Jan Wright: Costly ecological timebomb ticks in dated mining rights

Taxpayers will pay $10 million to contain mercury at the abandoned Tui mine in Te Aroha. Photo / Sarah Ivey

Mining has long played a major role in New Zealand's history, and has created controversy in regard to its effects on the environment.

The environmental effects of coal mining in particular have been of concern to the Parliamentary Commissioner for the Environment.

In 1992, the first commissioner, Helen Hughes, released a report about her concerns regarding the environmental management of coal mining.

Then Dr Morgan Williams, as the second commissioner, made a commitment in 2006 to investigate the environmental management of Solid Energy's coal mine at Stockton, on the West Coast of the South Island.

Last year, I set out to determine what improvements had been made since Dr Williams' report.

Solid Energy has made significant progress. Investment into engineering solutions and implementing an environmental management system have paid off.

The water of the scenic Ngakawau River, for example, now has lower levels of sediment and is much less acidic than in 2006, although it is too early to assess the success of the restoration of soil and vegetation.

While carrying out this investigation I became aware of another issue of national significance.

Stockton mine, it turns out, is operating under a licence granted many years ago, under an old regime with few environmental safeguards. Indeed, Solid Energy's improvements at Stockton are not enforceable, but are voluntary.

The mining licence granted under the old regime contains environmental conditions that are weak and difficult to enforce.

The improvements at Stockton mine have been made in spite of the regulatory regime under which it operates, not because of it.

You may be wondering what the environmental condition of a coal mine on the West Coast of the South Island has to do with the rest of the country. A great deal.

My investigation discovered there are more than 100 of these old mining licences still in existence, covering a combined area equal to more than three-quarters the size of Lake Taupo. The majority are in Waikato or on the West Coast.

These old licences with their weak environmental protection are from an era when we thought children didn't need to "buckle-up" in a car. Over time our values about the environment have shifted as have our concerns about child safety, yet the environmental regime of these old licences still dates back to that former time.