Location: New Zealand
Surnames/tags: New Zealand Mining
Contact: New Zealand Project
Coal Mining History
|Miners in Waikato|
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.
- 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.
|Coal Miners, Puponga Mine, ca 1880s|
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 generally safer because of government regulations, inspections and because opencast (rather than underground) mining methods were used.
Explosions at the Pike River mine in 2010, which resulted in the deaths of 29 men, exposed ongoing safety issues for miners.
The government set up Workplace New Zealand to be responsible for all workplace safety issues, with a designated High Hazards Unit covering industries such as mining and petroleum exploration.
- 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.
- Coal Resources
A comprehensive coal survey made between 1976 and 1989 established that New Zealand had an estimated 15 billion tonnes of in-ground coal. The amount that could be recovered depends on geological, engineering, economic and environmental constraints. The largest resource, the lignites of Southland and Otago, has technically recoverable reserves of about 75,000 petajoules (PJ) of energy – by comparison, the huge Māui gas field originally contained 4,500 PJ.
- North Island Resources
North Island coalfields are located in Northland, the Waikato and northern Taranaki. Most known areas of sub-bituminous coal in Northland have been worked out, and the last mine closed in 1955.
Thirteen coalfields, extending from Drury (30 kilometres south of Auckland) to Mangapēhi (20 kilometres south of Te Kūiti), are geologically grouped as Waikato coalfields. In these, there are 2,078 million tonnes of in-ground coal. However, much of this is in deep seams, which will be very difficult to mine by conventional means. Techniques such as underground coal gasification or coal seam methane production may be needed to extract the energy.
Waikato coals are all sub-bituminous, laid down in the Eocene and Oligocene periods. Seams in the north of the region generally have low to medium ash and low sulfur contents, whereas seams in the south have medium to high ash and sulfur contents. The main seam is typically 3–10 metres thick, but reaches 20 metres or more in parts of the Huntly and Waikare coalfields. Some of the thinner seams have been worked out.
There are five coalfields in northern Taranaki, of which the Mōkau coalfield near the west coast is the largest. Previous mining has been on a small scale, and there has been no production since the last mine, in the Waitewhena coalfield, closed in 1990. In-ground resources amount to 380 million tonnes of sub-bituminous coal.
- West Coast
The South Island’s West Coast region contains New Zealand’s only bituminous coals. Some have unusual properties that are in demand in international coal markets. There are 13 coalfields of various sizes between Greymouth and Seddonville (40 kilometres north of Westport). The Buller, Greymouth, Pike River and Reefton coalfields are the most economically important.
There are 983 million tonnes of in-ground coal in the region. Over three-quarters of recoverable reserves are in the Greymouth coalfield (mostly underground) and Buller coalfield (mostly opencast). After an explosion at the Pike River mine in 2010 when 29 men were killed, the government decided that there would be no further mining in the area, which is to be added to the Paparoa National Park.
There are two main types of coal measures (coal-bearing sedimentary rocks): 1. late Cretaceous to earliest Tertiary Paparoa coal measures, and 2. Eocene Brunner coal measures. Both Paparoa and Brunner coalfields contain seams up to 20 metres thick. Paparoa coals are characterised by low ash and sulfur contents, and Brunner coals have lower ash and varying sulfur content.
West Coast coals are almost all bituminous, with a small deposit of anthracite at Fox River. Their high quality and low level of mineral contaminants enable them to command premium prices on world markets.
- Otago and Southland
The bulk of New Zealand’s coal resources are in the south of the South Island. Over 7 billion tonnes of mineable lignite resources have been proven in Otago and Southland, enough to provide a significant proportion of New Zealand’s energy needs for a long period.
Otago coalfields include very large lignite deposits in Central Otago, the Kaitangata coalfield south of Dunedin, and several smaller coalfields. Central Otago lignites are in seams up to 90 metres thick and typically have 40%–50% in-ground moisture and low to medium ash and low sulfur contents.
The eastern Southland lignite fields are comparable to other large deposits in the world and are, by far, New Zealand’s biggest fossil fuel energy resource. They form extensive, multiple seams up to 18 metres thick, and typically have 40%–65% in-ground moisture and low to medium ash and low sulfur contents.
The Ōhai coalfield in central Southland has seams up to 23 metres thick containing sub-bituminous and bituminous coals, generally with low ash and sulfur contents.
The 19th Century
Ring, James, 1856-1939. Group including the Governor, Sir William Jervois, during his visit to the coal mine at Brunnerton - Photograph taken by James Ring. Kay, R A, fl 1960 : Photographs taken in Grey County, West Coast. Ref: 1/2-018519-F. Alexander Turnbull Library, Wellington, New Zealand. /records/22802550
It is said that Tainui Māori knew that waro (coal) had heating properties and used it for cooking, while the first European use was probably at Shag Point on the Otago coast, where whalers used coal to heat trypots for rendering blubber.
The settlers of the 1840s, knowing that Britain’s industrial revolution had been fueled by coal, quickly prospected for it. Thomas Brunner recorded coal in the Grey River in 1848, and by 1860 most of the main fields had been discovered – in that year Julius Haast noted the potential of what became the Denniston plateau in Buller.
- Early Mines
The first New Zealand mine was established in 1849 at Saddle Hill, Dunedin, and over the next 20 years a number of small working mines were set up. Most were mere holes in the ground, employing a handful of people, often on a seasonal basis, and catering for the local market. In the south, mining began at Kaitangata in 1858, at Green Island in 1861, and Shag Point the next year. The Malvern Hills mine in Canterbury was worked from 1862, and in Golden Bay there was a small mine at Collingwood from 1868. In the North Island the largest operation, which started in 1865, was at Kawakawa.
In the 1870s promoters imagined a thriving coal industry as the basis for New Zealand’s industrial future. Coal was essential to Julius Vogel’s expansionist immigration and transport policies. Trains were fired by coal, and increasingly, ships’ sails were replaced by coal-powered steam engines. During that decade, coal became New Zealand’s fifth-largest import, mostly from Newcastle in Australia. With such demand, mining attracted investors.
The first field with major potential was at Brunner in the Grey River valley. Mining had begun there in a small way in 1864. Once a railway to Greymouth replaced barges in 1876, and a new bridge across the Grey River was completed the next year, the Brunner mines were able to expand. A new breakwater to counteract the harbour bar also helped. By 1888 the field was producing a third of New Zealand’s coal output, which had tripled from 10 years before. Coking and brickworks developed as spin-offs. Coke was made by burning coal to remove the impurities and produce a smokeless fuel. Four years later another field was opened further up the valley at Blackball.</p>
Transport improvements were the key to Buller’s success. The quality of the coal on the Denniston plateau, some 600 metres high, had been quickly recognised. But it was the completion of the cable railway known as the Denniston incline in 1879, and the branch rail line to Westport that made mining the field possible. The incline gained a reputation as the ‘eighth wonder of the world’, being just over 1.5 kilometres long, with a very steep gradient.
Denniston was funded by a group of Dunedin businessmen, including James Mills of the Union Steam Ship Company. By 1887, through its majority ownership of the Westport Coal Company, the Union Company had effective control of the Denniston mine to add to its buy-out of the Brunner mines the previous year. This ‘southern octopus’ monopolised the West Coast fields, which by 1896 were producing over half of New Zealand’s coal.
- Otago and Waikato
In Otago, the Kaitangata mines were employing over 140 men in 1896 (compared with 315 at Denniston), and at Huntly in the Waikato, where mining had begun in 1876, there were over 100. Many small operations sprang up. In 1896 there were 163 mines, but only 20 employed more than 20 men. By 1900 New Zealand was producing over a million tons of coal, a six-fold increase since records began in 1878, and over eight times the amount being imported. Coal had become the country’s main energy source.
- The 20th Century
From 1900 to 1914 New Zealand coal production more than doubled to 2.25 million tonnes, a figure it would not consistently exceed until the Second World War. This dramatic increase was due to the demands of steamships and railways, the export-driven growth of dairy factories and freezing works, and the development of municipal gas works that burnt coal to produce domestic gas.
The most spectacular growth came in Buller, where the Westport Coal Company developed major fields at Millerton and Stockton. By 1914, one-third of New Zealand’s coal came from the Buller mines.
- State Coal Mines
|Railbridge across the Waikato, 1941|
The Grey River fields saw falling production in the Brunner area, but in 1901 Richard Seddon’s government created State Coal Mines to challenge the Union Steam Ship Company’s coal monopoly and improve safety. The first state mine was at Seddonville in Buller. The state’s Point Elizabeth mine, established near Rūnanga, (the "tribal or public assembly, conference, council"), in 1904, revived mining in the Grey River valley. By 1914 the area was producing a quarter of the country’s coal, and the West Coast, in all, contributed three-fifths.
- Waikato Fields
Further south, the Kaitangata field remained static (contributing less than 13% in 1914) as Dunedin lost its economic pre-eminence. But there was growth in the Huntly area, where dairying and the industrial and domestic demand of Auckland provided strong local markets. Production quadrupled in these years to reach 15% of the national total. During the First World War a bridge was completed across the Waikato River and this opened up new areas for mining in the hills to the west – at Pukemiro, Glen Afton and Rotowaro.
In the interwar years the West Coast suffered as ships turned to oil in place of coal. By the mid-1930s the Waikato fields were producing as much coal as the West Coast fields. The economic depression encouraged a revival of small-scale mining as miners, laid off from the large operations, developed cooperatives and re-opened abandoned workings. By mid-1930 there were several hundred such operations.
- Second World War
The outbreak of war in 1939 gave a new value to coal. From 1942, coal mining became an essential industry and miners were prohibited from changing jobs. The Labour government began taking over pits, especially if they looked like failing. By 1942 all the mines in the Grey River valley were nationalised, as were the Waikato mines. By the late 1940s state-owned mines were producing over half of New Zealand’s coal, and in 1948 coal deposits were nationalised, although this was quickly reversed by the National government two years later.
Another important development of the period was the beginning of opencast mining on a substantial scale. In this method coal was mined from the surface rather than from shafts. At the start of the war only 2% of coal was mined this way. By 1945 the figure was over 16%. In 1960 when coal production reached a post-war peak of over 3 million tonnes, 37% came from opencast mines. By 1979, when production had fallen to under 2 million tonnes, opencast mining contributed 69%.
The fall in the 1960s and 1970s was particularly severe on the West Coast, partly because bituminous coal, once the fuel of ships and trains, was no longer in demand. By then, ships had switched to oil and the railways were in decline. In addition, gas was increasingly being replaced by hydro-electric power and eventually by Māui natural gas, while household use of coal had fallen in 1972 to a quarter of the 1949 level. Twelve significant mines closed between 1967 and 1974.
There was evidence of decline in coal mining everywhere – the number of mines fell from 216 in 1953 to 78 in 1973; the number of miners fell from over 5,000 to about 1,500, and almost half of these were over 45 years old. In the same period, the Grey River valley workforce fell to a quarter, the Buller workers to a third. Denniston, which once had 1,308 people living there, had only four in 1981.
- The Late 20th & 21st Centuries
From the early 1980s there was a slow revival in coal mining, which picked up dramatically in the 1990s. By 2003 there was a national production of over 5 million tonnes, which was double the 1990 figure. In 1987 State Coal Mines was transformed into a state-owned enterprise, Coal Corp, and by 2003, rebranded as Solid Energy, was producing 80% of the nation’s coal.
- Local markets
As the price of oil rose, coal proved more economic for local industries, especially electricity and steel. In 1983 the dual-fuel 1,000MW Huntly power station was commissioned, and it initially ran mainly on gas. However, as gas supplies tightened in the early 2000s, it used over 1 million tonnes of coal a year, sourced from several Waikato mines and some imports. Running at maximum capacity on coal, the Huntly power station can use over 2 million tonnes of coal a year.
|Mangatangi Coal Mine.|
The second major domestic market was the steel mill at Glenbrook, south of Auckland. This used iron sand from the west coast of the North Island and coal from the Waikato to produce about 600,000 tonnes of flat-steel products for domestic and export use.
The dairy industry, one of New Zealand’s biggest export earners, used coal extensively. Fonterra Co-operative Group operated a subsidiary coal mining company, Glencoal Energy, to supply coal to its dairy plants and the Huntly power station. The cement, timber, meat-processing and health sectors used coal, either for direct heat supply or cogeneration. Cogeneration produces both heat and electricity, and it increases the efficiency of burning coal by up to 90%.
- Export markets
Some New Zealand coals have properties that are in demand internationally, and a strong coal export industry developed following the trial shipments to Japan in 1976. All export coal came from mines on the West Coast of the South Island. Solid Energy was the major exporter, shipping 2.14 million tonnes in 2004. Most exports were of premium-quality coking coal for steel making, sent mainly to Japan, and also to India, South Africa, China and Brazil. There was an increasing export market for thermal coal for steam raising and power generation. In 2005, New Zealand was still a small contributor in the international coal market (less than 0.5% of all coal shipped), but it was clearly growing.
In the early 2000s there were about 45 coal mines in New Zealand, although some produced only a few thousand tonnes a year. About 40% of production was from the Waikato region, where the two major mines were Rotowaro (an opencast mine) and Huntly East, the only underground mine in the North Island. The Glenbrook steel mill and the Huntly thermal power station were the main users of Waikato coal.
- South Island
The most spectacular growth in mining in the early 21st century came on the West Coast. At Stockton in the Buller coalfield (the country’s largest operation with an annual output of over 1.5 million tonnes) a 2.2-kilometre aerial ropeway was used to bring coal down from the Denniston plateau.
The one area where growth in mining was limited was in the lignite fields of Southland, New Zealand’s largest coal resource.
The Future of Coal
In 2005 coal contributed about 10% of New Zealand‘s electricity supply and 12% of its primary energy supply. It seems likely these proportions will increase. The environmental obstacles to new large-scale geothermal and hydro development schemes, the high cost of other renewable energy sources and imported oil, and the failure to discover large new gas fields in New Zealand make coal a major option for a secure energy supply at a reasonable price.
New Zealand’s industries need low-cost energy to remain internationally competitive. New Zealand has large resources of coal in several regions and will be able to supply a high proportion of the non-transportation energy requirements for hundreds of years at a reasonable cost. The lignite resource has the potential to supply transport fuels economically as world oil prices increase.
Coal is widely perceived to be a polluting fuel, but in developed economies this perception is largely a hangover from the belching images of smokestacks of the industrial revolution. Pollution from smoke and soot was largely under control by the end of the 1970s, and by the 2000s environmentally acceptable levels of sulfur dioxide and nitrogen oxide emissions were readily achievable at ever-reducing costs.
- Carbon Dioxide
The main concern surrounding increased use of coal is its contribution to atmospheric concentrations of carbon dioxide – a cause of potentially adverse climate change.
Coal cannot be burnt without producing carbon dioxide. Because coal is such an important energy source worldwide, massive efforts are being made by many countries to find ways to reduce or eliminate emissions. These focus on: carbon capture, which involves the removal of carbon dioxide either directly from the exhaust streams of industrial or power plants or indirectly from the atmosphere carbon sequestration, which is the disposal of carbon dioxide in a natural storage compartment such as depleted underground oil or gas reservoirs.