Waitewhena Coalfield, Taranaki

Waitewhena Coalfield, about 15km north of Ohura, is one of several exposed in the Taranaki Coal Region. Prospecting began in 1916. Between 1934 and 1979, 20 opencast and 9 underground mines have produced a total of 1,677,000 tonnes of coal from a seam 1-4.5m thick. The economic seam is at the base of the extensive Maryville Coal Measures of Lower Miocene age, which are overlain and underlain by marine sandstones. The coal is sub-bituminous B of low to medium ash and mainly medium sulphur. Inferred coal in ground reserves more than 2m thick are estimated at 49 million tonnes of which 5.4 million tonnes might be opencastable. A further 21 million tonnes of inferred coal in ground 1-2m thick is estimated, of which 1.7 million tonnes might be opencastable. Mapping and exposure by mining show disruption of the seam by predominantly normal faults of up to 50m throw.