An Overview
Since 1882 coal mining has been a major industry on the West Coast. In 2005, 2.5 million tonnes of coal was produced. It is the dominant industry in the Buller District.
Geology
West Coast coal seams were mainly deposited within the Paparoa Trough, an elongated fault-bound basin that developed in the Cretaceous Period.
The late Cretaceous age Paparoa Coal Measures are restricted to the Greymouth, Pike River and Fox River coalfields. Early Tertiary Brunner Coal Measures are widespread and Miocene Rotokohu Coal Measures are present in the Inangahua Coalfield.
Rapid changes in sedimentation patterns, irregular lensoidal seams and complex structure (faulting and folding) are common within the Paparoa and Brunner Coal Measures.
Coal Quality
The West Coast contains virtually all New Zealand’s bituminous (coking) coals. Compared to overseas coals, ash levels are low and in some seams exceptionally low. Sulphur within the Paparoa and Rotokohu coal seams is mostly low, but the Brunner coal seams tend to be high sulphur although some areas have low sulphur contents.
The bituminous coals of the Greymouth, Buller and Pike River coalfields contain some very high swelling coal. As with most New Zealand coals there are high levels of reactives (vitrinite) present.
Coal Utilisation
Prior to 1980, West Coast coal was used within New Zealand mainly for domestic and industrial purposes (steam raising and gas works).
Most West Coast coal is now exported for use as metallurgical coke in the steel making industry. Other uses for West Coast coal are in the production of activated carbon (water, air purification) silicon metal and ferro-silicon.
Domestically West Coast coal is used for industrial and household heating, steam raising at dairy factories and as a fuel at the Cape Foulwind cement works.
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Coal Resources
Potentially Recoverable Coal Resources |
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| Type |
Recoverable resources (tonnes) |
| Bituminous Coking |
57,000,000 |
| Bituminous Soft Coking/Thermal |
122,000,000 |
| Sub-Bituminous Thermal |
26,000,000 |
| TOTAL |
205,000,000 |
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| With potentially recoverable resources of 205 million tonnes, there are opportunities for significant increases in coal exports and also to provide fuel for a local power station. |
Coal Mining
Up to 1973, most coal was extracted by underground methods. In the Buller Coalfield, all coal is now won by opencast mining, but underground methods are necessary for the deeper coal seams of the Greymouth Coalfield.
Mining History
Coal was first mined at Brunner in 1864 but it was not until 1882, when rail and ports were completed, that large scale mining commenced. Production peaked in 1914, when 1,340,000 tonnes were produced with 2550 employees. Following World War 2 there was a significant production decline as hydro-electricity and diesel fuel became more available. Loss of markets resulted in the closure of a number of mines.
Exports of coking coal to Japan from Stockton Mine commenced in 1980 and since 1990 around 90% of West Coast coal production has been exported. Production has been at record levels since 2002 mainly because of large increases at Stockton Mine.
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New Zealand’s Bituminous Coals |
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| The West Coast contains virtually all New Zealand’s bituminous (coking) coals. Compared to overseas coals, ash levels are low and in some seams exceptionally low. |
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| With potentially recoverable resources of 205 million tonnes, there are opportunities for significant increases in coal exports and also to provide fuel for a West Coast power station. |
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| Exports of coking coal to Japan from Stockton Mine commenced in 1980 and since 1990 around 90% of West Coast coal production has been exported. Production has been at record levels since 2002 mainly because of large increases at Stockton Mine. |
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| Coal stockpile at Casacade MineCoal stockpile at Casacade Mine |
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