Ground vibration
Ground vibration can be induced by a number of external factors other than blasting. External events such as thunderstorms, heavy vehicle traffic on roads and seismicity all have the potential to generate vibration within a structure. Human activities within a structure can also induce vibration.
Ground vibration from blasting
Blasting is commonly used in the mining industry and involves the controlled use of explosives to break/fracture solid rock. Each firing is designed and planned by a Drill and Blast Engineer with a focus to ensure optimal rock breakage and performance, whilst minimising ground vibration and disturbance to community. There are two types of firings undertaken at Fosterville Gold Mine: development, which are smaller and production firings, which are bigger.
Ground vibration and the associated noise from blasting is caused by the release of energy associated with the detonation of explosives.
Vibration waves generated at the blast site travel through the earth in different directions. These waves dissipate in intensity the further they travel.
At Fosterville Gold Mine production and development firings can occur 24 hours a day, 7 days a week.
FGM monitors ground vibration using a network of geophones installed on the surface.
Ground vibration levels at FGM are currently regulated by Earth Resources Regulation. Limits for blast vibration are part of FGM’s mining licence conditions.
Blasting and community
The experience of blasting at FGM can vary significantly from resident to resident. Individuals also have varying levels of sensitivity to ground vibration and noise generated from blasting.
FGM acknowledges the potential impacts to community from its blasting activities, and has developed a number of initiatives to manage its effects including:
- SMS blast notification prior to all scheduled production firings.
- Online survey form made available for residents to provide instant feedback on blast events.
- Baseline building inspections and structural assessments, where appropriate.
- Temporary blast monitor installations at landholder’s request.
- Third party review’s of FGM’s blasting practices and blast monitoring network to review and identify opportunities for continuous improvement.
Feedback on FGM’s blasting activities is critical in understanding landholders experience of blast events and informing our decisions to manage any impacts on the community.
Ground vibration from mine induced seismicity
Underground mining changes the pressure and distribution of forces (stress) applied to the rock being mined. The extraction of rock reduces pressure in some areas and increases pressure in other areas.
Under certain conditions these stress changes lead to the rock fracturing, which in most circumstances is near the void where rock has been created.
When rock fractures energy is released as ground vibration. This form of ground vibration is called mine induced seismicity (MIS).
The occurrence of seismicity is not new to FGM and is a common phenomenon across the mining industry. The magnitude and frequency of MIS events has increased over time at FGM due to increasing levels of stress, as the mine extends deeper underground.
Monitoring MIS
FGM maintains a dedicated underground seismic monitoring system to identify and monitor MIS events. This monitoring system enables FGM to record when an event occurs underground, the magnitude and location of the event. Magnitude is commonly used to report the size of both mine induced seismic events and earthquakes.
Occasionally, mine-induced seismic events will be recorded on the surface and may trigger FGM’s surface vibration monitoring network.
If you experience a ground vibration event and would like further information, please contact the FGM Community Team and we will be able to advise whether it was related to FGM’s operational activities.
Underground safety
FGM implements underground safety systems and procedures that cater for mine induced seismic events. Immediately after a new void or tunnel is mined, specialised mining equipment is used to install ground support to ensure the safety of workers in the area. Long rock bolts, mesh, steel plates, cables and concrete are all used to secure the open ground and maintain stability. The ground support has dynamic capacity to resist damage from seismic events.
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Services available to neighbouring landholders
Blast Notifications
Fosterville Gold Mine has implemented an SMS Blasting systems which send community members SMS notifications in advance of planned production firings. Please register to receive an SMS notification.
Blast Notifications
Baseline Building Inspection
If you are concerned about impacts to your property as a result of ground vibration FGM can arrange for a baseline building inspection to be completed by a third-party specialist engineer. The inspection will identify and record the current condition of the house as a baseline for future change.
The inspection is carried out by Terrock Consulting Engineers and a detailed report is provided to you on completion.
Baseline Building Inspection
Ground Vibration Monitoring
Ground vibration monitoring can be undertaken at your property for a period of three months. The potable monitor will be installed in a suitable location near your house with results provided at the conclusion of the monitoring period.
Ground Vibration Monitoring
Rainwater Tank Sampling
To learn more about water monitoring or to register for rainwater tank sampling, click the button below.
Rainwater Tank Sampling
