Project roll-out began on 1 October 2008 with the mobilisation of management personnel to Perth. Construction commenced in January 2009 and the mainline was complete by January 2010, followed by mechanical completion in April 2010. Completion of the project aligned with all the specified contract milestones required by Dampier Bunbury Pipeline (DBP).
DBP awarded McConnell Dowell Constructors the Dampier to Bunbury Natural Gas Pipeline (DBNGP) Stage 5B Expansion Project in Western Australia, which included a total of 440 km of 26 inch diameter pipeline, looping the existing live DBNGP from Loop 0 near Karratha to Loop 10 east of Bunbury. This was carried out in 11 separate loops, the longest totalling 115 km and the shortest being 21.8 km.
The two initial loops constructed – loops 9 and 10 – were located northeast and south of Perth respectively. Loop 10 in the Pinjarra region was the first loop to commence, closely followed by Loop 9, which ran through the Swan Valley and included both residential and vineyard areas. These loops were chosen as the starting point so that completion would be achieved before the wet season, which typically occurs from April/May in Perth and its surrounds.
Loops 0 through to 8 were constructed in remote locations from Karratha to Dandaragan, and involved crews working from remote base camps. Commencement of these loops was deferred to the beginning of April 2009 to avoid the cyclonic weather conditions that can occur prior to that time in the northwest of Australia. As a precaution against any “˜out of season’ weather, camps servicing loops 0 to 2 were required to be “˜cyclone proof’, with all buildings and equipment anchored down for the duration of their use.
Safety paramount to DBNGP success
On the 23 September 2009, the DBNGP Stage 5B Expansion reached one million man-hours lost time injury (LTI) free, which was a significant milestone for all involved. At project completion, the number of man-hours worked LTI-free would increase in excess of 1.4 million, reflecting the attitude of all employees toward maintaining a safe work environment, and to be “˜home without harm’ everyday.
DBP acknowledged the safety achievements on the project. “One million man-hours without a LTI is a highly significant milestone and underlines the benefits of McConnell Dowell’s Safety Improvement Plan as well as the culture the company fosters, which encourages the significant number of hazard reports being raised by the workforce,” a DBP spokesperson said.
As part of the ongoing initiatives to increase safety awareness, McConnell Dowell, in conjunction with WestNet and DBP, utilised a Vehicle Safety and Speed Monitoring System (VSSMS). The VSSMS was installed on all project vehicles to create an environment of driver safety awareness and to improve road safety performance across the project. The VSSMS was used to monitor and improve compliance on the project by tracking the following:
- Exceeding the speed limit in zoned areas;
- Deviation from nominated route;
- Vehicle break down; and,
- Activation of the panic alarm.
A concentrated effort enabled McConnell Dowell to achieve a total in excess of 4.5 million kilometres driven without major road incident on the project. The recording of employee, travel and location details between different loops on the project, in accordance with a journey management procedure, enabled a tight rein on the whereabouts of personnel in remote areas. With the added security of the VSSMS trackers, employees were able to travel in remote and often isolated areas with the secure knowledge that they were always in contact with assistance should it be necessary.
A welcome supplement for driver safety was the installation of a panic button for use in the case of an emergency. The panic button can be pressed at any time, alerting the VSSMS controller with the location of the emergency, enabling a rescue team and/or medical assistance to be dispatched in conjunction with confirmation of the situation.
The inclusion of a “˜drowsy driver’ detection system into pipe haulage trucks and long distance heavy transport vehicles was another safety innovation employed by McConnell Dowell in conjunction with WestNet and DBP.
Auditing of the project safety and environment performance for compliance to the regulatory and project-committed undertakings was a continual process throughout the project. An audit score in excess of 85 per cent was maintained throughout, which further demonstrated the safety focus and committed nature of the entire project team.
The prime emphasis throughout the construction was to ensure a safe work environment in conjunction with a safe work approach from all employees. The final outcome demonstrated that this was achieved.
Meeting the challenge
Construction of all loops required close liaison with project stakeholders including landowners, affected residents, government agencies, local councils and shires, local indigenous leaders, and other affected parties. Particularly close liaison was maintained with the local fire authorities as the project moved through each Shire. McConnell Dowell assisted these authorities controlling fire outbreaks on numerous occasions during the construction of loops 7, 8 and 10. Generally, fire outbreaks were caused by natural occurrences such as lightening strikes or inclement conditions, and were responded to urgently and effectively.
Liaison with stakeholders was of particular importance during the construction of Loop 9, especially through what was known as Pipeline Park in the Ellenbrook Estate. This portion of the pipeline traversed an established community park and recreation area. Recognising the importance of community acceptance, a Community Liaison Officer and information van was established within the park environs to address questions and concerns in relation to the construction activities and progress. This proved to be worthwhile receiving plenty of positive community feedback.
During the project numerous large river crossings were completed by horizontal directional drilling (HDD), open cut conventional installation, and open cut float-in installation methodologies. These included a 360 m wide float-in installation across the Maitland River, a 126 m wide float-in installation across the Yanyare River on Loop 0, and a 300 m HDD crossing of the Murray River on Loop 10.
Numerous trenchless crossings were required throughout the project. These encompassed roads affected by heavy traffic and major routes including Highway 1, located south of Karratha, which was crossed in three separate locations on Loop 0. A large number of trenchless crossings were also completed in loops 9 and 10 where traffic and public access was the main catalyst for this requirement. Rail lines were also crossed using trenchless technology.
The logistics involved with continually moving campsites and personnel presented one of the greatest challenges on the project. The movement of personnel in and out of work locations for rostered cycle breaks was also a challenging exercise. This was successfully handled on a continual basis using both domestic and chartered flight facilities. Other challenges included extreme weather conditions, with onsite temperatures sometimes reaching over 50 degrees Celsius and dropping as low as -5 degrees Celsius, and the geological conditions associated with the arid areas of Western Australia.
An emphasis on zero environmental loss of either flora or fauna meant that the environmental team had a huge challenge, especially where the potential loss in open trenches could be catastrophic if not properly inspected and managed. To this end, McConnell Dowell followed strict inspection regimes, ensuring that all project responsibilities were met. In the case of flora protection, the McConnell Dowell environmental team located and ensured that protected species, additional to those previously flagged, were identified and protected from the construction operations. As noted earlier, the success of these efforts by environmental personnel were conveyed by the results of the external audits.
Following the successful completion of the DBNGP Stage 5B Looping Project, McConnell Dowell has laid over 30,000km of pipelines, and completed over 100 km of HDD and tunnelling installations in all geological formations.