Building the Dongara – Pinjarra Gas Pipeline

The Australian Pipeline Trust now owns the Parmelia pipeline, running from Dongara south to Perth and Pinjarra in the south. This pipeline has a long history with construction starting in January 1971 and finishing in October 1971. An interesting article in the first issue of The Australian Pipeliner (March 1972) detailed the construction of this pipeline under the title “How the West Was Won.”

The job involved the building of 258 miles of 14 inch pipeline from Pinjarra, 60 miles south of Perth, to Dongara, about 200 miles north of Perth. It also involved the construction of about 12 miles of 8 inch and 4 inch lateral lines. The purpose was to bring natural gas from the Dongara Gas fields to Perth, the Kwinana Power Station, and Alcoa operations at Kwinana and Pinjarra.

The client was West Australian Natural Gas (WANG), with design and construction management carried out by Bechtel Pacific Corporation. The construction contractor was Saipem Australia. When the contract was awarded in December 1970, Saipem’s equipment was in mothballs in the company’s depots in Adelaide and Melbourne. Saipem had recently completed the Moomba – Adelaide gas pipeline in South Australia and the Longford – Dandenong 30 inch gas pipeline in Victoria.

Looking after the project for Bechtel Pacific were Project Manager Jim Tygret and Chief Inspector Ken de Shan, who later founded East Coast Pipeline and Welding.

The lateral pipelines were sub-contracted to McConnell Dowell, in those days a very small company – in fact, so small they had to borrow a tractor bending shoe from Red Ru in order to bend the 8 inch pipe. The project was managed by Stuart McDonald, with the field work supervised by the late Jim Gubb. The Kwinana Power Station piping work was entrusted to Red Ru Pipeline Construction, who had just completed the construction of a 25 mile Oil Products line for the BP Refinery at Kwinana.

Saipem had some well known names working on the job. The Project Manager was Sergio Maffezzini, Assistant Project Manager was Peter Kerrison, Spread Superintendent was Celio Franceschini, Lands Manager was Don Hamlyn, Maintenance Supervisor was Santo Cantafio, Chief Accountant was Romano Rinaldi and Personnel and Industrial Officer was Ian Tait.

Over the Christmas period and in early January a massive transport operation took place which landed about 2,000 tonnes of plant and equipment in Perth via road, rail and sea.

Construction got underway early in 1971. Progress on the project was good, and all crews finished ahead of schedule. Welding progress was at one time seriously disrupted when the 0.203 inch WT pipe was first encountered. Weld cut outs became very high – the fault being undercut in about 4 inches of the 44 inch circumference – due to overheating of the narrow bevel faces. This was finally overcome by decreasing the heat and power input by using 1/8 inch root run electrodes previously used for slightly heavier wall pipe.

Trenching was the operation that was hardest pressed and forced to work the longest hours to maintain schedule.

An early basic decision was to work north starting from the southern end of the line. The reason for this was to clear the southern 60 miles of the route in summer as this country, although hot and dry in summer, has an uncommonly high water table which is often above ground level in winter. This decision perhaps more than anything else contributed to the success of the job.

Perth rainfall (average 34.79 inches) was about 9 inches behind the average up till the end of August but a very wet September and October brought rainfall up to less than 3 inches behind at the end of October.

Stringing worked from two sea port pipe dumps, one at Fremantle and one at Geraldton. The cartage was subcontracted to Sweeney United Transport.

Trenching averaged 1.41 miles per day utilising two Cleveland 220 ditching machines running in series, continually skipping each other by road transport. Rock areas were blasted and cleared with Poclain backhoes well in front to obviate hold ups of the main crews. Trenching was continually under pressure and had to work seven days a week for most of the period to keep in front of the welding.

River crossings were done with two draglines, 22 RB Rustons, and were separately organised from the ditching operation.

Welding was initially started with one large crew utilising three welders on the root run and two welders on each following run. This method was used for the first 25 miles but this was then altered to two entirely separate crews each utilising two welders on the root runs and teams of two on the remainder runs. The hourly rate for a welder at the start of the job was $2.65, and for a sideboom operator was $1.95.

Each crew comprised 10 to 12 welders with a tracked Paywelder and mobile machines to suit. The crews in general skipped each other once every 24 hours.

Tie-in at road and rail crossings and other crossings used up to five small, lightly equipped welding crews each of two welding qualified for all passes.

The southern 60 miles of line was 100 per cent x-rayed and any welds not strictly in compliance with API 1104 were cut out. The remainder of the line was 10-15 per cent x-rayed.

Welding averaged 1.38 miles per day with the usual day around 310 joints welded. A welding team in the process of delivering 300 welds a day is quite an impressive spectacle.

Hydrostatic testing, involving water treatment and disposal was very closely controlled by all concerned. In particular the West Australian Mines Department witnessed each test and the water disposal technique was approved by WA Government laboratories.

Water was taken from only four rivers for the entire line and it is worthy of note that 143 miles of the line was tested from one river, that being the Moore River which is the only permanent water crossed by the line north of Perth.

There were 20 separate test sections dictated by the land profile and the hoop stress requirement of 100 per cent yield maximum, 90 per cent yield minimum with the majority of the line tested to 95 per cent yield. Minimum actual length of a test section was about 2 miles in hilly country and the maximum done in one test was slightly over 28 miles.

Water was pushed in with two big diesel driven Worthington pumps often running 24 hours a day and two high pressure, low flow, triple piston Wepukos were used for pressurising.

During dewatering multiple cup squeegee pigs were run for up to 28 miles in one run using mobile compressors for motive power and spherical pigs were run for 107 miles in one run using natural gas motive power.

The 300-person camp made three moves being setup in four different locations about 50 to 70 miles apart.

The northern camps had earth formed airstrips for light aircraft which were used quite often, particularly in the Eneabba and Dandaragon areas. The record in planes must have been nine at the Enneabba camp at the ceremony to mark the completion of welding.

Maintenance of equipment and vehicles was a major operation and a major expense. Minor maintenance was done at the camp but anything big was returned to Santo Cantafio at Perth where ten mechanics and two auto electricians with about ten assistants worked six days a week in a workshop to keep the equipment and vehicles running.

The official starting date for the pipeline was 15 January 1971 when clear and grade got underway. Welding started on 5 February 1971 and finished 10 August 1971. Final completion with the finish of test and dewater was 3 October 1971.

The original pipeline is coming up later this year for its 35th birthday. It has played an important part in Western Australia’s development over those years.

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