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Recycling, Plant & Equipment

Articles from RECYCLING (251 Articles), SAND PROCESSING EQUIPMENT (166 Articles)











A “glass mountain” at Alex Fraser Group’s Laverton North processing plant.
A “glass mountain” at Alex Fraser Group’s Laverton North processing plant.

From sand to glass – and back to sand

Recycled aggregates - once thought secondary to virgin quarry products - are now being used more frequently in construction applications. Damian Christie spoke to Alex Fraser managing director Peter Murphy about how the company’s products can benefit the extractive industry.

It is little known amongst most environmentally conscious residents that not everything in their recycle bins every fortnight – eg glass, plastics, paper – necessarily makes it back into the public sphere as part of a reusable resource.

In particular, of the 250,000 tonnes of glass collected from Melbourne’s kerbsides, about 40 per cent (or 100,000 tonnes) still goes to landfill or is stockpiled in “glass mountains” because it cannot be recycled using customary methods.

Indeed, in some jurisdictions, particularly the US, local councils have abandoned the kerbside collection of glass for recycling. This is because it is simply not cost-effective to collect and recycle glass or the municipalities lack viable markets for glass residuals.

Not only does glass waste threaten the viability of kerbside collection, thereby driving up collection costs for councils and ratepayers, but those parties also face the prospect of rising construction costs. Virgin aggregates resources around Australia are not finite and in time will disappear from metropolitan areas.

Indeed, New South Wales is already experiencing rising construction expenses as aggregate products have to be transported from the regions to meet the demands of a massive infrastructure boom in and around Sydney. Population growth in south-east Queensland and a booming economy in Victoria will, over time, also contribute to a depletion in raw construction materials in Brisbane, the Gold Coast and Melbourne, and the need to transport more aggregate products from regional Queensland and country Victoria.

The Victorian Government last year released a report that attempted to “crystal ball” Victoria’s projected population growth and urban development to 2050. The Extractive Resources in Victoria: Demand and Supply Study 2015-2050 estimated that nearly 90 million tonnes of stone, sand, clay and other materials would be needed annually by 2050. Of 11 billion tonnes of resources available within current and future planned authorised areas, 34 per cent of the supply would need to be sourced from different quarries to those currently in use or indicated for use (due to resource exhaustion). The report also highlighted the importance of sourcing raw materials as close as possible to construction sites to cut transportation costs and better manage transport infrastructure.

To reduce the anticipated costs of the kerbside collection of glass and construction materials, recycled aggregates – which were once only thought complementary to virgin quarry materials – are becoming a vital cog in the booming infrastructure machine.

The Alex Fraser Group is amongst the recycled aggregates producers around Australia diligently working to provide viable, reliable and cost-effective alternatives to virgin quarry materials.

Even after being screened through resource recovery and glass facilities, it is not unusual for foreign materials (eg bottle tops) to be mixed in with raw glass fines.
Even after being screened through resource recovery and glass facilities, it is not unusual for foreign materials (eg bottle tops) to be mixed in with raw glass fines.

From residues to recycling

Alex Fraser Group was established in 1879 and is one of Melbourne’s oldest companies. Founder and principal Alex Fraser started the group as a metals trading business before retiring in 1920, when employee Archie McKellar acquired an interest in the company.

In the 1950s McKellar identified the dross and residues business as a lucrative enterprise, and he established a flourishing army surplus materials and equipment recovery business that encouraged Alex Fraser Group to recycle scrap and demolition metals. By the 1970s McKellar’s son and successor Jamie McKellar OAM recognised that large quantities of concrete rubble could be salvaged from landfill and – consisting as it did of aggregates, sand and cement – returned to its natural state with the right processing for reuse in construction applications. Alex Fraser subsequently expanded into construction and demolition (C&D) recycling in the 1980s.

In the 1990s Alex Fraser formally received VicRoads accreditation for its products and worked on the initial stage of Melbourne’s Western Ring Road Project, for which it supplied 175,000 tonnes of Class 2 cement stabilised roadbase. Further contracts followed, including the supply of construction materials for Melbourne’s Albert Park Formula 1 grand prix circuit. In subsequent years, the company has collected numerous awards, including the Gold Banksia Environmental Award (Australia’s highest honour for recycling initiatives), and the Prime Minister’s Australian Business Award for Environmental Leadership.

Alex Fraser Group has evolved into one of Australia’s leading C&D recycling contractors, with bases in Victoria and Queensland. At present, its range of recycled aggregates includes C&D materials, roadbases, drainage aggregates, recycled sand and hot mix asphalt, which are used in building construction, commercial construction, freeway construction, pipelines and subdivisions.

According to Alex Fraser Group’s managing director Peter Murphy, production across all the company’s sites averages more than three million tonnes per annum. In 2016 Alex Fraser achieved a “major milestone” of recycling 40 million tonnes of C&D material. The company employs a range of quarry-spec crushing and screening plant within its Melbourne and Brisbane operations.

“We are proud to employ more than 300 highly skilled people, who are dedicated to safely and efficiently operating and maintaining our plant and equipment to meet our industry leading targets in productivity, safety and customer service,” Murphy said.

Small pieces of broken glass or colour sorted glass are screened as raw glass fines and shipped to Alex Fraser Group for recycling into sand.
Small pieces of broken glass or colour sorted glass are screened as raw glass fines and shipped to Alex Fraser Group for recycling into sand.

Glass recycling

Alex Fraser Group estimates there to be about 500,000 tonnes of waste glass stockpiled in “glass mountains” across Melbourne. Rather than sending the contents to landfill, the company has spent the best part of 14 years collaborating on research and testing with a range of parties to develop products from stockpiled glass fines that could be incorporated into high specification construction materials for road and infrastructure building. These parties included government agencies, VicRoads, universities, and partners such as Visy Recycling, and Alex Fraser Group’s own customers.

Alex Fraser Group’s product range has now extended to glass sands – sold under the banner of Alex Fraser Recycled Sand and Glassphalt. By the end of 2016 the company had sold more than 300,000 tonnes of recycled glass sand and incorporated 11,000 tonnes of recycled glass into its asphalt products.

The high quality Alex Fraser Recycled Sand is suitable for numerous applications including asphalt (to Section 407 of VicRoads specifications), roadbase, pipe bedding and granular A2 filter material applications. This makes up 90 per cent of Alex Fraser Group’s recycled glass sand products.

Glassphalt – a VicRoads-registered pavement material that utilises glass as a component in the manufacture of hot mix asphalt – accounts for the other 10 per cent.

VicRoads, water authorities and local government have used more than 300,000 tonnes of the recycled glass sand in ongoing asset maintenance and large-scale infrastructure projects. Alex Fraser Group has also contributed to the following developments:

  • More than 8300 tonnes of Alex Fraser Recycled Sand was supplied to the 185,000m2 Webb Dock West automotive terminal. Alex Fraser Asphalt also provided nearly 30,000 tonnes of deep and thin lift asphalt, which comprised a high percentage of recycled content.
  • Recycled Sand supplemented almost 270,000 tonnes of crushed concrete on the 6.4km Dingley By-Pass, which links Warrigal Road in Moorabbin and Westall Road in Dingley Village in Melbourne’s south-east. A 5mm spec Recycled Sand was also supplied to the 19km Dingley Arterial road between Moorabbin and Dandenong South (on top of 110,000 tonnes of crushed concrete).
  • The company contributed Recycled Sand as drainage filter material on the M80 upgrade from Calder Freeway via Sydney Road to Sunshine Road (on top of 143,000 tonnes of recycled concrete) and as part of 60,000 tonnes of recycled capping on the CityLink Tulla widening project (on top of 90,000 tonnes of dry and cement-treated crushed concrete).
  • Asphalt including recycled glass sand (Glassphalt) has been laid down on Fitzroy’s iconic Brunswick Street. A percentage of recycled glass was used in a warm mix asphalt incorporating reclaimed asphalt pavement.
  • Melbourne Water’s 10,500ha Western Treatment Plant in Werribee has used more than 15,000 tonnes of 5mm spec Recycled Sand as pipe bedding.
Volumes at Alex Fraser’s Laverton North premises are managed “very similarly” to a quarry operation, courtesy of a high capacity, purpose-designed, fixed plant.
Volumes at Alex Fraser’s Laverton North premises are managed “very similarly” to a quarry operation, courtesy of a high capacity, purpose-designed, fixed plant.

Glass to sand processing

Peter Murphy explained that glass goes through several stages before delivery to Alex Fraser Group. Glass is transported to a materials recovery centre, where it is mechanically separated from other recyclable materials such as paper, cardboard and metals. It is then diverted to the Visy Glass plant in Laverton North, where it is sorted by colour for potential use in the production of new glass containers. The glass that is broken into small pieces or is too small to be colour sorted is screened out as raw glass fines and shipped to Alex Fraser Group for recycling into sand.

“These screenings successfully separate most of the different recyclable materials,” Murphy said. “However we still work closely with our customers who bring us the materials. Our people monitor the material quality closely at each step with the use of specialised equipment.”

From there, Murphy said, the conversion of glass fines into sand is a complex process. It involves “multiple stages of crushing, screening, and sorting via air and magnetic separation”. Murphy has previously said in other interviews that the company manages its volumes “very similarly” to a quarry operation and its preference is for high capacity, purpose-designed, quarry-spec fixed plant that is efficient, safe to use and has environmental benefits.

The challenge Alex Fraser faced in commercialising the recycled glass waste stockpiles was bedding down a process that could handle high volumes and achieve economies of scale. “Our glass to recycled sand production figures vary year on year in correlation with industry demand”, Murphy added. “On average, Alex Fraser produces around 100,000 tonnes of recycled glass products each year. Our record to date was achieved in 2015, with more than 140,000 tonnes of recycled glass sand produced. We have invested a lot into research and development to establish the most efficient process to recycle waste glass into a high quality sand that is a valuable resource for the construction industry.”

Environmental benefits

The most obvious environmental benefit of producing recycled aggregates from glass and other C&D materials is the preservation of virgin aggregate materials – and especially declining sand deposits – for the future. As Murphy contends, recycled aggregates assume greater importance in that context.

“We know that good quality virgin sand and rock is increasingly difficult to source close to major cities, and the Victorian Government has quantified the cost of this increased trucking task in a very detailed study,” he said, referring to the Demand and Supply Study 2015-2050. “Recycled construction materials are essential to service the demands of growing cities.

“Recycled sand has been proven to be an effective substitute for virgin sand in concrete applications. As sand supplies close to the city are exhausted, we expect more recycled sand to be used in concrete.”

Alex Fraser Group has paid close attention to transport as part of its service, matching the volume of its tippers to the density of its recycling material.
Alex Fraser Group has paid close attention to transport as part of its service, matching the volume of its tippers to the density of its recycling material.

What is perhaps lesser known in the extractive industry is the potential impact of density savings from recycled aggregates on broader transport costs and carbon emissions. Alex Fraser Group has paid close attention to transport as part of its service, matching the volume of its tippers to the density of its recycling material, as well as optimising wheel loader bucket sizes to the material density for fewer loading passes. As a result of this finetuning, the company has cited many positive statistics from the density savings of its products:

  • At Webb Dock West, the utilisation of recycled materials meant there were 520 fewer truckloads and a carbon saving of 1567 tonnes.
  • On the M80 upgrade, there was a saving of 12,000 tonnes of quarried material; there were 297 fewer truckloads and a carbon saving of 921 tonnes.
  • On the Dingley Arterial, 10,000 tonnes of quarried material was conserved, equating to 340 fewer truckloads and a reduction of 710 tonnes in carbon emissions. Similarly, on the related Dingley By-pass, 23,000 tonnes of virgin quarry materials were saved due to the density savings of Alex Fraser Group’s recycled aggregates; there were 770 fewer truck movements and a cut of 1695 tonnes in carbon.
  • The warm mix asphalt used on Brunswick Street reduced carbon emissions by more than 30 per cent.
  • Murphy said the average density saving on projects normally equates to 10 per cent. “This means a 10 per cent saving on all associated costs,” he said. “This has a significant knock-on effect, decreasing the number of truck movements, decreasing cartage costs, decreasing traffic and congestion.”

Most importantly, the company’s customers have been pleased with the quality of the material.

“Alex Fraser recycled products have been well and truly proven over several decades, so they are well supported by anyone experienced in the construction industry,” Murphy said. “Indeed, given the density  and environmental benefits, many constructors prefer our products over virgin quarried materials.”

Continuous improvement

Alex Fraser Group, however, won’t rest on its laurels. It engages in continuous improvement of its products, having worked closely over many years with regulators and academic institutions to perfect its materials and processes.

The company has also obtained ISO certification for its quality management, occupational health and safety and environment systems.

Murphy says while continuous improvement is important – it “goes beyond Alex Fraser, impacting not only our customers, but the entire community” – and the company’s ISO processes are beneficial, “we find that engineers are less interested in whether it is recycled material and more interested in whether the supplier can demonstrate reliability. Our customers’ main interest is whether we stock and deliver enough product to keep their job flowing seamlessly – and we pride ourselves on ensuring that we can”.

A close-up of the end product – Alex Fraser Recycled Sand.
A close-up of the end product – Alex Fraser Recycled Sand.

To that end, Alex Fraser Group will continue to innovate on products and to finetune its processes to provide a service that is as comparable and competitive as the next quarrying operation. “We have some very persistent people and we continue to invest in improved technology so we are able to make a very consistent, high quality end product,” Murphy said.

In a maturing national market, it is likely Alex Fraser and other recycled aggregates producers will become even more valued as the hunger for more infrastructure places additional pressure on existing and future quarry reserves.

In turn, these producers will also continue to build their environmental credentials. The fickleness of growing populations will lead to more disposable C&D materials such as glass being diverted towards the development of glass sands and other alternative materials – and ironically the conservation of extractive resources in strategic areas.











ABOUT THE AUTHOR
Damian Christie
Editor • Quarry Magazine

Damian Christie is the editor and a chief writer of Quarry magazine. To contact Damian, please click here.
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Sunday, 16 June, 2019 4:56pm
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