New standards set15.01.2010 As a replacement for two mills in the urban region of Sydney, Allied Mills Australia Pty Ltd has constructed a new state-of-the-art three-in-one-mill complex on a greenfield site and, in doing so, has set new design and technology standards in the Australian milling industry. Allied Mills is one of Australia’s three large milling groups. Despite the fact that the 60:40 joint venture between GrainCorp and Cargill Australia was “only” founded back in 2002, it has some 200-plus years’ experience in handling grain, thanks to the history of a number of its own milling plants that belong to the group.
The Allied Mills group combines the international milling industry experience of Cargill and the expertise of GrainCorp, both in growing as well as in storing and handling grain. The numerous companies within the Allied Mills group are engaged in the business of milling, grain handling and production and distribution of baking mixes. The customers of Allied Mills include all kinds of flour processors – from small family bakeries through to large international food corporations. The Allied Mills group produces over one million metric tons of grain products each year. In this, they cooperate very closely with Australian farmers and are an integral part within the overall supply chain – from harvesting, handling and storage, grinding and blending to delivery to their customers.
Heading out of the city
One of the largest mills of Allied Mills group is located – or rather was located – in Summer Hill, a district of Sydney with a population of 3.7 million, Australia’s largest city. Founded in 1788, the capital city of the federal state of New South Wales hosted the Olympic Games in 2000.
The location of Allied Mills in the district of Summer Hill would have made the planned extension and modernization at the old site unnecessarily difficult and also more expensive. What is more, being located in an urban area also imposed additional regulations that pushed up costs. “For this reason, we decided to relocate our mill away from the city to a greenfield site,” explains David Ambrose, the National Technical Manager of Allied Mills. “This gave us the opportunity to construct an entirely new three-inone- mill complex featuring state-of-the-art milling technology. Besides reducing our operating costs, the new mill also allows us to decommission two aging facilities.” The location chosen for building the new mill complex was a large site in Picton, an outer suburb situated to the southwest of Sydney, in the immediate vicinity of the Sydney-Canberra railroad line and next to the southwest freeway.
Buhler as a partner
Planning of the new three-in-one-mill complex with an investment volume of around 90 million Swiss francs got underway in 2004. As the supplier of the entire mechanical equipment for the three new mills, including wheat storage facilities, the flour silo, the blending plant and the bulk outloading station, Allied Mills also opted for technology co-operation with Buhler. “The partnership between Cargill and Buhler has been proven worldwide,” says David Ambrose, justifying the choice of Buhler as its technology partner. “What is more, we know Buhler as a supplier of milling equipment and entire milling plants in Australia. And finally, by working together with Buhler, we were also looking to receive particularly energy-efficient solutions.” The new mill project of Allied Mills was the first full greenfield project to be realized in New South Wales for almost 50 years.
Moment of shock
The building constructors experienced a moment of shock in the planning phase. During the mandatory archaeological inspection of the building site, a number of Aboriginal artifacts of historical significance were found. This meant having to move the entire mill complex some 30 meters. However, this did not prevent the local planning and construction firms from completing the preliminary work on schedule.
When the Buhler engineers arrived on site to start their work in January 2008, the mill complex with its 18 large wheat cells was ready. The mill complex was constructed by the slip-form method, which was a first for Australia. This method is used especially for high, tower-shaped buildings and for long protective concrete walls. With the slip-form method, the slip forms are continuously pushed upwards in the course of construction work. During this process, it is important to ensure that the concrete will set as the forms slide. Unlike climbing forms, the slip-form method requires 24-hour shift operation until completed.
Three mills in one
The basic planning of the new milling plant was done in close collaboration with the customer. The objective was to create a total milling capacity of 200,000 metric tons of wheat and maize (corn) per year. Detail engineering produced three state-of-the-art mills in one single building complex.
The process chain starts with the joint grain collecting station, which then moves the material along to the weighing and pre-cleaning sections and onward to the storage facility. Following a second cleaning stage, Mill A is used for grinding hard bread wheat. Mill B is also equipped with its own cleaning section and grinds semi-hard and bread wheat. The third mill – Mill C – is also equipped with its own cleaning system and is dedicated to the processing of maize/corn.
Various special features
Extra consideration was given in the design to the layout of the new threein- one-mill complex with a number of special energy efficiency features. In addition to the efficient layout, the pneumatic conveyor fans of all three mills are equipped with frequency converters and self-optimizing controls, which help achieve additional significant energy savings.
Last, not least, inside the corn mill, the Buhler Sortex color sorter sorts the corn grits before the actual grinding process. The wheat is also cleaned with the aid of a Buhler Sortex unit prior to grinding in the mill. Downstream of the milling section, the various types of flour enter the 18 large flour silos. This stage is finally followed by the flour discharge station and continuous blending with various additives depending on the particular recipe. Immediately before the bulk outloading station, a final control sifting stage is also carried out.
Grand opening on March 31, 2009
Just ten months after the start of installation, Mill A was commissioned in mid-November 2008. Mills B and C followed shortly afterwards and were completed before Christmas. Since then, the three mills have all been running reliably and to the complete satisfaction of the customer. “Our expectations regarding energy savings have also been fully realized,” confirms David Ambrose.
On March 31, 2009, the grand opening of the new three-in-one mill complex took place in Picton, attended by Phil Costa, Minister for Regional Development in the federal state of New South Wales. As Joe Di Leo, Managing Director of Allied Mills, highlighted in his opening speech, the new mill in Picton enables Allied Mills “to realize significant improvements in the efficiency of its production and – thanks to the connection to the railroad and its links to interstate – supply our customers in the Greater Sydney area.”
What’s more, he is proud of having set new standards for the milling industry in New South Wales and across the whole of Australia, not only by choosing the slip-form construction method, but also by using state-of-the-art milling technology.