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On 5 November 2024, a 3.4 seismic event associated with Fosterville Gold Mine was felt by many of our neighbours, causing considerable concern. Community members shared their experience of the event, and in so doing, provided us with a better understanding of its impact. It is clear that the unpredictable nature of mine-induced seismicity is unsettling, and we take this seriously.

Following the seismic event, we voluntarily paused all blasting activities, while investigations were completed. This resulted in a carefully planned and staged approach to the resumption of blasting and underground mining activities over multiple months.

Each stage involved:

• an extensive review of the mine plan and existing practices; sequencing and tactical measures with input and assessment of a range of controls to manage the risk of seismicity, including advice mine design, expert review and advice; and
• acknowledgement from the Earth Resources Regulator (ERR) before resuming blasting activities.

To further strengthen our approach, we engaged external expertise from Beck Engineering – specialists in mining and rock mechanics analysis for the global mining industry – to complete a comprehensive review of geological settings, structural conditions and provide advanced modelling. Their insights, along with our onsite expertise, enable us to maintain the highest safety standards and operational excellence, by building on our industryleading practices in managing seismicity.

In order to keep everyone informed about the extensive work that has been undertaken, we have included below a detailed overview of the staged approach taken since the 5 November 2024 seismic event:

Stages 1 & 2: Resuming work in areas of low seismic risk

We began by focusing on areas with naturally lower seismic risk:

• Shallower areas: We resumed work in shallower areas such as Robbins Hill and Harrier, where the natural rock ‘stress’ is significantly lower. As we mine deeper, the weight and pressure of the overlying rock increases. By focusing on shallower zones where the seismic potential is significantly reduced, the likelihood of generating seismicity as a result of our mining activities is reduced.
• Resumption of development blasting: We resumed the development of underground tunnels and vertical vent shafts, which by design require much smaller blasts to mine. These smaller blasts generate incremental stress changes within the surrounding rock mass, lowering seismic risk.
• Limited production blasting: We limited production blasting activities during these stages to minimise potential impact to the community.

Stage 3: Advanced techniques for complex mining areas

In this stage we focused on specific areas within Phoenix mining area, including the ‘Swan’ and ‘Raptor’ domains. These areas required a strategic approach due to their geology and depth.

Some areas within the Phoenix – particularly in the Swan domain – have an increased potential to generate seismic events for the following reasons:

• Greater depth: The deeper we go, the more stress in the rocks, increasing the potential for mine-induced seismicity (MIS).
• Stronger rock types: Unlike softer rocks that absorb energy, stronger rocks can store it and release it more suddenly during changes in stress.
• Geological structures: Faults or weaknesses within the rock have the potential to act as slip planes, making these areas more susceptible to seismic events.
• Stress from previous mining: Operational activities can influence how stress is distributed within the rock mass, sometimes resulting in higher concentrations in certain areas.

To manage these challenges effectively, we implemented enhanced measures including:

• Extensive pre-blast analysis and modelling: Before any blasting occurs, we conduct thorough analysis and modelling to assess potential seismic response.
• Multiple smaller blasts: Where safe and practicable to do so, instead of one large blast, we divided each stope into multiple smaller blasts. This allows for a smaller and more incremental change to the stress in the surrounding rock.
• Optimised stope design: We tailor the shape and size of stopes to optimise ore extraction while distributing stress across the rock mass.
• Strategic sequencing: We schedule mining of certain areas first to ensure that stress change within the surrounding rock could be uniformly distributed across other zones.
• Seismic Control Pillar: A pillar of rock within the orebody at least (45m wide) will be retained in an area that has been identified as having elevated seismic response potential.
• Continuous monitoring: Monitoring of surface ground vibration and seismicity allows us to detect unusual activity patterns and adjust our approach.
• Learning from past experiences: When planning new firings our team reviews previous blasts that have occurred in comparable locations and geological conditions to determine the most appropriate course of action.

Your voice matters!

At Fosterville Gold Mine, we are committed to transparency, prioritising safety, and taking action to minimise our impact wherever we can. We will always listen to your concerns because we care about the well-being of our people and community.

If you have any questions about our operations or would like more information, please contact our community team on 03 9439 9300 or email us at fgm.community@agnicoeagle.com. We’re here to help.

To read more about what’s happening at Fosterville Gold Mine, click here to check out the latest edition of our Community News.