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Opportunities for C&D materials to support growth of global cities


Resource recovery and utilising alternative construction materials to support urban growth came under the spotlight as part of a recent Engineering Insights virtual event hosted by wet processing industry experts CDE.

The second edition of the event, held across three days from 18 to 20 May, followed a successful 2020 inaugural conference which was developed in response to a desire for industry professionals to engage in global learning and networking in the absence of international tradeshows and in-person conventions.

To support the continued sharing of insights and facilitate pertinent discussions about the global market, CDE convened industry leaders from across Australia and programmed a series of dynamic presentations discussing the supply and demand of geological construction materials and landfill diversion in the demolition industry.


A regional plan published by the Greater Sydney Commission revealed Greater Sydney’s population grew at an annual rate of 2.5 per cent for most of the 20th century. Today, that makes Greater Sydney one of the top 10 fastest-growing regions in the Western world. [1]

That rapid population growth and significant demographic shift is set to continue.

The plan also projects that an additional 3.2 million people will call Greater Sydney home by 2056.

Dugald Gray, the principal at Ecoroc, said that of the 40 million tonnes of construction material required to meet demand in the region, 42 per cent came from alternative materials including virgin excavated natural material (VENM) and sandstone.

“They’re used in large quantities, they’re low value, they’re generated within the city, and from a sustainability perspective they’re fantastic,” Gray said during a panel discussion assessing the supply and demand for geological construction materials in global cities.

He was joined by Daniel Webber, CDE’s regional manager for Australasia, Mitchell Bland, managing director at RW Corkey & Co, and Quarry editor Damian Christie.

Gray said that such materials can be used as a substitute for road base, hard sand and other materials used for filling voids. He added it also reduces the burden on finite virgin sand and aggregates by ensuring quarry operators can earmark freshly quarried materials for higher strength and higher value applications.

“As a consequence, what that allows for is hard rock quarries to maximise the yield of aggregates they produce for concrete or asphalt,” Gray said.


Mike Ritchie, managing director at MRA Consulting Group, one of Australia’s leading environmental consultancy firms, remarked that New South Wales has in place an 80 per cent landfill diversion target for construction and demolition (C&D) waste by 2030, adding that more work needs to be done to meet it.

“We are not there yet but it is positive,” Ritchie said. “C&D recycling rates sit at 74 per cent. C&D is highly recyclable due to its consistent strains of materials and therefore lends itself to higher recovery rates. Government is using landfill levies to move the industry towards hitting the 80 per cent target.”

He was speaking during the session about resource recovery and diversion from landfill for the demolition industry.  At this session he was joined by Mark Smith, CEO of the Waste Recycling Industry Association Queensland (WRIQ), Mike Wheeler, editor of Inside Waste, and Marcus Barber, representing the City of Greater Dandenong.

“We haven’t reduced the amount of tonnes landfilled in the past 20 years,” Ritchie explained.

“To hit the 80 per cent target, we are going to have to do a lot more work. To reach this national target by 2030, we need to double our historic recycling rate. This is only possible with the right market and pricing signals.”

He said government levies have done the “heavy lifting” in terms of recycling growth over the past two decades. Analysis by his consultancy shows the relationship between recycling rates and levies confirms the higher the levy the greater the recycling rate.

“We need to continue to advocate to the government to ensure everyone understands the benefits of levy and price signals in terms of making C&D recycling profitable and worth investing in.”

Ritchie added the recycling industry is worth investing in. “We have major investors coming into the waste market now to invest in C&D companies,” he said.

While Ritchie focused on landfill diversion, Smith highlighted the importance of how products and buildings are designed to begin with and the need for an end of life solution for products used.

Advocating for the use of recycled products in the construction sector, Barber suggested concrete produced from C&D waste materials has its applications.

Referencing a UK-based customer, he said, “They have been bold, and they guarantee their products. They say this concrete is good enough for a car park. They’re maybe not going to build an airport runway with it but leave virgin extracted material for the right places.”


The three-day program featured 16 sessions involving almost 50 speakers.

CDE Group’s CEO Marc Jennings said that company was proud in 2021 to build upon its objective in 2020 “to bring together industry leaders and professionals virtually to discuss the prevalent issues of the day” through hosting its second Engineering Insights virtual symposium.

“We have continued to facilitate global learning and our conference was once again a huge success, as 600 industry professionals registered, engaging with our event from around the world,” Jenning said.

The full Engineering Insights program is available to view on demand for registered attendees. Visit

The session on the material needs of the Greater Sydney Region can also be viewed at or

[1] Greater Sydney Commission. Greater Sydney Region Plan, A Metropolis of Three Cities.

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