Mineral resource assessment of the Northland region, New Zealand

SR 2007-006-pdf
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Christie, A.B.; Barker, R.G. 2007 Mineral resource assessment of the Northland region, New Zealand. Lower Hutt, NZ.: GNS Science. GNS Science report 2007/06. 169 p. + 1 CD

Abstract: The Northland region contains a wide variety of mineral commodities and currently produces high quality ceramic clays, limestone for cement and agriculture, and rock and sand aggregates. Antimony, coal, copper, diatomite, kaolinite clay, kauri gum, manganese, mercury, peat, serpentine, silica sand and silver have been mined in the past and there are prospects for aluminium, bentonite, chrome, feldspar sand, gold, lead, nickel, phosphate, zeolite and zinc. Resources of rock aggregate, sand and limestone have not been quantified, but are estimated to be large and sufficient to meet foreseeable local demand. Previous estimates have been used for sub-bituminous and bituminous coal (23 Mt valued at $1,150 M), lignite (31 Mt valued at $620 M) and peat (300 Mt valued at $12,000 M). Other potential mineral resources have been estimated using a three step process involving mineral deposit models, a geographic information system (GIS) of spatial data sets, and a counting method of assessment. Estimates of value for 16 metallic mineral deposit types total NZ$5,235 million, and for 14 non-metallic mineral deposit types they total NZ$28,019 million. A scenario is proposed whereby the value of Northland's mineral production could increase from the current NZ$58 million to more than NZ$354 million annually by: An increase in production of aggregate and limestone to past maximum annual levels; Development of a gold-silver mine; Development of a second metalliferous mine (e.g. aluminium, copper or gold-silver); Development of a second halloysite clay mine; Reintroduction of silica sand mining; and Small mining operations in one or more commodities such as bentonite, coal, feldspar, kaolinite clay, kauri gum, peat and zeolite. This scenario would be possible over a 15 year time-frame, provided that 1, There is a sufficient level of exploration to define the new resources and 2, New discoveries can be developed. Although the assessed potential value of non-metal resources is about 5 times higher than the value of metals, it is the metals that contribute most to the potential increase in the value of production. Markets for the metals are highly developed and are not a barrier to new production. The development of non-metals is constrained by the size of the market within the region (and New Zealand). Developing markets for high value, specialised industrial minerals such as halloysite clay requires substantial investment and a long term commitment. Attracting explorers to work in the region will require marketing Northland’s mineral potential to the international exploration community along with identifying and overcoming barriers to exploration and mineral development. (auth)