BC Works mountains

Air & Waste

Whatever our activity – mining, processing, hydroelectric power generation, or moving our supplies and products around the globe – we consider the potential to harm the environment through pollution. 

Our environmental technical experts work with our process safety and operational engineers to ensure our operating systems and processes are managed to prevent harmful discharges or releases to the environment. 

At a minimum, we comply with national and local environmental regulations related to waste management, water discharge and air emissions. We also apply our own standards, which set the minimum requirements to define, monitor and manage emissions at all our managed operations to prevent harm to people and the environment. These standards also require us to set performance requirements for resource efficiency, particularly relating to mineral and non-mineral waste management.

We contribute to sustainability initiatives across the value chain through our work with peers, industry associations, and customers. And we continually improve our due diligence mechanisms and assess the environmental performance of new suppliers and customers.


Wastes and residues from our operational activities are a key area of environmental risk management for us. We try to minimise our impact through careful waste management, including mineral waste such as waste rock, slag and tailings, and non-mineral waste such as used oil, office and processing waste. We do this across our operations in many ways.

From waste to soap

For example, at our Oyu Tolgoi operations in Mongolia, 40-50% of waste materials are diverted from the waste management centre through re-use and recycling programmes. Not only is this reducing the volume of materials going to the landfill (prolonging the operational life of the waste management centre landfill cells) but it is also supporting Mongolian communities and industries. Waste oil is treated for reuse as lubricants, waste plastic is recycled into plastic pellets for reuse in the manufacturing of other products, and plastic pellets are converted into packaging and medical sharps containers. Used cooking oil from our kitchens is purified by a local company and used to make soap. 

Making batteries from rock

For the past 90 years, we have been mining borates at our mine in the Mojave Desert in California, US. Borates are important minerals for fibreglass, fertiliser and the glass of your smartphone screens. The waste rock from borates mining is stockpiled on site. After investigating the stockpiled waste rock from borates mining material to understand its potential value, our team at Boron found high grades of lithium. Plans are now underway to build a demonstration plant that will extract the lithium from waste rock – helping reduce waste while also creating another product stream.

Using waste from aluminium processing to grow blueberries

For more than a decade, we have had a dedicated team – including scientists, and marketing logistics experts – whose job has been to find value from the 350,000 tonnes of non-bauxite residue by-products we produced every year from our aluminium operations in Quebec, Canada. Currently, 85% of this is used to make new products. For example, we have turned anhydrite, a by-product from our Vaudreuil alumina refinery in Canada, into a safe and effective fertiliser for local blueberry growers.

A new way to make cement

We are working with Geocycle Canada and leading construction materials company Lafarge Canada to reuse waste from the aluminium smelting process to make cement. This new product – called Alextra – is made from used potlining, as part of the aluminium electrolysis process that would otherwise go to landfill. Alextra is the result of years of research and development, aimed at finding new ways to deliver sustainable outcomes and value from used potlining. Lafarge Canada will produce on average one million tonnes of cement a year at its facilities in Bath, Ontario, using Alextra as an alternative to raw materials such as alumina and silica, which are commonly refined or mined for use in the manufacturing of cement.

"As a global leader in building materials, we are committed to living up to the responsibility of helping to create a zero-waste future. In order to achieve this goal, we need progressive partners such as Rio Tinto.”

- Travis Smith, Geocycle Canada

It is not always possible to reuse or recycle waste, so we continually develop technology and build facilities to manage it in ways that minimise adverse environmental and community impact, disposal costs and future liabilities.

2016: At our Vaudreuil alumina refinery in the Saguenay, Canada, we implemented a two-phased project to overcome technical, environmental and social challenges and ensure the refinery could continue to operate in the future. Following public consultation, we built a new facility to filter and reduce the volume of bauxite residue waste at the existing storage site.

2017: Our development of a drilling waste removal system was awarded a certificate of merit in Western Australia’s 2017 Golden Gecko Awards for Environmental Excellence. This award recognises leading practice and innovation in environmental management and provides an opportunity to share experiences between government, industry and the community.

2018: Our Iron Ore Mineral Waste Management team won an International Network for Acid Prevention (INAP) Best Practice award: “Pilbara operations exemplify global best practice and deserve international recognition”.

2021 performance - waste

  • Year in review
  • Year in numbers
  • 1,005 million tonnes mineral waste disposed or stored
  • 0.65 million tonnes non-mineral waste disposed or stored

In 2021, we renewed our focus on managing potential contamination from these sources. We conducted a detailed analysis of hazardous materials and non-mineral waste to assess and prioritise our contamination risks. To reduce further contamination risks, we are banning the use of PFAS (perfluoroalkyl and polyfluoroalkyl substances) in fire suppression systems at our sites by the end of 2022.

At some of our long-life assets, waste management practices of the past have led to a need for remediation in the present. For example, at New Zealand’s Aluminium Smelter (NZAS), which has operated for more than 50 years, a detailed site investigation was completed in 2021 to guide remediation work. The study identified localised areas of contamination confined to the smelter footprint, informing a targeted rehabilitation strategy for the site. NZAS has committed to removing all spent cell lining waste generated in the process of relining reduction cells with refractory materials, managing waste and remediating the site.

Air quality control, Cape Lambert, the Pilbara

Emissions and air quality

Clean air is critical for the health of our host communities and of the surrounding ecosystems. Our emphasis is on prevention, managing air quality through operational discipline and process improvement.

We comply with local and state regulations to protect air quality, and we also have our own air quality protection standard. This outlines requirements for how to monitor and manage air emissions at our managed operations. It also provides the framework to prevent, or otherwise mitigate effects that our activities could have on host communities and the environment. To do this, we work to understand our emissions and potential impacts, control emissions at their source, and implement strategies to deal with adverse conditions.

Mining processes, such as the use of fossil fuels, moving ores, waste streams, and smelting metals release gases and particulates into the atmosphere. The major air emissions from our operations are:

  • Greenhouse gases, predominantly from the generation of electricity, combustion of fuel, and the production of aluminium
  • Sulphur oxides (SOx), mainly at our aluminium and copper smelters and coal and fuel oil fired power stations
  • Nitrogen oxides (NOx) from burning fossil fuels
  • Gaseous fluoride emissions from aluminium smelters
  • Respirable particulate emissions – very fine particles from mining and processing operations and from burning fossil fuels

We monitor and control air emissions where we operate. Our site-based monitoring includes tracking and reporting air quality parameters at intervals related to the type of emission risk, and the requirements of stakeholders and regulators. We use this data on a continual basis to ensure mitigation and control systems are working as expected and to make adjustments where necessary.

Reducing greenhouse gas (GHG) emissions

In 2021 we announced new Scope 1 and 2 targets: We brought forward our 2030 target of reducing our scope 1 and 2 emissions by five years. We also tripled our 2030 target, increasing it to a 50% reduction in our scope 1 and 2 emissions.

2021 performance - air

  • Year in review
  • Year in numbers

Across the business, we continue to pursue improvements to air quality management, focusing on emissions of greenhouse gases and particulate matter and gases emitted by our operational activities including mining, materials handling, processing and transportation.

Many of our assets have multi-year air quality improvement projects in place. For example, at the Iron Ore Company of Canada (IOC), plans are under way to reduce emissions with additional dust collection and to reconfigure the stacks to improve dispersion in the atmosphere.

At our Atlantic aluminium smelting operations in Canada, enhanced monitoring for key air pollutants that links emissions and operational data has reduced response times for upset conditions. Phase 1 of this project has reduced, by 90%, the amount of time stack emissions exceed recommended particulate concentrations. 

In some instances, we did not comply with permissible emission limits. For example, our Kennecott smelter experienced temporary equipment failures that, for safety reasons, required us to vent gases containing sulphur oxides directly to the stack. This resulted in short-term non-compliance but we remained compliant with our daily and annual limits and our continuous monitoring system indicated there was no adverse impact on ambient air quality.



Improvement projects

Kitimat, British Columbia, Canada

Since 2013, we have monitored and evaluated the potential effects of sulphur dioxide (SO2) emissions from our modernised Kitimat smelter in Canada.

In 2020, a comprehensive review report was completed to assess the methods and results from the previous six years of this Sulphur Dioxide Environmental Effects Monitoring Programme.

The report – prepared by Qualified Professionals (QPs) and the British Columbia Ministry of Environment – evaluated concentrations of SO2 data gathered through the modelling and monitoring activities in the Kitimat Valley. The report found no evidence of harm from the smelter emissions to people, vegetation, soils and water ecosystems, and the QPs do not see signs of harm in the valley based on the six years of monitoring work.

Through all of the analyses, discussions and results of the comprehensive review, the QPs are confident in these conclusions and recommend going forward with a more consolidated, efficient environmental effects monitoring programme, including some adjustments to the KPIs for vegetation, soils and surface waters.

Gudai-Darri (Koodaideri), Western Australia

In an industry first, we are making dust suppression safer, more precise and sustainable at Gudai-Darri. In partnership with Caterpillar, we are developing autonomous water carts to manage potential dust emissions from our operational activities. This work began in 2020, with initial trials expected in July 2021 – we plan to have three fully commissioned autonomous water carts by the end of the year.

Water carts, currently manned, are used at major mines to suppress dust and assist with haul road integrity. They traverse the mine ensuring that haul roads are kept to a correct level of saturation – however, they are also a potential source of safety incidents.

By utilising autonomous vehicles, we are working to eliminate the risk of vehicle accidents on our sites. The autonomous cart will automatically drive around the mine, keeping track of where it has dispensed water, how quickly it evaporates and identifying when and how much water needs to be put down next. When water gets low, the cart will drive to the refill point and refill itself automatically. This will ensure that just the right amount of water is added to the road surface to reduce dust.

Additionally, this project will also help manage the mine’s water resources and minimise interruptions to the productivity of our autonomous truck fleet. 

Iron Ore operations, Pilbara, Western Australia

In 2020, we implemented a number of engineering controls across our Pilbara mines and ports to reduce dust exposure to our employees and contractors, as well as the risk of dust emissions from our operations.

At Nammuldi, we installed a dust collector to remove dust from within the iron ore screening facilities and reduce the risk of dust entering the atmosphere. We are also commissioning new dust collectors for the Yandicoogina, Paraburdoo and Tom Price sites in 2021.

In addition, other measures such as water cannons for spraying iron ore stockpiles and water carts for reducing dust from roads, open areas and enclosed facilities also help reduce dust emissions from our sites.

During the year, we also standardised our dust governance process across all our Pilbara sites. This work promoted ownership of dust management, making it easier for employees to understand its importance, raise concerns and implement improvements.

Our Iron Ore dust mitigation programme is part of a broader Health and Hygiene Management Plan (HHMP) that addresses dust, water and noise management in a targeted way. The HHMP supports compliance with our regulatory requirements and the management of potential impacts on host communities and the environment.

Queensland Alumina, Queensland, Australia

As part of a commitment to improving environmental performance and ensuring a 50-year old refinery continues to meet current standards, QAL announced a five-year Environment Strategy (5YES) in August 2018.

In September 2018, QAL experienced an alkali release that left the boundaries of the refinery. In December 2020, QAL was found guilty by Gladstone Magistrates Court of unlawfully causing serious environmental harm and contravening a condition of the Environmental Authority issued by the Queensland Government’s Department of Environment and Science.

Since this incident, the operation has made significant progress toward improving environmental performance – including by introducing a Process Safety Management system that puts controls in place to further mitigate the risk of process incidents occurring. The system has been operating effectively for two years.

With the design work now completed on the 5YES, QAL estimates the investment in projects and solutions will be A$400 million. It will improve performance in the areas of:

  • Air quality (dust, odour and caustic releases) – reduce emissions and improve controls
  • Water – reduce the level of impact to waterways
  • Land – prevent and remediate contamination to land
  • Noise – engineering solutions to reduce noise

Recognising that the culture of an organisation is a significant factor impacting its environmental performance, QAL is also redefining the way employees view environmental risk by:

  • Continuing to adopt a process safety management system to identify critical controls for major hazards, which are very closely associated with environmental issues
  • Instituting due and proper consideration of environmental obligations in their everyday tasks, as well as understanding of the upstream and downstream impacts of their tasks and materials – transitioning from a workforce to environmental stewards

The team at QAL has already completed 30 of the 60 projects and invested A$189.7 million to date, of which A$84.2 million has been spent with local suppliers and manufacturers within Gladstone.