Contribution of mining to the economy
All modern communities use mineral resources extracted from beneath the ground – New Zealand examples include:
- clay for crockery, bricks and tiles
- ironsands for the manufacture of steel
- oil, gas and coal to provide heat and energy sources for electricity generation
- limestone for agricultural fertiliser.
New Zealand is self-sufficient in many mineral resources, and exports substantial amounts of gold, silver, ironsands and high-grade coal. The mining industry contributes to several major sectors of the economy, including agriculture, energy, construction, transport and manufacturing.
In 2004 the value of production from mining underground resources (excluding oil and gas) was $1,142 million, which is just under 1% of gross domestic product. This has grown over 45% over the five years since 1999, buoyed by strong economic conditions and growth in mineral exports.
What is a mineral?
The meaning of the term ‘mineral’ varies according to the context. When applied to mining, it is used for natural substances that are extracted from the earth. This includes material as varied as oil, coal, aggregate, limestone and iron sand.
Pastoral agriculture is dependent on the availability of superphosphate. Only limited amounts of phosphate and sulfur are available in New Zealand so these must be imported and processed to make superphosphate. The other main mineral imports are copper, zinc, gypsum, lead, magnesium, manganese, nickel and titanium oxide.
Although some light oil is produced in Taranaki, mainly from the Kāpuni and Māui gas fields, this is not sufficient for national energy needs, especially for transport fuel. Imported oil is processed at the Marsden Point refinery (in Northland) to produce petroleum and a range of other oil products.
Underground to opencast
The mention of mining conjures up visions of dark underground mines, but the nature of mining has changed dramatically since the mid-20th century. There is now little underground mining in New Zealand, and most mines are opencast pits that are excavated with explosives and earth-moving machinery. In practical terms, there is no distinction between a quarry and an opencast mine. The labour-intensive aspects of mining have largely disappeared. The workforce is smaller, and there are few unskilled jobs.
Mining traditionally had a bad reputation because of the high accident rate. Safety standards are dramatically higher than in the past, and the number of deaths and accidents has fallen to low levels. There is no longer public tolerance of the high level of accidents traditionally associated with mining and quarrying.
A clean pair of pyjamas
It was a tradition in coalmining settlements that a miner’s wife kept aside a clean pair of pyjamas that could be used to lay out her husband or sons if they were killed in the mine. Accidents were accepted as part of the natural order for those who worked underground.
Mining, like other land uses, can cause significant environmental problems. Some past mining practices were highly destructive. For example, dredging in Otago and on the West Coast destroyed large areas of river flats, leaving behind unsightly trails of tailings. Protests and community concerns about the effects of mining have gradually resulted in higher environmental standards. All mining proposals are now evaluated in terms of the Resource Management Act 1991.
Since the 1980s, mining permits have included requirements to undertake land rehabilitation after mining has been completed. At its best, land that has been mined and rehabilitated is not easily distinguished from land that has never been mined. Agricultural scientists and engineers have developed considerable expertise in land rehabilitation.
Recycling of a range of materials helps minimise the costs and effects of mining as well as the need to import products. For example, a substantial amount of recycled iron and steel is used as feedstock in the New Zealand Steel works at Glenbrook. Motor oil can be cleaned and reused. Metal products such as copper wire and aluminium cans, already the products of smelting metal ores, can be readily reused.