Think big IROC

How strategic dust management is improving our air emissions

The health and safety of our people and the communities we are a part of will always be our number one priority. That’s why we have a focus on the management and control of dust that mining operations can generate, to prevent potential impacts on air quality, health and the environment.

We have been implementing controls to minimise dust emissions for a number of years across our operations and continue to invest to improve our performance. We are increasingly taking a more strategic approach and by leveraging technology and engaging our people and communities on innovative approaches, we are finding new ways to both reduce dust generation and improve community amenity and productivity.

Taking a ‘pit to port’ approach to dust management at Western Australian Iron Ore (WAIO)

Managing the potential for dust emissions across mine, rail and port operations is not new for WAIO; it is something we’ve been doing for a long time. We are one of several iron ore producers shipping product out of Port Hedland: in 2019, BHP exported 270 million tonnes of the average 500 million tonnes of ore that goes through the port each year. Due to actions we and others have taken over the last eight years, we have seen a significant reduction in events creating elevated levels of dust emissions, despite increasing port throughput.

In the past decade, BHP has invested over A$400 million in projects to minimise dust emissions across our supply chain, with the objective of improving air quality and amenity both inside and outside the boundaries of our operational activities. This has included:

We have plans to continue to improve. In April 2020, we announced plans to invest up to an additional A$300 million over the next five years to further reduce dust emissions, including implementation of operational dust control projects across our entire Pilbara supply chain from pit to port, such as moisture management systems, ore conditioning and monitoring infrastructure, and improvements across our existing controls at our mines and port (more information here). This announcement reinforces BHP’s commitment to the long-term, sustainable future of the Pilbara region as an economic powerhouse.

As well as continuing to evolve our approach to managing dust to reduce workforce exposure, we will also continue to work closely with government and industry to deliver further dust management controls and support strategic land-use planning to reduce potential community exposure.

Engaging innovation and technology to drive our zero-dust ambition at Spence in Chile

At Spence copper mine in northern Chile, we have implemented an integrated air quality strategy designed to standardise our approach to dust management in light of changing expectations by regulators and communities. The four areas of focus for the dust strategy are: air quality performance, improving dust management controls, protecting our workforce and engaging stakeholders.

Chilean air quality regulatory standards are expected to tighten over the next 10 years as the country moves towards the World Health Organization (WHO) guidelines, which are three times more stringent than current PM10 limits (particulate matter smaller than 10 micrometers in diameter). The integrated air quality strategy is designed to further protect our workforce and communities by adhering to WHO guidelines and interim targets set by BHP as Chile reviews its regulatory regime.

We have set ourselves a ‘zero-dust’ ambition and engaged with local start-up companies to assist us by developing innovative solutions to monitor and eliminate dust, with an initial target to reduce 2019 PM10 dust emission levels by 60 per cent by 2025. The dust mitigation measures aim to reduce emissions from all sources, including roadways, drilling and blasting, stockpiles, crushing plant and concentrator operations, material transfers, the tailings dam, wind erosion and construction and project activities. Comprehensive monitoring and modelling will inform and help us target our improvement efforts.

For instance, although dust emissions from drill and blast activities are currently low (1 per cent) compared to emissions from hauling (48 per cent) and from open, unsealed areas of the mine and the crushing and screening plants (33 per cent), they are a potentially significant source of workforce exposure. We introduced large scale blasting pilot at Spence last year to reduce that exposure, as monitoring indicated that large scale blasts have an overall positive impact on potential workforce exposure to PM10 dust emissions compared to conventional blasts, as fewer blasts are required.

Other technology-based initiatives include a regional PM10 dust emissions model that predicts conditions which could result in potentially harmful levels of dust to people at the Spence mine and the nearby Sierra Gorda community. This model predicts PM10 dust emissions variations up to 9 days in advance, anticipating instances of potential workforce and community exposure and allowing proactive management of mining activities to reduce emissions from various sources that could contribute to adverse impacts on air quality.

Real-time monitoring and response to control dust at Mt Arthur Coal in New South Wales (Australia)

In the Hunter Valley, where Mt Arthur Coal is located, dust can be an issue given the proximity of large towns such as Muswellbrook, with a population of 12,000 some 2km to the north east, and the proximity to other local dust sources from mines, farming, coal-fired power stations, wood-burning heaters, as well as dust blowing in from inland Australia. As air quality standards are appropriately stringent, it is imperative that any dust generated through mining at Mt Arthur Coal is rigorously controlled and managed.

Last year, Mt Arthur Coal launched a comprehensive Dust Control System (DCS) which has transformed our dust management processes. We can now continually track dust levels through a network of 11 real-time dust and weather monitors that feed into an intelligent real-time data platform. The system triggers an alert when dust levels start to rise in a specific area. It also measures wind direction to automatically calculate the directional source of the dust. If the dust appears to be coming from the mine, there are a series of high-resolution live cameras that can be individually accessed and operated to isolate the cause, so solutions such as watering, machinery or process changes can be implemented.

By delivering real-time dust measurement and response capability, the DCS allows mine activity to be managed efficiently while preventing dust levels from exceeding regulatory requirements. The DCS has changed the way the mine operates. The Mt Arthur Coal team uses the system to determine the optimum time for blasting to ensure dust, fume and noise impacts on the local community are minimised. In the six months the DCS has been operational, there has been a significant reduction in dust alerts at the mine, with a 69 percent reduction in the month of December 2019, and zero incremental dust exceedances.

This success was recognised at the Clean Air Society of Australia and New Zealand 2019 Awards, where the DCS won the Industry Excellence Award for having a demonstrable effect on air quality. This is the first time this award has been won by a mining company. We are looking at taking this in-house technology to other BHP sites and sharing it with neighbouring mines in the Hunter Valley.