waikato, the Tui mine had three major environmental impacts; In 2007, the New Zealand Government announced that $9.88 million will be made available to clean up the site with the work scheduled to be completed by 2010.