In 2019, Alex Fraser Group, one of Australia’s largest recycled aggregates producers, officially flicked the switch on two glass recycling and sustainable asphalt plants at its Laverton site. Damian Christie spoke to Peter Murphy about the site’s recycled aggregate operations on the first anniversary of the opening.
On 31 May, 2019, Alex Fraser Group formally opened a high recycled technology asphalt plant and an innovative glass recycling plant, originally estimated at $20 million. The glass recycling plant was- believed to be the first of its kind in the world to separate contaminants from glass waste during processing.
A year on, the fully operational plants are supplying recycled road base, aggregates, sand and asphalt to Victorian road and rail projects. The plants have complemented a decade-old construction and demolition (C&D) recycling facility in the heart of the 34ha Laverton North site that processes up to one million tonnes per annum (tpa) of recycled concrete, asphalt and glass for use in major road projects, suburban road upgrades, level crossing removals and civil construction applications throughout Melbourne.
Use of these materials is contributing to significant commercial and environmental savings across the Victorian construction materials industry – including reductions in landfill, heavy vehicle movements, and the carbon footprint of new infrastructure projects. It is estimated that about 50 per cent of Victoria’s recycled C&D materials originate from Alex Fraser Group’s three Victorian sites in Laverton, Clarinda and Epping.
GLASS SAND RECYCLING
The bespoke 875m2 glass recycling plant was the culmination of more than a decade’s work. It was designed to produce up to 800 tonnes of high specification sand per day by “dry screening” the problematic glass waste streams – up to a billion glass bottles per year – that are frequently co-mingled with other materials, such as paper, plastics, metals and organics.
The glass recycling plant consists of crushers, two feed bins, 16 conveyors, two large screens, magnetic separators, air knives and other sorting technology. The magnets and knives remove kerbside contaminants from the glass such as metals and plastics. The waste glass, depending on how contaminated the raw material is, goes through between six and eight passes of cleaning and sorting before crushing.
Peter Murphy, the managing director of Alex Fraser, told Quarry that while the plant has performed well in the past year, it is not without its challenges.
“This is a really challenging stream of material to process,” he said. “If anything, over the past 12 months the material has become more difficult to sort. The people working on the plant have done a great job of learning how to operate and maintain it efficiently. They’ve also been persistent at implementing incremental improvements to improve productivity. This will continue over the next 12 months.
“We set a target of 100 tonnes per hour, and the material type makes this very challenging,” Murphy added. “We aren’t consistently there yet but it is improving and will continue to improve as we make refinements.”
The end product of the recycling plant is Alex Fraser’s “Green Roads” recycled sand, which is designed to directly replace quarried sand and reduce the need for trucking virgin sand long distances into Melbourne, substantially reducing heavy vehicle movements on congested roads.
The glass sand is used in road base and pipe bedding in metropolitan civil construction applications, and for the manufacture of energy-efficient, warm mix asphalt – notably the VicRoads-certified Glassphalt and PolyPave, generated by Alex Fraser’s recycled asphalt plant.
ASPHALT, C&D PLANTS
Like its glass recycling counterpart, the 40-metre high sustainable asphalt plant, designed and installed in conjunction with global asphalt equipment manufacturer Ammann Group, was the result of an intensive global assessment of asphalt production technology. The plant produces high quality materials using recycled content as its main input and only supplements virgin materials where necessary. Instead of raw materials being trucked in from up to 100 kilometres away, Alex Fraser Group’s raw materials come from a mere 100 metres away.
Unlike the bespoke glass and sustainable asphalt recycling plants, Laverton North’s C&D recycling facility has been relatively conventional, operating much like any other plant set-up that would be found in a regular quarry – but it is nonetheless still an important contributor to the Laverton site’s output. Indeed, the C&D plant has in recent years set records – in May 2019, it despatched more recycled products than in any other single month in its first decade of operation.
The C&D recycling plant has employed an Astec Industries/Johnson Crushers International (JCI) Kodiak K400+ cone crusher for secondary concrete, brick and rock crushing. Earlier this year, Alex Fraser purchased a JCI Kodiak K500+ to take over the duties of its predecessor; the K500+ now acts as a secondary crusher in the processing circuit when being employed for concrete and brick crushing, and can also process rock when the plant is in that configuration. The K400+ is still active and is now positioned as a secondary unit behind the jaw crusher.
Combined, the C&D and glass recycling plants give the Laverton North site, according to Murphy, “a capacity of well over a million tonnes a year”. This, he says, is “in addition to the high recycled technology asphalt plant”, which has a potential output of 500,000 tonnes of recycled asphalt products per annum (tpa). Upon coming online in May 2019, it was thought the glass recycling plant had the potential to produce up to 200,000 tpa of recycled glass sand.
This capacity in excess of one million tonnes of recycled raw materials per annum is potentially good news for the quarrying industry and the environment alike.
It means there is enormous potential for virgin materials to be conserved for other infrastructure purposes, there are less demand and supply pressures on quarry producers – particularly as a new wave of construction projects are expected to ramp up post-COVID-19 – and up to half a million tonnes of raw waste materials every year (glass, brick, concrete, asphalt, stone) is diverted from landfill and reused in infrastructure.
“Each tonne of recycled material replaces at least one tonne of virgin material,” Murphy said. “In fact, the density advantage means that to replace a tonne of recycled material, you often use a bit more than a tonne of virgin material.”
As demand continues for government-sponsored infrastructure projects around Australia to comprise a specified proportion of recycled aggregates, and with Victoria particularly focused on its Recycling First program, Alex Fraser Group’s contributions to civil construction projectswill very likely increase. That will mean upgrades to plant and equipment as needed across all of its sites, including at Laverton.
“We have consistently invested in all our sites and there’s always improvements to be made to safety, productivity, and housekeeping,” Murphy said. “Our immediate focus on the [Laverton] site is further improvements to traffic management, equipment storage, working at heights and some simple productivity improvements.”