Onekaka Ironworks Quarries and Hydro-electric Power Scheme

Takaka-Collingwood Highway (State Highway 60), ONEKAKA, Golden Bay/Mohua, Tasman

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Parapara maunga, the iron-oxide ores it contains, and its rivers, are culturally significant to the tangata whenua of Te Tau Ihu, including hau kāinga Ngāti Tama ki Te Tau Ihu, Ngāti Rārua and Te Ātiawa o Te Waka-a-Māui. The Onekaka Ironworks Quarries and Hydro-electric Power Scheme, built in 1922 and 1929, has historical, technological, and archaeological significance as a physical link to an ambitious iron mining and smelting scheme. Although this undertaking ultimately proved uneconomic, the remains of the scheme’s infrastructure are a rare physical reminder of its impact on the locality. People have inhabited Mohua (Golden Bay) for many centuries, valuing its climate and resources, including kōkōwai (red ochre), obtained from the foothills of Parapara, a maunga of great cultural importance to tangata whenua. The mineral richness of the Onekaka-Parapara hills was also recognised by early colonists, who moved quickly to secure this resource for the Crown. The Onakaka Iron and Steel Company was formed in 1920, consolidating various earlier mining leases that had not been fully realised. Forty men were employed to construct smelting works on a terrace to the west of State Highway 60. The plant was fully operational by 1924, producing bars of pig iron suitable for making railway irons, stoves and pipes. The company infrastructure stretched from the hills to the coast at the Onekaka Inlet. Limonite (iron ore) and limestone was obtained from adjacent open-cast pits in the foothills; workers lived on site in huts. Then an aerial ropeway carried buckets 2.4 kilometres downhill to the ironworks. The raw materials were crushed, washed, mixed with coke produced on site, and smelted in a blast furnace. Good transport routes were necessary to get machinery and coal to the works, and the smelted iron products from there to domestic and international markets. A wharf was constructed at Onekaka Inlet and a tramline ran 2.6 kilometres directly from the wharf to the ironworks. In 1928-29, near to the quarries, a hydro-electric scheme consisting of a 10-metre-high concrete arch dam on the Onekaka River, a 1.25-kilometre-long penstock, and a powerhouse containing a Boving Pelton wheel, was built to power the ironworks’ new pipe-making plant. The ironworks were a major employer in the area, and with over 81,000 tons of iron produced between 1922 and 1935, hopes were high for an enduring industry. However, ultimately the enterprise proved uneconomic, and the company was placed into receivership in 1931 before closure in 1935. Government efforts to revive the Onekaka industry ceased in 1954. The ironworks were dismantled, and bush reclaimed the quarries and the workers’ camp. However, the hydro-electric power scheme continued to be useful. The Golden Bay Electric Power Board utilised it to meet increased demand from 1937 until the Cobb Hydro-Scheme could supply all the load. In 2003 the dam gained a new lease of life when it was resurrected by Onekaka Energy Company Ltd, and it continues to supply power to the national grid.

Onekaka Ironworks Quarries and Hydro-electric Power Scheme, Onekaka. Onekaka Dam | Blyss Wagstaff | 27/01/2021 | Heritage New Zealand
Onekaka Ironworks Quarries and Hydro-electric Power Scheme, Onekaka. Fallen aerial ropeway buckets | Blyss Wagstaff | 27/01/2021 | Heritage New Zealand
Onekaka Ironworks Quarries and Hydro-electric Power Scheme, Onekaka. An aerial ropeway tower | Blyss Wagstaff | 27/01/2021 | Heritage New Zealand

Location

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List Entry Information

Overview

Detailed List Entry

Status

Listed

List Entry Status

Historic Place Category 2

Access

Private/No Public Access

List Number

5120

Date Entered

12th December 2021

Date of Effect

1st January 2022

City/District Council

Tasman District

Region

Tasman Region

Extent of List Entry

Extent includes part of the land described as Pt Sec 19 SO 15200 (RT 212069; Kahurangi National Park NZ Gazette 1996 p.977), part of the land described as Sec 1 SO 15230 (Conservation Purposes NZ Gazette 1995 p.2242), part of the land described as Lot 2 DP 19322 (RT NL12C/1283), part of the land described as Sec 1 SO 15235 (RT 131389) and part of the land described as Lot 1 DP 331995 (RT 131389), and the structures associated with Onekaka Ironworks Quarries and Hydro-electric Power Scheme thereon. All land parcels are within the Nelson Land District. Extent includes the limestone quarry and limonite mining sites, associated remnant machinery, workers’ accommodation sites, historic tracks, remains of the aerial ropeway system, and the concrete arch dam, old penstock and powerhouse foundations from the hydro-electric power scheme. The extent does not include the new power station and penstock, or the house or farm buildings on Lot 1 DP 331995. (Refer to map in Appendix 1 of the List entry report for further information).

Legal description

Pt Sec 19 SO 15200 (RT 212069; Kahurangi National Park NZ Gazette 1996 p.977), Sec 1 SO 15230 (Conservation Purposes NZ Gazette 1995 p.2242), Lot 2 DP 19322 (RT NL12C/1283), Sec 1 SO 15235 and Lot 1 DP 331995 (RT 131389), Nelson Land District.

Location Description

Onekaka is 16 kilometres north of Takaka along the Takaka-Collingwood Highway (State Highway 60). GPS information (NZTM): Onekaka Dam: N5485361 E1573642 +/- 5 metres

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