Züblin Australia was awarded the Civil Contractors’ Federation (CCF) Earth Award for 2011 (Western Australia) for their tunnel construction work within the Southern Seawater Desalination Plant. The award was in Category 4 (Project value $20m - $75m). The project required Züblin to construct three HDPE lined tunnels (two intake and one outfall tunnel) beneath the seabed culminating in three wet recoveries of the TBM.

The CCF Awards acknowledged excellence in industry best practice in three major areas. Those being;

	Construction Excellence
	Environmental and Social Management and
	Project Management

The judges acknowledged Züblin’s ability to face challenges in overcoming construction constraints, the use of innovation and creative thinking in design and construction methods and technical complexity when completing the tunnels for the desalination plant. A major challenge faced was the highly variable ground conditions the TBM was required to bore through. This included soft sand, hard rock and at times large voids in the subsea geology. This challenge was met through the use of a Dual Mode Pipe Jacking Machine with a rock cutting head that would suit all conditions and a highly experienced tunnelling team who were able to manage the equipment and conditions admirably.

Technical complexity was evident in the tunnel design with the Client requiring a three dimensional curve spiralling downwards in an ‘S’ format. Use of a cutting edge technology gyro-compass and a highly experienced surveying engineer enabled Züblin to accommodate the Client’s needs and achieve an excellent final product.

Züblin’s Environmental Plan and Environmental Policy has preservation of the environment as a priority, fostering environmental awareness and responsibility in all employees and contractors.

The location of the desalination plant at Binningup, Western Australia was identified as being environmentally sensitive, with several species of endangered or threatened animals making the area their habitat. The construction site was built deep within the natural coastal bushland and was also susceptible to bushfires.

Constant monitoring of water, air, sand dunes, beaches, noise and lighting became an everyday practise on the site. Training ensured all workers were knowledgeable about the potential impact the tunnelling operations could have on the environment and the surrounding community and this was emphasised through further training in spill response, fire response, water contamination, wildlife relocation (including deadly poisonous snakes) and noise management.

The Project Manager (Mr Josef Kofler) and his team constantly achieved project milestones on or ahead of schedule through finely tuning many of the daily work processes, such as;

	Streamlining the pipe lowering process.
	Replacing hand tools with pneumatic tools.
	Improving access and egress of the tunnel through practical placement of utility pipes, and improving the flooring. This had the added bonus of a safety initiative should an emergency situation arise and require extraction of an individual from the tunnel.
	The coupling process was modified when connecting the pipes together.
	TBM operations were adjusted based on experience from the first tunnel.

Overall the project was completed ahead of schedule, well within budget and provided a high quality finished product the Client was extremely happy with.

CCF Earth Awards of Western Australia 2011 – Category 5

A second award was received by Züblin as part of a Joint Venture for the Alkimos Waste Water Treatment Scheme in Category 5 (Project value above $75m). As one of four members of the Alkimos Water Alliance, Züblin was contracted to construct a 6.3km section of sewer with manholes to connect to an existing main sewer to the new Alkimos Wastewater Treatment Facility in the northern suburbs of Perth.

This project also experienced complex and highly variable regional geology with both sand and hard rock. Traditionally these conditions require multiple drill machine changes to compensate for the extremes of each ground condition encountered. Züblin employed their Dual Mode Tunnel Boring Machine allowing them to operate in both Earth Pressure Balance and Slurry modes, changing when the ground conditions necessitated it. The ability to operate in dual mode provided greater flexibility, safety and efficiency during tunnelling operations. This project was completed 3 months ahead of schedule, despite a 4 month delay to the start date.

The construction of such a tunnel meant the nearby residential area was not disturbed to install the pipes and the environmental impact was reduced considerably as no trenches were required as in surface-based pipe laying methods.

Both awards were presented at an Awards Dinner held at the Pan Pacific Hotel, Perth, Western Australia.