The Burdekin water pipeline is a critical infrastructure link for the development of 6 new coal mines within the Bowen Basin, in the Moranbah region.

This article – which summarises the recent presentation by Leon Richards, Project Manager on the Burdekin pipeline and Construction Manager on the Western Pipeline Alliance (WPA) and Chris Swaine, Southern Regional Water Pipeline (SRWP) Alliance Pipelines Project Manager, at the 2007 APIA Annual Convention – presents project details by importantly highlighting the cross country pipeline techniques utilised in the construction of the water pipeline. These include dedicated crews for all activities, and the construction of a Right of Way (ROW) with a defined ‘running track’ to allow efficient haulage of pipe and sand bedding.

In respect of the environment, the project continued with the same techniques and personnel in managing the flora and fauna on the North Queensland Gas Pipeline project.

In addition to the Burdekin pipeline, cross country pipeline techniques are being utilised on two other McConnell Dowell water projects in southeast Queensland – the $900 million SRWP, connecting Mt Crosby in Brisbane to Molendinar on the Gold Coast; and the WPA, which is constructing the Bundamba to Caboonbah section of the Western Corridor Recycled Water (WCRW) Project.

Burdekin to Moranbah Pipeline Project Background

The substantial growth in world demand for Queensland coking coal has seen a number of coal mine developments in the Bowen Basin in recent times. Successive years of well below average rainfalls had left the Eungella Dam at critically low levels, threatening the region’s mines which rely on it for their essential water supply.

The project had a critical timeframe applied by the low level of the Eungella Dam. Without significant inflows into the existing local storages such as Eungella Dam or the Gattonvale Offstream Storage, water supplies to existing mines were severely limited. The project supplements the existing water supplies drawn from these sources in the event that repeated future wet seasons fail to replenish dam levels; and it will also enable the Queensland coal mining industry to better plan for future expansion.

The State Government declared the pipeline as ‘works’ under the State Development and Public Works Organisation Act 1971, so that they could use relevant powers, if needed, to make sure the project was finished on time. These powers relate to land access and acquisition, opening and closing of roads, environmental coordination and access to construction materials.

Water is used in these mines for key mining activities such as onsite handling, processing and dust suppression. Without a definitive water source available, this makes these operations very difficult.

Project details

The 217 km long pipeline crosses 40 km of freehold land, with the remaining tenure being held by the State. The route begins at Gorge Weir downstream of the Burdekin Falls Dam and joins the North Queensland Gas Pipeline route, before cutting east to join the route of the existing Eungella Pipeline to Moranbah.

The pipeline design provides for the capacity to deliver 16,800 ML per annum to a terminal storage at Moranbah. This capacity includes 200ML for stock and domestic supply en-route to landholders providing easements, and for pipeline operational losses.

The major infrastructure for the project included:

* A pump station at Gorge Weir and upgrade of the existing weir structure; * 217 km of pipe from Gorge Weir to Moranbah; * A 600 ML balancing storage dam, located 35 km north of Moranbah, providing the major storage in the pipeline for supply continuity; * Three booster pump stations; and, * A small 5 ML terminal storage at Moranbah with the capability to interconnect to the existing 200 ML Moranbah Terminal Storage at the terminus of the Eungella Pipeline.

Construction

A 220 person camp was constructed approximately 10 km from Collinsville to house the majority of the workforce. To ensure minimal impact on the environment, the previous construction camp site used during the North Queensland Gas Pipeline Project was utilised.

Daily production rates were achieved similar to those expected on a typical cross country gas pipeline. Such production rates were achievable by ensuring that the ROW and materials were strung out along a 30 m wide ROW of a sufficient standard, well in advance of the proceeding pipe laying crew.

Production crews per activity such as ROW preparation, pipe stockpiling and stringing, trenching, pipelaying and backfill, ensured that a good rate of progress was achieved.

Rates of progress achieved included an average of 1.25 km of pipe in the ground each day, with a peak daily installation rate of 3,100 m of pipe laid in a single day – an Australian water pipeline laying record.

In excess of 4 million km was driven by project vehicles, which included a fleet of twenty-five truck and trailers that were used to haul approximately 350,000 m³ of sand extracted from the Bowen, Suttor and Isaac Rivers.

An Environmental Management and Fauna Capture program was successfully implemented on the project. The smallest marsupial encountered was an Ingram’s Planigale which is the smallest of the marsupials, with a body of only 6.5 cm in length. The benefits of fauna monitoring included: rescuing wildlife from trenches; removing and relocating dangerous animals from the workplace; and adding scientific records to the state’s fauna data-base.

Western Pipeline Alliance (WPA)

Background

Southeast Queensland (SEQ) is Australia’s fastest growing metropolitan region and this strong growth is set to continue, with the population projected to reach 3.7 million people by 2026.

A crucial part of planning for SEQ’s future growth and development is effectively managing the region’s water resources. A secure water supply is essential for achieving sustained growth, while also maintaining quality of life. The current drought, the worst on record, has highlighted the vulnerability of SEQ’s existing water sources. The WCRW Project is one of a number of Queensland Government initiatives in response to the drought conditions and the ongoing need for a more secure, climate-independent water supply for SEQ.

Project Details

The $2.4 billion WCRW Project is the largest recycled water scheme in the Southern Hemisphere and employs the latest water filtration technology and expertise from Australia and overseas.

By mid-2008, the Swanbank and Tarong power stations will receive up to 66 ML/day from the Bundamba Advanced Water Treatment Plant.

When completed by the end of 2008, the WCRW Project will link existing wastewater treatment plants at Oxley, Wacol, Goodna, Bundamba, Luggage Point and Gibson Island to advanced water treatment plants at Luggage Point, Gibson Island and Bundamba, then connect to the Wivenhoe Dam.

These plants combined will provide up to 232 ML of purified recycled water to power stations and Wivenhoe Dam each day via approximately 200 km of buried pipelines, of up to 1.5 m in diameter.

The WPA, consisting of the McConnell Dowell AbiGroup Joint Venture as constructor, GHD as designer and the Queensland Coordinator General, is constructing pipelines between Bundamba and Caboonbah, where the pipe is tied into the Tarong Power Station’s existing water supply system.

Construction

A substantial section of the pipeline is constructed within the Wivenhoe Catchment, which supplies the greater population of Brisbane with its drinking water supply. As a result, state of the art environmental sedimentation and erosion control devices were installed along the ROW during the construction.

Innovative construction techniques and equipment were utilised on the 1,000 mm diameter Glass Reinforced Polymer (GRP) pipe. These included the design and implementation of a mobile trench shield and a GRP coupling press. These value saving devices also assisted in increased pipeline installation rates.

The project is an ‘Extreme Fast Track’ pipeline project, with the Environmental and Social Impact Assessment (ESIA) submitted for public review in December 2006 and construction starting in early March 2007, following the completion of the public reviewing period of the ESIA which finished in late February 2007.

Numerous stakeholders were involved in the project, such as SEQ Water, Esk Shire Council, Ipswich Shire Council and numerous local community groups.

The mammoth 1,451 mm diameter Mild Steel Cement Lined (MSCL) pipes were supplied by Tyco Water in 13.3 m lengths. These individual pipes weigh some 7.5 tonnes each and require the use of large 75.t – 85.t excavators to string and lay the pipe in the large trenches.

A 40 m wide ROW assisted in the ability to install a maximum single day installation record of 1,200 m of 1,000 mm diameter GRP pipeline. Similar methods to those used on the Burdekin to Moranbah pipeline project were adopted to achieve these installation rates.

Background

The Southern Regional Water Pipeline (SRWP) is a vital piece of regional infrastructure that will provide a bulk fresh water supply network between Brisbane and the Gold Coast.

The pipe’s reverse flow capacity will enable 130 ML of potable water, from existing and future water sources, to be moved where it is most needed for residential and commercial development in Brisbane, Ipswich, Logan, Beaudesert and the Gold Coast.

The SRWP is approximately 95 km long, connecting to Brisbane’s water supply at Mt Crosby in the North, to the Gold Coast’s water supply at the Molendinar treatment plant in the south.

The $900 million project was granted Significant Project status by the Queensland government in September 2005 as a fundamental part of the Queensland Government’s drought strategy initiative.

Construction is being undertaken by the SRWP Alliance, consisting of the McConnell Dowell AbiGroup joint venture as constructor, KBR as designer and LinkWater.

The Alliance began earthworks for the main project office in Bundamba in September 2006. Construction of the pipeline and related infrastructure started in October 2006.

Project Details

The SRWP traverses a number of different terrains, from highly sensitive mapped vegetation requiring significantly restricted easements, through 276 private properties, to highly residential urban landscapes.

The SRWP is made up of the following components;

* 95 km of MSCL pipeline ranging from 1,290 mm OD to 960 mm OD; * 4 balance tanks of capacity 25 ML to 30 ML; * 5 pumping stations; * 6 elevated structures (pipe bridges); * 8 pigging stations; and * 12 section valves and offtakes.

Construction

A unique part of the construction of the SRWP was the bored crossings. The SRWP purchased a Herrenknecht AVN1500 Tunnel Boring Machine (TBM) and associated plant for the large number of drives on the project, in addition a second TBM was been hired from Herrenknecht for the work in Area 38: Wet and Wild to the Molendinar Balance Tanks. All the TBM works are self performed using key McConnell Dowell staff.

There were nine crossings selected for the TBMs, including four rivers with significant temporary works using secant piles for the shafts to a depth of 30 m in places. The jacking shafts are 8.5 m in diameter and the receiving shafts are 6 m in diameter. The depths are required to tunnel through optimum ground conditions ranging from soft sandstones to 200 MPa greywackes. The tunnel drives range in length from 130 m to 550 m, under geographical features such as rivers, motorways and through steep hillsides.

The majority of the pipeline alignment traversed public roads, requiring small pipe installation crews conducting the dig, lay and bury at approximately three to four pipe lengths a day. Installation of the pipeline was a combination of styles, involving street works with rapid reinstatement in close proximity, to avoid disturbance to the landholders and general public.

The key to success on these work fronts was to integrate traffic management with the upfront location of services and then the reinstatement of pavement and vegetation following pipeline installation.

Where conventional ROW could not be constructed, a running track allowing access for pipe was required to string and weld pipe and further stockpile of the 5 - 7 mm bedding sand required for the backfilling around the pipe.

Increased productivity was achieved by the using vacuum lifts, fitted to excavators during stringing and where possible, the welding of fittings (such as bends, air and scour valve spools) onto the pipes.

An innovative approach was used with the excavation of rock in urban areas. Drill rigs were used to drill 89 mm diameter holes, 150 mm below the invert of pipeline, on either side of the trench centreline. This then facilitated easier excavation, as the holes created a plain of weakness in the 200 MPa greywacke.

Further innovations adopted included the use of GPS/GLONASS survey machine control used by the field survey team for most survey tasks, including eleven machine control units mounted on excavators and dozers.

The geographic locations of the base and repeater stations are in close proximity to the pipeline alignment, at elevated positions, providing coverage of 7 km with an overlap of approximately 1 km.

The use of this technology enabled consistency in design of the alignment line and level being established in the field; elimination of multi-instrument setups each day; flexibility in logistical programming of plant movements; fewer pipe laying crew members; reduction in human error in determining measured depths; and elimination of the need for re-staking.

A further innovative concept that was investigated included the trialling of a CRC Evans 32 inch to 42 inch pipe bending machine for the cold bending of 13.2 m pipes on the 960 mm OD Orrcon supplied MSEL water pipeline. The bending operation was successful with the use of an internal mandrel for every pipe bend; use of a lined die; and, a 1,200 PSI hydraulic system operation pressure. This resulted in a maximum allowable bend angle of 1.5 degrees per diameter with tangent lengths of 2.7 m and 4 m from pipe ends.

Conclusion

The above three projects illustrate McConnell Dowell’s recent involvement on major water pipeline infrastructure projects, all being delivered through alliancing frameworks.

McConnell Dowell have to date achieved success on these challenging projects, through the implementation of creative construction techniques to aid in providing value and ensuring a timely delivery of project objectives.