Story: Coal and coal mining

Coal was formed from plants laid down in peat swamps. Millions of years later, men mined it out in dirty conditions to power steel mills and winter fires.

Full story by Alan Sherwood and Jock Phillips
Main image: Waikato miners

The Short Story

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What is coal?

Coal is a rock that can burn, and it is made from carbon, water and minerals. It was formed millions of years ago when plants fell into peat swamps and were buried by heavy earth and rocks. Over a very long time, the weight of the rocks and heat in the ground turned the plants into coal.

How old is it?

Most of the world’s coal was formed 300–350 million years ago. New Zealand coals are much younger – they were made 30–70 million years ago.

Kinds of coal

There are different kinds of coal because three things can vary:

  • the kinds of plants that are buried. New Zealand coal was made from plants that did not exist when coal in other parts of the world was made.
  • how deeply the plants are buried. As coal becomes more compressed it gradually changes into different types of coal. It begins as peat, then becomes lignite, bituminous coal, and ends up as anthracite. New Zealand has very little anthracite.
  • the amount of minerals in the coal, such as clay, quartz and sulfur.

Coal deposits

Most coal is in the South Island’s West Coast, Otago and Southland. In the North Island, there are coalfields in Northland, Waikato and Taranaki.


Europeans began mining coal in New Zealand in the 1840s. At first, men went underground and dug out the coal with picks and shovels.

In the early 1900s men used compressed-air machines in mines to cut coal from the rock. They also used explosives to blast the rocks. The coal was loaded into railway wagons and taken out. In the later 1900s they used high-pressure water jets to cut the coal out, and it was carried to the earth’s surface in a flow of water.

In the 2000s mining was usually opencast. Earth and rock covering the coal was scraped and blasted away. When the coal was gone, the land was sometimes returned to its original state.


Underground mining was dangerous. Rocks fell, men were knocked over by the wagons carrying coal, there were explosions, and miners suffocated on poisonous gases.

An explosion at the Brunner mine in 1896 was New Zealand’s worst industrial accident. In all, 65 people were killed by toxic gas.

In the 2000s mining was safer because of government regulations, inspections and because opencast (rather than underground) mining methods were used.

Trade unionism

Many of the early miners came from Britain where there was a tradition of trade unionism to improve miners’ working conditions. Because of this, many New Zealand mining towns became centres of strong union activity. Some of the union leaders later became members of parliament.

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How to cite this page:

Alan Sherwood and Jock Phillips. 'Coal and coal mining', Te Ara - the Encyclopedia of New Zealand, updated 14-Sep-15