miner underground with vehicle

Reducing harmful air emissions in underground mining

Two of the biggest threats to the health of our people working underground are from air emissions generated during the mining process: diesel exhaust from machinery, which contains diesel particulate matter (DPM), and coal mine dust.

The BHP Mitsubishi Alliance Broadmeadow underground metallurgical coal mine in Queensland has made significant advances towards eliminating potential worker exposure to both of these substances, significantly enhancing management of associated risks to the health of our people.

Broadmeadow is also an early participant in BHP’s Group-wide real-time emissions monitoring program, which promotes the use of real-time monitoring technology to assess potential worker exposure to these substances and to verify the effectiveness of controls.

Towards eliminating DPM exposure

Exposure to DPM (a Group 1 carcinogen) can pose a risk to the health of our people at the Broadmeadow mine. The Broadmeadow team is working towards eliminating our workforce’s potential exposure to DPM and, to date, has approached this goal in four stages:

Workforce engagement

The team began by implementing a DPM awareness campaign among mine workers to help identify improvements and increase the general discussion on how we can eliminate the risk of exposure to DPM.

Emissions-based maintenance

With the workforce engaged, the team introduced an emissions-based maintenance project for the mine’s underground vehicle fleet. Maintenance activities relevant to DPM emissions were reviewed and exhaust DPM limits set that vehicles had to pass to be put back into service; failure to meet these limits triggered further maintenance. This led to a 40 per cent reduction in DPM emissions from machinery used in the underground environment.

Other options considered at this stage included the investigation of alternative fuels, a DPM health check and exhaust filtration.

The Hino engine replacement project

After successfully reducing emissions through revised maintenance practices, the team worked with a local company to develop a low emissions engine for the Broadmeadow underground fleet. The new ‘Hino’ engine was installed across the fleet, resulting in a further 70 per cent reduction in DPM emissions from each underground vehicle. This stage of the project had the additional benefit of supporting a local manufacturer to develop and build the new engine.

Beginning the move to electric vehicles

While stages 1 and 2 led to a significant reduction in DPM emissions, the team determined the only way to eliminate DPM emissions entirely was to move away from diesel-power for underground vehicles. The team was unable to identify a lithium-ion powered (LIP) electric mining vehicle supplier in Australia, but found a manufacturer in Canada and worked with them to develop a tailored underground-approved electric vehicle for coal mining. The Broadmeadow team worked to enable the vehicle to be certified for use in most of the underground districts of the mine.

Trials of the LIP electric vehicle in the underground environment were successful and Broadmeadow has subsequently acquired a further three electric vehicles, all of which produce no DPM emissions. Work continues to reduce and, ultimately, eliminate our workforce’s potential exposure to DPM at the mine.

Reducing coal mine dust exposure

Exposure to respirable coal mine dust can adversely impact the health of our people. Coal workers’ pneumoconiosis (CWP), commonly known as Black Lung, is one of the potential risks. Broadmeadow has made reducing the potential exposure of our workforce to coal mine dust one of its highest priorities.

Our approach is to use technology to remove workers from the coal face, eliminating their exposure to underground coal dust and also eliminating the risk of injury from flying debris during the mining process.

The project has shown it is possible to successfully automate key underground mining roles. An added advantage of this change is to make these tasks less physically demanding, which not only reduces the risk of musculoskeletal injury to our people, it also enables them to be undertaken by a worker on light duties.

Eliminating a proportion of our workforce’s exposure to underground coal dust at Broadmeadow was addressed in three stages:

Design and build of a Controlled Atmosphere Remote Operating Station

Firstly, the frontline teams at Broadmeadow challenged the automation team to come up with a solution to remotely operate roof supports at the mine’s longwall coalface. They engaged an original equipment supplier and, together, developed software that enabled safe operation of roof supports remotely.

Secondly, they implemented this technology and housed it in a Controlled Atmosphere Remote Operating Station within the mine, removing the operator from the source of underground coal dust while working in the Station. There was also an operational benefit to this as remote operation enabled the coal shearer machine to continue to operate while the roof supports were being advanced. This was not possible when the roof supports were required to be moved manually.

Roof support operator relocated to the surface of the mine

In the third stage, the team overcame the technology challenge of communication latency issues and established a Remote Operating Station on the mine’s surface. They were able to ensure the communication link from surface to underground was robust and could communicate effectively over a long range. This meant the roof support operator no longer has to work in the underground mine, eliminating any further risks associated with the underground working environment. Broadmeadow was one of the first to use this technology consistently in Australia.

The project has been successful and has not only eliminated exposure to underground coal dust for the roof support operator on the longwall, it has delivered additional benefits such as:

  • Better risk management – it has removed the roof support operators from an underground working environment entirely, eliminating exposure to the risk of injury from flying debris that can break off during the mining process and has reduced the risk of musculoskeletal injury by making tasks less physically demanding
  • Production improvements – there are no longer stoppages to allow the roof support operator to perform essential work in the ‘no go’ zones
  • Improved risk culture – it has created a positive shift in how the workforce thinks about effectively managing the risk of exposure to coal mine dust, with a focus on risk elimination over reduction where possible
  • Better injury management – workers on light duties can undertake the roof operator tasks from the surface, which can help with their return to work
  • Industry benchmark – this approach is easily replicable in underground coal mines worldwide.

For further information, please see Praise for Broadmeadow Mine dust and particulate matter reduction program.

Real-time emissions monitoring

Broadmeadow is one of the first BHP mines to pilot a new real-time mine emissions monitoring system. This technology has also been introduced at our Escondida operations in Chile and Western Australia Iron Ore’s Whaleback mine.

The new technology enables emissions such as DPM and coal mine dust to be tracked in real time and allows additional controls to be implemented, where appropriate, to support controls already in place to manage the risk of worker exposure to these emissions.

The real-time data can be analysed and accessed across a range of mobile devices, and has the capability to issue automatic alerts and alarms to further protect our workers.

BHP is in the process of extending this capability to a further 11 mines. This real-time monitoring capability is critical to support the identification and implementation of controls required to meet our public five-year (FY2018-FY2022) health target relating to the reduction of our workforce’s potential exposure to DPM, respirable silica and coal mine dust.