U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2004–3089

September 2004

New Zealand Coal Resources

Printed on recycled paper

Introduction

The U.S. Geological Survey (USGS), in conjunction with partners from 

some 50 countries, is developing an integrated electronic database of coalquality information—the World Coal Quality Inventory (WoCQI). Information is provided for samples representing prominent coal beds in all of the 

major coal-producing countries, as well as coals from many of the smaller 

producers. This Fact Sheet summarizes coal-quality and coal-resource 

information for New Zealand.

Estimated In-Ground Resource

Coal is New Zealandʼs most abundant fossil fuel and has been an 

important energy source since the late nineteenth century. Coal beds 

are present in the Northland, Waikato, and Taranaki Coal Regions of 

the North Island and in the Nelson, West Coast, Canterbury, Otago, 

and Southland Coal Regions of the South Island (fig. 1). The total 

in-ground resource is estimated to be 15,600 million metric tons (Mt), 

of which about 8,700 Mt (56 percent) is recoverable (Barry and others, 

1994). Most of the resource is in the South Island; more than 13,000 Mt 

(84 percent) of the in-ground coal are lignite deposits there (table 1). 

The North Island in-ground resource of about 2,500 Mt (16 percent) is 

almost entirely subbituminous coal.

Coal Geology and Rank

With the exception of a few thin beds in pre-Cretaceous strata (Suggate, 1990), all New Zealand coal beds occur within late CretaceousCenozoic sedimentary units. Coal measures commonly rest unconformably on older basement rocks, often being overlain by marine 

sediments. Occasionally they occur above mid-Tertiary marine beds, 

at the base of overlying nonmarine beds, or rarely they are interbedded within a marine sequence. Differential subsidence has led to wide 

variations in thermal histories that cause extreme variations in rank, 

sometimes over short distances.

New Zealand coal beds range in rank from high-moisture lignite 

to low volatile bituminous, with minor anthracite occurrences resulting from local contact metamorphism (Suggate, 1959). Lignite and 

subbituminous coal are most abundant, constituting over 90 percent of 

in-ground and recoverable resources.

Coal Production and Mining Methods

Coal production reached 1 Mt in 1900 and 2 Mt by 1910. Production 

increased at a slower rate between 1910 and 1960, when annual production reached 3 Mt. From 1960 to 1992, annual production fluctuated 

between 2 Mt and 3.5 Mt, but it has exceeded 3 Mt since 1993. Over 

the last 20 years, the South Islandʼs West Coast region and the North 

Islandʼs Waikato region have been the largest producers. In 1996, the 

West Coast region produced 49 percent of New Zealandʼs coal, while 

41 percent was mined in the Waikato region. The Southland, central 

Otago, and Canterbury regions of the South Island produced 9 percent, 

1 percent, and a very small quantity, respectively. Total production 

figures by mining method for 1999 and 2000 appear in table 2. Total 

cumulative production from all New Zealand coal fields to the end of 

1998 was about 253 Mt (New Zealand Ministry of Commerce, 1998a).

Before 1940, less than 10 percent of production was from opencast 

mines. Opencast production has increased steadily to 80 percent of current production. Of the 3.5 Mt of coal produced in 1996, 47 percent was 

bituminous, 46 percent subbituminous, and 7 percent lignite. All bituminous production was from the West Coast region, and most subbituminous 

production was from the Waikato region, with much smaller amounts from 

the Southland and West Coast regions. Lignite production was from the 

Southland and Otago regions, with very small amounts from the Canterbury 

and West Coast regions (New Zealand Ministry of Commerce, 1998b).

Unique Coal Quality

Coal-quality parameters that make New Zealand coals unique in 

the world market include very low sulfur levels (0.25–0.35 percent), 

extremely low ash yields (about 1 weight percent), and low phosphorus content (0.005 percent from the Stockton Mine in the Buller 

Coal Field). In addition, bituminous coking coals from the West Coast 

region of the South Island may exhibit high free swell index numbers 

(9+) and high fluidity. All New Zealand coals exhibit high vitrinite 

composition, greater than 90 percent, with 95 percent common (Gillard 

and Moore, 1999). These characteristics allow New Zealand export 

coals to be used internationally as value-added products that bring 

coal blends into a target compositional range with the least additional 

volume. As a result, domestic coals that have marginal properties and 

other lower cost coals can be introduced into a blend or can be used to 

produce special products.

One consequence of the extremely low ash yields is an unusual 

inorganic chemical composition (Li and others, 2001). For example, 49 

samples from the Buller Coal Field (fig. 1) had an average ash yield of 

1.4 weight percent, with a minimum of 0.2 weight percent. For major 

elements in the 41 samples that had 10 weight percent ash or less, silicon and aluminum contents in the coals were commonly each less than 

1,000 parts per million (ppm) on a coal basis, and calcium contents 

were less than 400 ppm.

On an ash basis, the chemistry of the New Zealand coals is even 

more unusual. One sample from the Buller Coal Field had more than 

6,500 ppm nickel in the ash. Although arsenic content, in general, 

is low (less than 5 ppm in the coal), several samples had more than 

1,000 ppm in the ash, and two samples had more than 10,000 ppm. 

Coals from the North Island Waikato region have substantially higher 

boron and strontium contents (both about 300 ppm) than do the South 

Figure 1. Major coal regions (bold brown type) and coal fields (italic 

brown type) of New Zealand.
Island coals (generally less than 50 ppm boron and less than 30 ppm 

strontium, except for the Southland region, which has about 200 ppm 

boron). Waikato and Southland coals have 17 to 42 weight percent 

calcium oxide (CaO) in the ash, whereas coals from the West Coast 

region have about 1 weight percent. Despite low pyritic sulfur values of 

0.01–0.02 weight percent, coals from the Greymouth Coal Field in the 

West Coast region have the highest lead, antimony, and thallium values.

New Zealand Coal Exports

In the mid-1970s, awareness of the special qualities of New Zealandʼs 

premium-grade bituminous coals increased. Coal exports, mainly to 

Japan, increased steadily to about 0.5 Mt annually by 1990. Expansion 

of export markets during the 1990s led to a rapid increase in exports 

between 1992 and 1997, peaking at 1.6 Mt (44 percent of total production) for the year ending March 1997. For the year ending March 1998, 

however, exports decreased by 50 percent to 0.8 Mt (26 percent of 

total production), because of a significant decrease in exports to China, 

Japan, Australia, and Chile. Export volumes recovered to about 1.7 

Mt in 2001. New Zealandʼs largest coal export markets for 1998 were 

Japan, India, Chile, China, Australia, and Belgium (fig. 2). Specialquality coal is also in demand for specialized metallurgical and other 

industrial processes.

Future Trends

New Zealandʼs coal fields have been well explored, and its coal 

resources are quite well defined. Currently, little exploration for new 

reserves is taking place, and the industry is concentrating on improving knowledge of reserves within existing license areas. This status is 

likely to continue for some time. Electricity generation consumes about 

20 percent of New Zealandʼs domestic coal supply, and consumption 

is unlikely to increase in the future. New Zealand industry accounts for 

about 70 percent of domestic coal consumption, with steel manufacturing the largest customer.

Coal exporting has been the major growth area for the New Zealand 

coal industry since about 1990 and should continue to be a good 

prospect for the future. Although there has been demand for premiumquality bituminous coal, there is also a growing international market 

for thermal coals, such as New Zealandʼs lower grade bituminous and 

subbituminous coals.

References Cited

Barry, J.M., Duff, S.W., and MacFarlan, D.A.B., 1994, Coal resources 

of New Zealand: New Zealand Ministry of Commerce, Energy and 

Resources Division, Resource Information Report 16, 73 p.

Gillard, G.R., and Moore, T.A., 1999, New Zealand coal characteristics 

in the global scene: New Zealand Mining magazine, v. 25, p. 30–38.

Li, Z., Moore, T.A., and Weaver, S.D., 2001, Leaching of inorganics in 

the Cretaceous Greymouth coal beds, South Island, New Zealand: 

International Journal of Coal Geology, v. 47, p. 235–253.

New Zealand Ministry of Commerce, 1998a, New Zealand Energy 

Data File, July 1998: Wellington.

New Zealand Ministry of Commerce, 1998b, New Zealand Annual 

Mining Review 1996: Wellington.

Suggate, R.P., 1959, New Zealand coals—Their geological setting and 

its influence on their properties: Department of Scientific and Industrial Research Bulletin 134, 112 p.

Suggate, R.P., 1990, Coal ranks in Permian-Lower Cretaceous rocks of 

New Zealand: New Zealand Journal of Geology and Geophysics, v. 

33, p. 163–172.

By Tim A. Moore and Robert B. Finkelman

For additional information

Tim A. Moore

Department of Geological Science

University of Canterbury

Private Bag 4800

Christchurch, NZ

E-mail: tim.moore@canterbury.ac.nz

Robert B. Finkelman

U.S. Geological Survey

956 National Center

Reston, VA 20192, U.S.A.

Telephone: (703) 648–6473

E-mail: rbf@usgs.gov

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Figure 2. New Zealand coal export markets in 1998.