History of Commercial Exploitation
The black sand dunes of the North Island’s west coast were noted by Cook during his initial voyage in 1769. He called the area ‘The Desert Coast’. The first attempts to smelt iron began when Cornishman John Perry stepped ashore in New Plymouth in 1841. He found his attention was immediately drawn to the black sands that stretched along the coast as far as the eye could see. In Cornwall, he had owned an iron foundry, and closer examination of the fine grains showed him that it was magnetic ironsand. His excitement was such that in a letter to his friends in England he said he was ‘astonished to see wealth spread out like a carpet’.
Early smelters in New Plymouth
In 1848, Perry made an attempt to smelt the sand by erecting a small furnace on the banks of a small stream flowing into the Huatoki River. However he struck problems with the fine sand that made its way into the bottom of the furnace before the heat of the fire could reduce it to pig iron. A small quantity of iron was produced and forged into small articles by the local blacksmith.
Development of the industry
During the 1850s and 1860s the provincial government was keen to encourage development of the industry, offering lucrative rewards for any company that could produce good quality iron manufactured from the ironsand. Two companies were formed, bearing the grandiose names of Taranaki Iron Sand Company and the Taranaki Iron and Steel Company. Both suffered financial problems and were unsuccessful.
By 1868, E.M. Smith discovered a new method of preventing the sand from choking the furnace. He mixed the sand with clay to form bricks, which were then heated to high temperatures.
In 1869 a firm from Wellington, Henochsburg and Co, erected a furnace on South Road and attempted to work the sand. The company was expanded and changed its name to the Pioneer Steel Company. Difficulties in making the metal flow freely from the furnace, along with financial problems, eventually saw operations suspended.
Not to be deterred, in 1872 E.M. Smith formed the New Zealand Titanic Steel and Iron Company Ltd. Operations were established at the mouth of Te Henui River.
The works included a blast charcoal furnace and a powerful engine, designed to create immense heat. Nearly four tonnes of iron was produced and made into a variety of items, including two railway wheels cast at Vivian’s foundry in New Plymouth. The quantity of iron produced was not sufficient to keep the company financially viable and the plant was sold and moved to Onehunga.
Throughout the late 19th century, further attempts were made to raise funds to establish iron manufacturing companies. Proposals were even made to utilise crude oil as a cheap source of fuel. In 1889, unsuccessful drilling of an oil well at Moturoa meant no further steps were taken to use oil.
The Heskett process
In 1914, a young mining engineer named John A. Heskett experimented with an idea to process coal and ironsand to produce iron. Known as the Heskett Process, it was used successfully on a small scale by the New Zealand Iron Ore Smelting and Manufacturing Company at Moturoa.
Following WW2, emergent technology, (in the form of the Direct Reduction Kiln and Electric Arc Furnace), was applied by the DSIR and others. In 1959, the Government, using taxpayer money, set up The New Zealand Steel Investigating Company, with the objective of determining the technical and economic feasibility of manufacturing steel using ironsand.
By 1964, following successful trials of the newly developed technology, a process was refined that produced sponge iron from ironsand concentrate, using sub-bituminous Waikato coal as a reductant, and Te Kuiti limestone as a flux.
As a result of technological developments and capabilities, and using the results of the Government’s ground-breaking research, a steel mill was commissioned in 1970 by New Zealand Steel Ltd. It was sited at Glenbrook to utilize the Waikato North Head deposit, sited in the formidable dune on the north side of the Waikato River entrance. This site now produces 150,000 tonnes of steel per year.
Further refinement of the process occurred throughout the 1980s and the construction of expanded production facilities took place in 1986. The current production capacity of the mill is 700,000 t of which 60% is exported.
Land based mining operations were also established at Waipipi (1971) and Taharoa (1972) for export of titanomagnetite concentrate to Japanese steelmakers.
BHP New Zealand Steel Limited produces about 2.4 M tpa of titanomagnetite concentrate, for export and for domestic steel manufacture, from Port Waikato and Taharoa sites. The value of this production is nearly $30M.