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Reducing emissions, improving quarry sustainability


Sustainability improvement is no longer an option for any aggregates company – it is more a case of when, not ifthese initiatives are wholeheartedly embraced by the industry. Steve Franklin, principal of Cement & Aggregate Consulting, explains.

Sustainability is increasingly the focus of investors and the community alike. The increased cost of capital and public outrage expressed against companies with poor environmental, social and governance (ESG) records are becoming more and more common and there is an ever increasing demand for not only action to be taken but to ensure that companies have a clear plan. A recent article in the Australian Financial Review noted:

“ESG is likely to undergo a journey similar to workplace safety – change will only come from strong leadership, better processes and a fundamental shift in culture from the boardroom to the front line.” (AFR, 30 March, 2021)


Sustainability improvement is not an option for any company – it is more a case of when these initiatives are wholeheartedly embraced, not if.

“A coalition of the world’s biggest investors will push companies to align capital spending with emissions reduction pledges after determining that none of Australia’s biggest emitters have climate targets fully aligned with the goals of the 2015 Paris Agreement.” (AFR, 23 March, 2021)

And per the Macquarie Bank 2020 ESG Ratings Report:

“The basket of companies with the highest ESG scores has outperformed the bottom basket since the inception of our survey in 2011. There is a strong relationship between revisions to ESG scores as a signal for future performance. Companies with the largest positive revisions to their ESG scores have delivered better returns than those with negative revisions, by 5.1 per cent on an annualised basis.”

Decarbonisation of the quarry industry is being addressed by multinational and local industry players alike to improve their performance and meet ever more stringent sustainability criteria.


Our experience shows that significant carbon dioxide (CO2) emissions reduction is possible in most operations through the techniques identified in Figure 1.

Figure 1. Sustainability approach.

What can be done about it?

Emissions within quarrying can be broken down into three broad types:

  • Scope 1 (from diesel).
  • Scope 2 (from electricity generation).
  • Scope 3 (from supply chain and transport).


Multiple efforts are required to address the main sources of emissions, including better resource definition and extraction planning, operational efficiency improvement, new drivetrain technology and a switch to green electricity.

Improved resource definition and extraction planning

Probably one of the best ways to reduce Scope 1 emissions is simply not to dig up material that is not economic to extract. The use of resource optimisation and scheduling tools ensures that there is a viable extraction plan for the deposit that:

  • Clearly identifies what is economic to extract and the stages to extract it.
  • Reduces overburden movement (and double-handling).
  • Ensures that there is a clear picture of what areas need to have vegetation removed and which can be rehabilitated.
  • Budgets, not only operational and capital expenditure, but the estimated CO2 impact of the plan.

The combination of Seequent’s Leapfrog Geo software for resource modelling and Deswik.Suite software for resource optimisation, design and scheduling will have a profound impact on how we plan and extract deposits and maximise net present value (NPV).

You need to baseline your extraction operations, work out how improved resource definition and extraction scheduling/planning will improve sustainability and provide estimates on how CO2 kilograms per tonne will be reduced accordingly.

Improved operational efficiency

Significant improvement in operational efficiency can be achieved in a range of ways such as:

  • Providing a link between strategic resource planning and operational plans.
  • Ensuring that load and haul fleets are matched to production requirements.
  • Loading haul trucks to the correct payload.
  • Not double-handling material.
  • Eliminating unnecessary idling and unproductive use.
  • Upgrading equipment to more fuel-efficient models.

Central to all improvement actions are the need for robust data collection and analysis using agnostic quarry information systems [] that can pull data from a wide range of sources.

Being able to bring together the relevant data from the different data silos that most companies have, can provide profound insight into operations and when combined with artificial intelligence (AI) and machine learning, will revolutionise how we view our businesses.

These systems also ensure that we can monitor emissions versus plan and provide robust, auditable data.

Drivetrain advances

To become fully carbon neutral, a change in drivetrain technology is required. We believe that there is significant opportunity for the use of electric trucks – particularly electric autonomous haul trucks – in quarries.

By way of example:

The Volvo CE Electric Site pilot conducted during a ten-week period at a quarry in Gothenburg, Sweden as a partnership with construction company Skanska. The pilot included electric and hybrid autonomous vehicles and resulted in up to 98 per cent less emissions of CO2

More recently we have seen trials at Holcim’s Gabenchopf quarry in Siggenthal, Switzerland which we believe will lead to a significantly greater understanding of the value of this technology and how best to apply it.

We are actively involved in research and collaboration in this field with leading players in this field.

It is worth noting that work done to improve resource optimisation, extraction scheduling and detailed planning is a vital part of this evolution and one that we have now been working on for some years.

Sustainable fuels

Options exist for mobile equipment to switch to liquid sustainable fuels (biofuels or synfuels) with the potential to decrease carbon emissions by 70 per cent, while using existing equipment and infrastructure.

Further opportunities exist to power equipment by hydrogen, with the first hydrogen-powered road trucks arriving in Australia this year and a hydrogen-powered drill rig and large haul truck already in testing with Fortescue Metals Group.


The processing of material requires a significant amount of energy. While this can be offset with “green electricity”, true reduction will require a difference approach.

Better identification of material that should be processed

A good understanding of site geology can have a big impact on Scope 2 emissions – in short, material that is marginal is identified before processing and not put through the plant – this can have a significant impact, particularly for sand operations.

A reassessment of the cost of roadbase

Many sites produce roadbase at near cost, often using high quality rock in the process. If a carbon tax is put in place, this practice will need to change as companies will be forced to either increase prices or not produce these materials. This is likely to drive changes in pavement design as sites only produce roadbase from materials that are not suitable for high quality aggregates or as needed to maintain site development.

Reduction in the use of mobile crushing plants

Mobile crushing plants, particularly diesel-powered ones are likely to fall from use as the cost of CO2 emissions preclude their use, resulting in changes to how low value products are produced and how these plants are used to supplement regular production.


Once baseline CO2 emissions are determined, actionable plans to predict and reduce emissions are required. Digitalisation of operations is a critical part of how we see the industry changing, namely:

  1. A digital twin of the extraction operation that provides accurate survey, geological, geotechnical and quarry design information.
  2. An optimised resource based on geological and market data to maximise NPV and guide extraction.
  3. A robust quarry operating plan to ensure planning results in front-line outcomes. This needs to be appropriately resourced with the technical team to manage it, the needed software and the geospatial tools such as Trimble Stratus, drill rig hole navigation systems, machine guidance and GPS survey equipment.
  4. Operational performance management systems to provide stakeholders with actionable insights to control and correct operational performance. Having accurate, validated, and timely data opens the door to machine learning, artificial intelligence and better decision making.
  5. Autonomous and electric machines to significantly reduce emissions, increase efficiency and improve safety. It will be difficult (some would say impossible) to reap the benefits of this technology without first having first implemented the preceding four steps.

There are solutions to help move quarries to net zero. These initiatives will not only improve sustainability, they will reduce operating costs as well, making them self-sustaining.

Steve Franklin is the Principal Consultant for Cement & Aggregate Consulting (aka Cemagg), based in Brisbane. For more information, tel +61 474 183 939, email or visit

This article is reproduced with kind permission from the Cemagg website.

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