Noise control at mining sites: an essential step toward harmonious production

Conducting noise surveys near mining sites is complex for many reasons, including:

• Large operating areas, often spanning several levels
• Multiple large-scale pieces of mining equipment
• Difficult climate conditions that tend to foster sound propagation, such as thermal inversions
• Round-the-clock mining operations
• Possible proximity to communities or public or private infrastructures

Effectively and proactively reducing noise at a mine site first requires assessing the noise impact generated by site operations on nearby residential areas and sensitive receptors. In some cases, specific activities are targeted, and their noise impacts are measured to develop noise control and mitigation solutions.

1. Noise impact studies

To kickstart the process, acoustics experts must characterize the noise environment of the mining project, focusing on the sensitive receptors closest to the project site. These can be residential or industrial zones, as well as protected areas designated as sensitive given the presence of wildlife or biodiversity.

Next, the noise emissions from the mining project must be assessed in the surrounding sensitive areas, prioritizing residential or inhabited areas. Measured noise levels are compared with existing noise standards to determine compliance or whether noise mitigation measures are required. A team of engineers supports the client throughout the design of mitigation measures and solutions.

2. Vibration impact studies

When setting up a new mining site, and throughout the assessment phases for potential expansion of an existing mining site, a study of the site's vibration impact must often be carried out to meet ministerial and regulatory requirements. The main source of vibration generated by both open-pit and underground mining operations is the rock blasting process, which to this day remains the most efficient and cost-effective method for in-situ rock fragmentation. Additionally, other significant sources of vibration emissions may arise, such as rock bursts—a phenomenon that occurs when stresses surrounding underground openings in deep mining operations are violently released. These events are often compared to earthquakes and can disrupt the surrounding environment and cause damage to certain structures.

Vibration impact studies carried out by BBA can easily be adapted to available information and typically involve the following steps:

1. Identify, estimate and model vibration sources from blasting activities using an empirical model.
2. If the site is in operation, historical data analysis will help calibrate the vibration prediction model. Historical data should minimally include the seismic data files, the locations of the blast or the rock burst event relative to the monitoring points as well as the maximum explosive charge detonated per delay for each of the monitored blasting events. If no vibration measurements are available at the time of the study, an instrumentation and measurement program will be proposed. Baseline studies are often recommended for new mining operations to better understand and manage existing stresses.
   
3. Recommendations are made based on the vibration predictions making it easier to control vibration levels generated by blasting events. These recommendations serve as a guide for adapting blasting parameters based on blasting location and proximity to sensitive areas.
4. At the start of mining operations, vibration data will be collected and progressively compiled to build a site-specific vibration prediction model. Early integration of this type of model in the production process will allow the optimization of mining operations tailored to the sensitive surrounding environments.
   

3. Acoustic simulation

Specialized software is used to visualize the noise impact of the mine site on the environment (calculations are based on ISO9613-2:1996). This process entails identifying and characterizing the noise sources from each mining activity. This is achieved through onsite measurements or using known data for each piece of equipment (acoustic power, location, areas and times of activity, etc.). Finally, parameters, such as site topography, soil absorption and atmospheric effects, are factored into the simulations.

The figure below depicts a noise map. It illustrates the sound level curves that mark out the noise zones around the noise sources being studied.

4. Mitigation solutions

If noise criteria fail to meet standards near the site, the team of acoustics experts can propose solutions to mitigate the noise impact generated by activities. These solutions must be adapted to the equipment and geotechnical conditions of the mine site.

BBA is here to meet the needs of mining companies, ensuring greater protection of the noise environment and quality of life of communities during site operations. Reach out to our experts for your noise and vibration impact studies!