Nacap has successfully completed construction on Origin Energy’s 205 km Wallumbilla to Darling Downs Pipeline. Also known as the Walloons Development Project, the pipeline is a key link between Origin’s Talinga coal seam gas (CSG) Field, located approximately 40 km south of the township of Chinchilla, and the newly constructed Darling Downs Power Station (DDPS), west of Dalby.

Origin’s 630 MW DDPS will be the largest combined-cycle power station in Australia when it begins commercial operations in the first quarter of 2010. It is expected to consume up to 44 PJ/a of gas from CSG fields in Queensland.

The power station is a new generation power plant with gas turbine generators that require significantly less water for cooling than traditional thermal or steam driven power stations. The pipeline also provides Origin with the flexibility to transfer CSG to its developed facilities in the Wallumbilla/Spring Gully area, near Roma in southern Queensland.

Background

Beginning in September 2008, Nacap mobilised to the Darling Downs region to construct the 18 inch steel pipeline. Success of the project initially hinged on Nacap’s ability to commence site works in early October 2008. The challenge was twofold as the construction window coincided with the seasonal rainfall period in the region. Nacap called on the experience of its Project Manager Ben Rees to drive the rapid mobilisation of the project.

Nacap has recently established a permanent presence in Queensland with the opening of an office in south Brisbane catering for the strong growth of the CSG industry along with other pipeline opportunities in the state.

The construction process, subcontractors and equipment

Mainline activities commenced with survey, clear and grade in mid-October. As an omen of things to come, early rain slowed progress but didn’t dampen the enthusiasm to keep the rate of progress high. To achieve the practical completion date, each activity needed to be meticulously planned and executed. The program for completion provided little float and this was soon absorbed by poor weather conditions which were experienced on three separate occasions.

Nacap, as part of its mobilisation, engaged experienced pipe haulage contractor, Neil Mansell Transport, to transport pipe from the Bredero Shaw factory, located in Kembla Grange, New South Wales to the right-of-way (RoW). Logistical flexibility played a major role in the early success of this project and as a result, multiple modes of transport were employed. Transport included direct truck transport to the RoW, truck transport to pipe stockpile at North Star near the New South Wales/Queensland border and rail transport to North Star with truck transport to the RoW from the stockpile. Dedicated transport management ensured that pipe arrived onsite in the quantities required by the stringing schedule.

The construction of the Wallumbilla to Darling Downs Pipeline came hot on the heels of Nacap’s construction of the Epic Energy’s QSN Link Project with a large number of people and plant immediately available for mobilisation to begin the project. With the large fleet of plant arriving onsite to commence construction, there was a requirement to have all machinery certified ‘weed free’. This process involved a significant number of people employed to wash down machinery in readiness for inspection, demonstrating a commitment to positive environmental outcomes and sustainability.

Machinery used on the project came from a variety of sources including Nacap’s own trenching, welding, coating and padding equipment bolstered by trenching, general transport, light vehicles and earthmoving machinery provided by suppliers and sub-contractors with whom Nacap previously had successful relationships.

Early in the project, Nacap utilised the Ausco camp, located in Chinchilla. Project progress and pipeline length necessitated the rapid establishment of a second camp closer to Roma. A suitable site was located on the Warrego Highway near Yuleba, approximately 60 km east of Roma. Nacap was constrained to developing the campsite on a travelling stock route. The camp, built to house 200 workers, was fully operational by the beginning of December 2008 including all the comforts of home and a few extras. Catering constantly met the challenge of fluctuating numbers in and out of the camp along with special events, including an Australia Day barbeque that will long be remembered for some dubious cricket performances and a terrific spit roast dinner.

There were three horizontal directional drilling (HDD) crossings on the project. This specialist activity was undertaken by Pipeline Drillers. Challenges during this operation included variable ‘down hole’ conditions, equipment failures and tight timeframes to be met in order to achieve hydrotest requirements. Successful completion of the last HDD pullback was achieved in mid-January 2009 when the pipe string under the Condamine River was installed.

Delivery obligations were such that a rapid deployment of resources was necessary. At the peak of mainline activities, the welding crew achieved a consistent rate of 4 km per day followed by a fast finishing joint coating crew. The lowering in plus bed, pad and backfill crews were significantly hindered by poor weather, particularly during the last weeks of the mainline operations, when a 200 mm deluge of rain fell in one night, localised over the western end of the project site.

Health and safety

Vehicle travel was the greatest single safety risk on the project. In a deliberate focus on driving behaviours, including risk assessment of designated drivers, Nacap’s crews travelled well in excess of 4 million kilometres on the project without a single lost time injury (LTI). Even more pleasing, in excess of 320,000 man hours were worked with no LTIs sustained. The zero LTI result replicated the safety performance on the 182 km QSN Link Pipeline.

Nacap’s Corporate Health, Safety and Environment Manager Tony Vervest said “The major contributing factor to this outstanding safety performance has been the continuing process of implementing Nacap’s proven health and safety management systems, particularly the Fitness for Work policy and the behavioural-based program ‘Time Out For Safety’. This provides positive cultural improvement to ensure the primary objective of ‘do no harm’ is achieved.”

Stakeholders

The route chosen was designed to minimise the impact on landholders and areas with significant cultural heritage and ecological values. For the 105 stakeholders affected due to the construction of the project, Origin and Nacap collectively managed to consult and communicate the specific implications to the landowners prior and during the construction process. Furthermore, they ensured that commitments were understood, achievable and delivered. The measure of the project’s success was the fact that not one single complaint was received.

Both affected traditional owner groups, the Barunggam and Mandandanji, were actively involved in the initial consultation process, ensuring that locations of cultural importance and management measures were established at these significant locations. Both groups were integrated members of the construction delivery team, ensuring compliance with the cultural heritage management plan and providing inspection and monitoring during certain parts of the clear and grade process, in the event of discovering further locations of cultural importance.

Personnel and the project challenges

Key roles on the project were filled early, including James Povey as Construction Manager. Rod Davis was the Construction Superintendent, whose experience on pipeline projects over many years was clearly demonstrated with his pre-construction review of the entire alignment, yielding positive outcomes and early initial contact with some local landowners. Andrew Ginns was the Lands, Environment and Cultural Heritage Manager and was responsible for delivering the project to a high standard with no environmental incidents or landowner complaints. He provided a sound working relationship with the two traditional owner groups.

The variability of soils saw Nacap’s ditching crew employ a range of machines including excavators, rock breakers, bucket wheel trenchers and three chain trenching machines. A significant challenge along the pipeline route was the presence of black soil compounded by wet weather conditions hampering trenching progress. Responsibility for the performance of the Plant Department was handled by Ross Demby ranging from the upkeep of light vehicles through to maintenance of high wear items such as the padding machines, trenching machines, welding and coating rigs. The Plant Department’s responsibility for such a large fleet necessitated a large crew of diesel fitters, electricians and utility welders.

Work on the project was conducted under Nacap’s ‘total quality management’ framework, developing comprehensive project plans to incorporate Origin’s requirements for safety, quality and environment. Assisting Nacap Quality Manager Nic Fusca was pipeline quality expert Mike Hennessey. Throughout the life of the project, Nacap’s robust systems were constantly shown to be of a high standard from pre-construction work through to the final hydrotest.

Environmental performance on the project was supported by the employment of four specialists in lands, environment and cultural heritage matters. Nacap engaged two fauna handlers Steve Wilson and Gerry Swan for wildlife management on the project.

Safety performance on the project was a paramount concern for both Nacap and Origin. Nacap employed Safety Manager Tony Green plus two safety officers, Adrian Barendsen and Terry Hooper, along with Paramedic Katherine MacArthur for the duration of mainline activities. Origin Project Safety Advisor Ron Freidrichsen worked closely with Nacap monitoring key safety lead items such as worker safety behaviour on the project.

One of the more challenging aspects of the project was the pipeline alignment interacting with many third party assets including major roads, CSG flowlines and major gas supply lines, such as the Roma to Brisbane Pipeline. Work around these assets necessitated Nacap’s close involvement with approval authorities to ensure a clear understanding of their individual requirements. Crossing approvals included pipeline separation distances, reinstatement requirements and construction methodologies.

Included in Nacap’s scope was the construction of mainline and offtake facilities. Three mainline valves were installed along the line along with a number of offtakes to take advantage of CSG fields being developed by Origin and other proponents in the region. These offtakes provide further flexibility to draw gas from and provide gas to other markets in the region.

Hydrotesting of the pipeline followed a tight schedule to ensure that the line would be available for Origin to commission in early April 2009. Hydrotesting was broken into multiple sections and tests began at the DDPS end of the project and worked west. Testing was completed mid-March 2009 with a number of hurdles overcome, including tight timeframes and the need to work on a night-shift basis in order to achieve the practical completion.

Landowner access to the RoW along the entire pipeline alignment required a vast range of approaches as the land use pattern varied from small block holdings with weekender accommodation to large properties running premium cattle herds and crops. Nacap’s Lands Environment and Cultural Heritage Manager worked with the Origin representative to obtain clearance for works to commence as well as conducting pre-rehabilitation and final reinstatement meetings with landowners. The project enjoyed strong relationships with local stakeholders and the community both directly and indirectly involved in the project.

A team of engineers worked on the project ensuring that the vast number of technical issues arising from construction activities were dealt with and closed out. Nacap’s engineering team, led by Luke Baldock, undertook a range of different tasks from managing the installation of facilities to management of surveyors and pipe haulage logistics. Facilities and testing commenced in January 2009 and were successfully completed in April 2009, along with the review and handover of the necessary documentation to permit operation of the pipeline system.

One particularly challenging part of the project was the resourcing of suitably skilled labour due to other competing projects. Effective assessment and training programs were implemented to ensure the personnel deployed were suited to the task performed.

Sustainability and delivery

The successful delivery of the Wallumbilla to Darling Downs Pipeline improved outcomes for the employees, stakeholders and communities and demonstrated the commitment of Origin and Nacap to work collaboratively to ensure sustainable outcomes. Nacap overcame a series of physical challenges mainly presented by adverse weather and was able to demonstrate its ability to provide resources at key pressure points during the construction process, thus delivering a timely and sustainable outcome.