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Nelson Historical Society Journal, Volume 3, Issue 5, October 1979

Pipe Making

Pipe Making

The plant which was installed for making the cast iron pipes made use of the upright process with a greasy core and mould as this was the usual process until that time. Mr N. P. Livingston, now living in retirement, was appointed chief engineer at the works in 1929, and he had charge of the building of the pipe foundry. Five casters were employed and everything was moulded on the site. To make pipes by the vertical process the mould was set on a kellett plate at the bottom while central core was covered with loam, a mixture of fireclay. The moulds were 12 feet (3.68 m) long and a 24 inch pipe (.61 m) pipe weighed one ton. Three men were brought from England as pipe making experts but on arrival it was found that they knew their particular jobs but did not have the technical knowledge which the company required. The plant was ready to proceed but to overcome the teething problems it was necessary to get a good man over from Australia. At first all iron for casting was melted in the foundry by cupola but afterwards it was found satisfactory to transport molten metal direct from the blast furnace in a cupola on a truck line. To make good pipes everything had to be just right, the mixture, heat, and everything else. Twenty vertical gas retorts were used as the moulds had to be warmed by a hot box which was fired all night in readiness for daytime page 20production. The finishedpipes were loaded on to rails with a slight incline so that they moved down by gravitation, and the ends were trimmed at top to remove the riser where the metal had been poured in.

Onakaka pipes were turned out according to the British Standard Specification for Cast Iron Pipes and Special Castings for Water, Gas and Sewerage. As the pipes passed through a building where they were hydraulically tested for pressure they were hit with a hammer and some cracked. Standard hydraulic pressures which were required were 200 lbs (91 kg) per square inch (25 mm) for gas pipes and 400 to 800 lbs (181 kg to 362 kg) for water pipes according to the required purpose and grading. A 61b (2.7 kg) hammer was used to locate any weak spots and reject pipes were crushed and sent back for re-smelting. Pipes were warmed and then dipped in warm tar and drained. The Auckland City Council and the New Plymouth City
Cast Pipes passing throgh Cutting and Testing Sheds. Engineer's house on left – (M. P. Livingston)

Cast Pipes passing throgh Cutting and Testing Sheds. Engineer's house on left – (M. P. Livingston)

Council each bought pipes for underground use in the sizes of 24, 12, 9 and 4 inches (609, 304, 228 and 101.6 mm) for mains and leaders and it is believed that these are still in use. Certainly the ones bought by the Nelson City Council in 1930 to the value of 624 pounds ($1248) in 1934 still are. Well made cast iron pipes will last indefinitely but cast iron cannot be heated and worked like steel as it would disintegrate. If made from reclaimed iron and steel it would have weak places in it.

Slumptime conditions soon brought problems. The Australian works commenced making lighter pipes by a horizontal spun process and undercut the price for cast pipes as well as for pig-iron. The Onakaka Company went into receivership in 1931 but the manager, J. A. Heskett, took up the contract to manufacture pipes and pig-iron for the receivers. The situation was difficult. It was necessary to compete with the Australians and there was little or no demand for pipes as the local bodies had no funds available during depression years. The plant finally closed in 1935 and further schemes to reopen work at Onekaka did not come to fruition. (Discussion on this subject can only lead to political arguments!) During the Second World War a page 21smelting plant was again established in case it was required for emergency Allied production but fortunately no such crisis arose.

The total production for the operations between 1922 and 1935 was 81,499 long tons of iron, with the production of pig-iron for the period being 41,195 tons, valued at 209,950 pounds ($419,900). This shows about 51 per cent of pure iron.

When the plant was extended for pipe-making a hydro-electric plant was installed to provide power at the works and, although the secondhand pipes which were used in the lead from the dam to the powerhouse sometimes developed leaks, and caused loss of power, the plant was eventually a very reliable generating station. In 1937 the Golden Bay Electric Power Board was operating the plant and continued to do so until Cobb River power became available in 1944.

Pipe Foundry – (Livingston Photo)

Pipe Foundry – (Livingston Photo)

Coal was the biggest factor in the matter of cost of running the works. Wages were not high according to modern standards and the plant could be run with the employment of 30 men although a greater number were there in earlier years. This reduction was possible as the result of the introduction of electric power and other improvements. To give some idea of the undertaking a few details are called for. There were large storage bins for the iron-ore, limestone and coke. Thirty beehive ovens produced the coke and this was red hot when taken out. It was elevated into the storage bin after cooling. The blast furnace was 60 feet (18.3 m) high and had six tuyeres, or pipes through which air is forced into the furnace. The burden to load the furnace was one ton of coke (1.016 tonnes), two and a quarter tons of iron ore, 14 hundredweight of lime (711 kg). This amount was measured into a truck which was then hauled to the furnace top. The furnace was tapped twice daily to produce 40 tons of iron per day. Slag was first run off and allowed to go down a gully. Waste gas from the furnace was heated and used to heat the boilers. There was no firing in the boilers but by no means of a hot air stove, using 24 U-pipes the air was heated to 900 degrees Fahrenheit (342dC) and page 22this prevented pollution by carbon monoxide gas in the works. In the engine room there was a special engine with a 16 foot (4.8 m) flywheel which drove a blower with a 65 feet (19.8 m) displacement per revolution which produced the volume of air that passed through the furnace. There were three watch engineers each working eight hours per day for seven days per week.

Another essential part of the works was the laboratory as a good product could only be produced by application to detail to see that the highest standards were maintained. The manager, J. A. Heskett, was an enthusiast who explored the possibilities of making other products. One of his patents was a process to make basic slag while another was the manufacture of slag wool to be used for packing stoves and hot water cylinders. This was made by blowing air through a line of hot slag. One byproduct from the iron works was oxide of iron (crushed iron ore) which was shipped to Port Nelson for purifying the coal gas which was produced there. (Crushed dolomite from the area was shipped to Huntly by way of the Onekaka wharf for use in lining the furnaces which were used to manufacture basic slag there.)

Cast Pipes ready for shipment. Manager's House in background.– (N. P. Livingston)

Cast Pipes ready for shipment. Manager's House in background.
– (N. P. Livingston)

Prior to the closing of the works in 1935 a great deal of clearing up was done and much of the machinery and equipment which was no longer of use was simply smelted in the furnace. The receivers for the company still maintained control and some machinery continued to be used as required for subsidiary purposes after the closure. Iron ore from Parapara was trucked by McNabbs to Onekaka where it was crushed for oxide of iron to be used for purifying coal gas. This was shipped to most of the gas works in New Zealand except Auckland which was supplied from Kaeo in Northland. The same plant was used for crushing dolomite in the early development of that industry in Golden Bay. The stone was brought down from Mt Burnett by the coalmine ropeway and then trucked to Onekaka.

page 23

The remains of the company wharf are now one of the very few evident signs that this ambitious undertaking ever existed in the area.

The company was beaten by the economic conditions of the time. The League of Nations Disarmament Agreement to curtail production of war materials brought chaotic conditions to industry which had built up during World War I. Large financial combines collapsed, world markets came to an end, and the world was plunged into the Great Depression of the late 1920's and early 1930's. Some countries were anxious to secure markets – even those that gave little return. Had the Onekaka undertaking not had to contend with the extreme conditions which existed at the time it should have made good.

Aerial Ropeway from Quarry – (N.P.M.)

Aerial Ropeway from Quarry – (N.P.M.)