Mining Noise: Optimizing the Social Acceptance of Mining Projects Through the Successful Management of Noise Emissions [Guide]

Mining Noise & Social Acceptance [Practical Guide]

For Community Relations and Environmental Management Teams

  Introduction  

Optimizing the Social Acceptance of Mining Projects Through Proactive Control of Mining Noise Emissions

Due to the nature of mining activities, the concerns most often raised by communities near mining sites generally include noise, vibration, and dust. 

The growing importance of the social acceptance of projects stems directly from the potential impact on the quality of life that may be experienced by residents in the neighbouring communities. Whether it is the noise generated by mining activities, or the proximity of mining exploration activities to the community, the noise generated by the mine can not only have significant consequences for local communities, but can also jeopardize the very feasibility of the project.

Therefore, it is essential to take potential noise impacts into account at every stage in the development of a mining project. Doing so, will reduce the risk of generating noise pollution, safeguard the health and well-being of local communities, and ensure the sustainability of mining operations.

What Are the Noise Regulations in Canada?

All mining operations must comply with federal, provincial and local noise regulations and standards. There are different regulations that are applied in each Canadian province. Directive 019 in Quebec and NPC-300 in Ontario are examples of provincial regulations and guidelines that must be adhered to in order to obtain necessary permits to operate.

In Ontario, the Noise Pollution Control (NPC) documents are a set of guidelines published by the Ontario Ministry of the Environment, Conservation and Parks (MECP). These guidelines are applicable to the mining industry in Ontario, and aim to establish limits, measurement procedures, and assessment methods that are to be applied during the approval and planning process of the mine. The implementation of the NPC guidelines is to ensure that noise (NPC-300: Stationary and Transportation Noise Sources) and vibration impact (NPC-119: Blasting) on nearby sensitive lands is minimized and do not cause an adverse effect, as defined by the Ontario Environmental Protection Act (EPA). The limits and the assessment methods for noise & vibration are detailed in NPC-300 and NPC-119, as well as the supplemental documents NPC-101: Technical Definitions, NPC-102: Instrumentation, NPC-103: Procedures, and NPC-104: Sound Level Adjustments.

Achieving these standards is critical, not only to comply with legislation and maintain the mine's operating permit, but also to avoid various obstacles to project development, which could have a negative impact on project completion.

But is compliance with noise limits enough to ensure the social acceptance of a project?

In this guide, our engineers highlight other essential acoustic considerations to help ensure the social acceptance of a mining project.

  Chapter 1  

Acoustics 101 — Fundamental Concepts You Need to Know to Help Mitigate Mining Noise Issues

Before addressing and minimizing the mining noise issues commonly encountered during the various stages of a mining project, it is essential to master certain basic notions of acoustics.

1. Regulatory Compliance vs. Audibility: Being “Compliant” Does Not Equate to Being “Inaudible”

How Is Regulatory Compliance Assessed?

The specific method for determining compliance varies based on the jurisdiction in which the mine is located. In general, a mine's noise compliance is assessed by taking measurements over a period of time in various areas surrounding the mine.

In accordance with regulations, the results of sound measurement levels are usually averaged over a predefined period of time, such as 1 hour, 24 hours, etc. This may be suitable for operations with steady operations and relatively stable noise emissions. However, for operations with variability, the measurements of the instantaneous sound levels may vary significantly over this time period. Given this variability, levels may be higher or lower at certain times. Additionally, the measured sound levels may also include various environmental sounds (e.g. cars, wildlife, human activities, etc.). These noise compliance measurements are therefore, often not representative of the mine's perceived noise contribution.

To summarize, a noise compliance assessment, which is based on an average sound level over a period of time, often does not account for short-term noise fluctuations and may not provide an accurate representation of the mine’s perceived noise emissions.

In addition to the assessment period, these regulations are generally based on a noise target (numerical value) to be met, such as an ambient noise level, or a fixed noise level when the ambient level is too low. The ambient noise level is the noise that is existing in the environment, without contribution from the mine.

“Compliant”, Yet “Audible”?

Understanding the difference between "noise compliance" and "audibility" is essential for community relations and environmental teams. Although mining activities may be compliant, they can sometimes be audible and cause a nuisance for the neighbouring communities.

Fortunately, various strategies can be put in place to minimize the impact of noise contribution from mining.

 

Let’s face it, there’s no such thing as zero noise emissions from a mining project. It's impossible to design a mining project without generating a certain degree of noise.

So, what is the best strategy for ensuring harmonious community relationships?

We will address that shortly, but for now, let's continue with a few basic notions of acoustics, which will give us a better understanding of the concepts needed for effectively managing mining noise complaints.

2. Types of Noise that May Increase Community Complaints

Noise complaints are not only caused by an overall increase in noise levels. In the case of mining projects, there are typically specific noises that are the source of disturbance for neighbouring communities.

Beyond the project noise contribution and ambient noise of the sector, many factors can also influence noise perception, such as the characteristics of the noise emitted.

 

 

Here Are Some Common Examples of the Types of Noise and Their Sources at Mining Sites:

Continuous noise: This type of noise is generally associated with equipment that is in constant operation, with low noise variability, such as crushers. It is characterized by a continuous, stable sound emission over an extended period. Other examples of continuous noise sources are ventilation systems, pumps, baghouses and other rotating equipment that is in continuous operation.

Continuous noise of a crusher

 

Sporadic noise: Unlike continuous noise, sporadic noise is produced by specific, intermittent activities; such as trucks unloading, or travelling along haul roads and the stopping and starting of certain equipment. The sound may be brief, but its contribution may be higher during this period, making it more noticeable.

Sporadic noise from a tracked excavators

 

Impact noise (impulsive): Certain noises can also be "impact noises", since they can lead to a short, but significant increase in noise levels. A good example of impact noise is a hydraulic hammer.

Impact sound from a hydraulic hammer

 

Tonal noise: This is noise that is continuous in which most of the acoustic energy is centered around a particular frequency, as in the case of certain mining fans. If you can hum or whistle the sound, it’s most likely a tonal sound.

Tonal noise from a mining fan

 

Low-frequency noise: This is a noise that is mostly concentrated in low frequencies and tends to carry over much longer distances. This type of noise can resemble a “rumbling” sound and may sometimes cause objects to shake or rattle (e.g. windows, picture frames, etc.) and therefore often gets mistakenly identified as vibrations.

Now we know that noise sources that can cause disturbances are not necessarily the loudest.

The average noise contribution of a screening plant may actually be greater than that of a truck unloading operation. However, since the noise from the screening plant is continuous and the human ear has gradually adapted to this type of noise source, the screening plant is likely to become less perceptible than a truck unloading operation. Therefore, unloading trucks will be more likely to produce noise complaints from the surrounding communities.

3. The Nature of Noise Should be Considered when Managing Complaints

The perception of noise is largely based on the nature of the noise.

For example, if crickets were to emit a sound of 60 dBA in the middle of nature, this may be quite tolerable, even pleasant. On the other hand, the sound of an excavator producing only 40 dBA in the middle of the night, will likely be perceived as more disturbing, as we typically expect to hear the natural sounds of wildlife, not those of mining equipment.

→ Therefore, the nature of a noise is a factor that needs to be taken into account in acoustic monitoring projects for mining sectors.

  Chapter 2  

The Different Phases of a Mining Project, Their Respective Noise Challenges and How to Avoid Them

Now that we're familiar with some of the fundamental concepts in acoustics, let's explore the noise issues inherent in each phase of a mining project, putting forth effective measures to prevent mining noise nuisance and minimize the risk of noise complaints.

Mining projects are generally divided into five phases: 1) Mining Exploration, 2) Authorization, 3) Construction, 4) Operation, and 5) Rehabilitation.

Mining Exploration

A Common Situation that Raises Noise Issues and Often Leads to Complaints

During the exploration phase of a mining project, equipment such as drill rigs, pumps and generators generate noise, and sometimes around the clock. In addition to being noisy, they are often located in quiet natural environments, in close proximity to communities.

Have you done the math?

Noisy equipment + operating close to residential areas + relatively low ambient noise (to which the human ear has adapted) = recipe for unwanted noise, increased likelihood of noise complaints and community opposition of the project.

Although exploration activities are generally of short duration compared to other phases of a mining project, they can still produce a significant noise disturbance. Excessive noise frequently leads to complaints, and can even bring operations to a halt.

Authorization Phase — Environmental Impact Study (Noise Section)
 

Before constructing a mine, it is essential to fully understand the surrounding noise environment, to know the noise trends, and to assess the area adequately. For example: How does the noise environment in the project area vary from day to day, evening to evening, weekday to weekend, season to season, and in various weather conditions, etc.? What impact does the noise environment have on the community?

Surrounding yourself with experts in acoustics and vibration will help you design your mining project more effectively and successfully.

An inadequate assessment of the noise environment in the authorization phase, can often lead to additional noise issues during subsequent phases and may even result in exceedance of noise regulations. Hence, the importance of properly assessing the noise environment in the early stages.

Note that modeling alone doesn't always provide a clear picture of what is perceived as disturbing, as it is generally based on averages. While this is not impossible, at Soft dB, our acoustic engineers have developed unique techniques for tackling this complexity.

How to Properly Address Noise During the Authorization Phase to Avoid Noise Complaints in Subsequent Phases

• Conduct noise environment measurements over long durations in order to obtain a more complete understanding of the noise environment at various times of the year.
• In order to obtain a certificate of authorization, it is essential to carry out an environmental impact study demonstrating that mining noise compliance can been achieved, by identifying any potential noise sources (with precision), and using effective solutions, all while optimizing costs to achieve the objectives set. If you need help, our experts in acoustics are available to support you in this process.

 

Construction and Operation of a Mine Site

Common Causes of Noise Issues and the Strategies to Address Them

Even after an application for authorization to build and operate a mining project is approved, once the project is in its construction and operation phases, you may still receive numerous complaints and opposition from neighbouring communities due to mining noise.

Why is this the case?

Construction Phase

During the construction phase: New sounds become audible in the community. The sounds that residents were previously accustomed to hearing during earlier phases of the mining project have changed.

• Residents are hearing new, sporadic, and variable noises, which differ from day to day.
• These noises are generally produced by mobile equipment, whose noise contribution can vary greatly from one moment to the next depending on their location and activity.
• These activities take place mainly during the day, with noise levels increasing in the morning and decreasing at the end of the day.

The noise now being emitted from the construction operations has become the residents’ new reality and in order to maintain a positive relationship, it is important to take their concerns into consideration.  

Operating Phase

During the operating phase: the noise environment changes once again.

• Presence of new noises (e.g. drilling, blasting, mine ventilation, etc.). These sound sources generally have specific acoustic characteristics, which often make them more perceptible.
• Most sound sources are now operating continuously, 24/7.

Generally speaking, these are the most common causes of noise complaints due to changing sounds in the environment:

 

1) The theoretical study (Noise Impact Assessment) underestimated your actual mining noise contribution:

In the field, the equipment that was chosen may differ from what was modeled during the noise impact study or during the detailed engineering phase; hence the importance of conducting a thorough initial noise study. In addition, certain factors, if not taken into account (e.g. weather conditions such as wind direction, temperature inversions, etc.) can affect sound propagation and may have a significant impact.

 

2) You are compliant, but audible: 

a.    The existing ambient noise may be lower than the noise targets considered in the study, due to measurements taken over a short period of time. Low ambient noise, i.e. noise in the environment without mining activities, increases the likelihood that the mining noise activities will be audible in the surrounding community.

b.    The ambient noise level may be higher, but some specific noises, such as impact sounds, tonal sounds, low frequencies, etc., are audible. As indicated in many regulations, these types of noises often require the addition of a penalty to compensate for the enhanced perception (and thus annoyance) of these sounds. For example, the sound of an excavator may last for a brief moment, yet rise above the ambient noise and be clearly audible. However, if the overall sound is averaged over an hour, its contribution may be negligible.

How to Minimize Impact During Construction and Operation Phases

To put yourself in the shoes of the community and fully understand their reality, a high-performance noise monitoring solution incorporating continuous sound recordings is a first-rate solution. 

If a sound monitoring system only allows you to measure a single metric, say 30 dBA overall, how do you determine the cause of a complaint, identify audible noises or even know your noise contribution when you are within compliance?

Typical Situation Leading to Mining Noise Complaints Regardless of the Phase of the Mining Project

 

  Chapter 3  

Noise Monitoring With Continuous Audio Recording: Your Solution of Choice for Mining Noise Complaint Management

  Chapter 4  

Why Continuous Noise Monitoring is an Important Tool in the Social Acceptance of a Mining Project

Mining projects are not always situated in close proximity to communities. They may be located in a quiet environment, where ambient noise is low, and sound levels may vary on a daily basis, according to weather conditions, natural sounds, wildlife, human activities, etc. For example, for a source located at a distance of one kilometer from a residence (referred to here as a "receptor"), the presence or absence of winds between the source and the receptor can lead to drastic changes in the sound environment.

Noise Monitoring Prior to the Start of Mining Activities

For a mine, continuous noise monitoring may be relevant prior to construction activities, in order to establish the ambient noise level, enabling a comparison of noise contributions before and after the start of operations.

It also helps to assess and document potential community relations issues as well.

By installing permanent noise monitoring stations, depending on the ambient noise levels measured, adjustments can be made to mining activities. For example, if the existing ambient noise was 27 dBA and the mining activities increase the level to 38 dBA, even if this complies with regulatory limits, it can be audible and therefore may be disturbing for some residents, as the noise level would be perceived as being twice as loud. 

Continuous sound monitoring adds value to the understanding of the situation.

Pro Stations for Community Relations Management

The noise and vibration monitoring stations such as the Watch™ and the Pro Stations developed by Soft dB, are specifically adapted for community relations management.

Soft dB’s noise monitoring stations offer exceptional audio quality with a built-in weather module, handy for filtering out sound events caused by extreme weather. They are strategically positioned in the field by our team that specializes in data analysis and processing. See our range of noise monitoring services.

In order to be able to filter through all of the collected data and be able to better understand the causes of noise complaints, it is often necessary to perform acoustic signature and noise level analyses. This requires analysis of the frequency content of the signal, either via a Fourier transform or a one-third octave band representation. 

These advanced tools make it possible to represent the distribution of frequencies contained in a sound signal.

→ Soft dB noise and vibration monitoring stations enable this type of analysis in real time, and allow users to go even further in analyzing complaints and understanding noise issues.

This practical guide incorporates knowledge and observations drawn from thousands of Soft dB projects in the mining sector.

As each project is unique, it is important to emphasize that this guide cannot replace the specific analyses of a qualified acoustics and vibration expert.

All projects must be assessed on a case-by-case basis.