Background

Northland contains a wide variety of minerals and currently produces rock and sand aggregates, limestone for cement and agriculture, and high quality ceramic clays for export. 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, chromium, feldspar sand, gold, lead, nickel, phosphate, zeolite and zinc.

	Golden Bay Cement, Whangarei

The minerals industry forms an essential part of the Northland economy. Aggregate production underpins infrastructure and building development. Limestone used as fertiliser supports the agricultural industry. In terms of end value, cement manufacture is one of the most important industries in Northland, worth more than $100 million per year. High value china clay is a significant export commodity.

Mining History

Northland has a diverse mining history. Minerals continue to support the economic progress of the region:

• Coal was discovered in 1861 at Kawakawa, and the Hikurangi coalfield north of Whangarei produced more than 4 million tonnes of coal between 1890 and 1960
• Copper was produced from Pakotai (west of Whangarei) between 1890 and 1905, and from a number of other locations until the 1950s
• Antimony was produced near Russell from 1907
• Mercury has been worked at Ngawha and Puhipuhi from 1918
• Diatomite was produced at a quarry near Kamo from 1938-1952
• Alumina deposits were discovered at Matauri Bay in 1960
• Silica sand has been produced from Parengarenga for glass making in Auckland
• Halloysite clay – The Matauri Bay development followed trials in the 1960s and continues today, being operated by Imerys tableware.
• Limestone has been produced since last century for agricultural use
• Cement has been made at Portland near Whangarei since initial trials in the 1870s. The Golden Bay Cement operation there is now New Zealand’s largest cement manufacturer
• Aggregate is produced from numerous quarries, mainly for use in Northland, and the rapidly growing areas north of Auckland.

Resource Potential

	Drilling Hazelbrook gold prospect near Kaeo

Recent studies by GNS Science (the Government’s geological Crown Research Institute) and the NZ Institute of Economic Research have shown that Northland has resource potential worth more than $5 billion for metals and as much as $28 billion for other minerals. A scenario based on these results proposes that the annual value of Northland’s mineral output could increase from the current level of $58 million (excluding cement) to more than $350 million over a period of 15 years. The reports are accessible here:

Mineral Resource Assessment of Northland, May 2007 (5.9 MB)

Northland's Mineral Resources - Potential Economic Impacts, May 2007 (375 KB)

Mineral Potential of Northland - Summary (41 KB)

Gold and Silver

Gold and silver have been discovered at a number of locations in the east of the region. A prospect at Puhipuhi north of Whangarei has been investigated in detail, including drilling which has given tantalising results. Exploration for gold and silver is continuing here, and elsewhere in the region.

The information produced by past geological investigations and exploration activity is retained by the Crown Minerals Group of the Ministry of Economic Development. This information is now being used to help target the renewed exploration activity.

Other metals

The geology of Northland is complex and diverse, and a wide range of metallic minerals have been reported here, with a number being produced on a small scale. Northland is under-explored (compared with other parts on NZ and overseas) and further exploration could lead to new discoveries being made.

Potential has been recognised for

• Copper, lead and zinc in several different deposit types
• Copper-gold deposits
• Manganese
• Nickel and chromium
• Antimony
• Mercury
• Aluminium

Industrial minerals

The china clay operation at Matauri Bay that produces the kaolin-like mineral halloysite, is an example of a high value industrial mineral generating export income for New Zealand, and making a significant economic and social contribution to Northland.

Potential exists for the discovery and development of other industrial minerals in the region. Those recorded in the district include diatomite and fullers earth that are used in a wide range of industrial processes, silica sand and feldspar sand used particularly for making glass, fireclay, and barite. Clay minerals or hydrothermal origin like those at Matauri Bay also have potential.

National websites:

• NZ Minerals Industry Association
• GNS Science