The Rotowaro Carbonisation Plant, also known as the Waikato Carbonisation Plant, was a

coal Coal is a combustible black or brownish-black sedimentary rock, formed as stratum, rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen ...

processing plant in the

Rotowaro Rotowaro was once a small coal mining township approximately 10 km west of Huntly in the Waikato region of New Zealand. The town was built especially for miners houses, but was entirely removed in the 1980s to make way for a large opencast ...

Huntly Huntly ( gd, Srath Bhalgaidh or ''Hunndaidh'') is a town in Aberdeenshire, Scotland, formerly known as Milton of Strathbogie or simply Strathbogie. It had a population of 4,460 in 2004 and is the site of Huntly Castle. Its neighbouring settleme ...

area,

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 List of islands of New Zealand, smaller islands. It is the ...

. It was also the first plant to use the Lurgi process in the Southern Hemisphere.

History

The first of its kind in the Southern Hemisphere, the plant was constructed in the late 1930s to convert otherwise unusable low-quality coal from the nearby Rotowaro Coal Mines into carbon

briquettes A briquette (; also spelled briquet) is a compressed block of coal dust or other combustible biomass material (e.g. charcoal, sawdust, wood chips, peat, or paper) used for fuel and kindling to start a fire. The term derives from the French word ' ...

, which were then used for domestic heating. The coal was carbonised using the Lurgi process, the result being coke and charcoal, with tar and creosote as by-products. The tar was used with the char to create the briquettes. Waste from the plant was discharged directly into the nearby Awaroa stream, which caused heavy pollution of the waterway. Following complaints about the pollution, Waikato Carbonisation Limited trialed a waste incineration programme, but the output of the plant exceeded the capacity of the burners. The excess was pumped into waste pools up until the plant's closure in 1985, when major fire caused a retort to explode. Various ownership changes lead to the complete abandonment of the plant. The plant currently sits on land administered by the Public Trust. Due to the historic nature of the site, the plant is classed as a Category I Historic Place by the

Historic Places Trust Heritage New Zealand Pouhere Taonga (initially the National Historic Places Trust and then, from 1963 to 2014, the New Zealand Historic Places Trust) ( mi, Pouhere Taonga) is a Crown entity with a membership of around 20,000 people that advocate ...

Pollution and cleanup

After the plant's closure, the plant was owned jointly by the Ministry of Energy and New Zealand Steel. Following the private sale of NZ Steel, the land on which the plant was located passed onto the local regional administration. An environmental evaluation of the site in the 1990s showed that the degree of contamination was at a hazardous level. As a result,

Environment Waikato Waikato () is a local government region of the upper North Island of New Zealand. It covers the Waikato District, Waipa District, Matamata-Piako District, South Waikato District and Hamilton City, as well as Hauraki, Coromandel Peninsula ...

completed a cleanup of the site,Environment Waikato – Cleanup Report
/ref> and removed all chemicals that posed a risk to human health or to the environment.

References

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External links

Extensive write-up on the NZ Historic Places Trust website
Heritage New Zealand Category 1 historic places in Waikato Buildings and structures in Waikato 1930s architecture in New Zealand History of Waikato Waikato District