IRMA Standard for Responsible Mining (Draft 2.0)
Chapter 3.5 Noise

Background

All phases of mining can create significant noise.  These include: blasting in both open pit and underground mines; large ore and waste rock truck traffic on the mine site; noise from ore stockpiling, screening, and crushing; and, truck or rail traffic bring consumables to the mine site, and shipping product from the mine for final processing.

Studies have shown that there are direct links between noise and health. Problems related to noise include stress-related illnesses, high blood pressure, speech interference, hearing loss, sleep disruption, and lost productivity.[1]

Many noises can be moderated or partially managed by employing mitigation measures, including berms, mufflers, sequenced blasting, planning, timing, and communications.  However, effective control may be challenging due to a mine’s typically large geographic footprint, especially when a mine is located near communities.

Objectives/Intent of this Chapter

To preserve the amenity or health and well-being of nearby noise receptors, properties, and communities.

Scope of Application

Chapter Relevance:  This chapter is relevant for all mines applying for IRMA certification.

NOTES TO READERS ON MAJOR CHANGES TO THIS CHAPTER

  • Changed the allowable noise levels to refer to IFC requirements.
  • Revised requirement to measure noise types (tonal, low frequency, fluctuating and impulsive), to only requiring those types of measurements if there is a complaint that is not resolved by undertaking other mitigation measures (3.5.2.1).
  • Added a requirement regarding noise impacts on noise-sensitive wildlife populations (3.5.1.2).
  • Added a requirement related to blast noise and vibration (3.5.3.).
  • Reporting requirements were modified to require that the company provide the relevant data to stakeholders who have filed formal noise complaints, and otherwise to other stakeholders upon request.
  • The means of verification (MOV) have been removed from this version of the draft IRMA Standard. If you would prefer to review and comment on a version of the draft Standard that has the means of verification, you can download a pdf version of the Standard with MOV.
     

Noise Requirements

3.5.1.  Allowable Noise Levels

3.5.1.1.  Where there are human noise receptors that could be affected, noise from mining-related activities shall not exceed a maximum one-hour LAeq (dBA) at residential, institutional or educational receptors of 55 dBA during the hours of 07:00 to 22:00 and 45 dBA at other times, or result in a increase of more than 3 dB above background as measured at the nearest receptor off-site. For industrial or commercial receptors this maximum is 70 dBA at all times.[2]

3.5.1.2.  If an environmental analysis for the mining activities identifies a noise-sensitive wildlife population, the operating company shall develop a written mitigation plan that includes:

a. Specific actions to measure and identify whether or not wildlife populations are being impacted and, where appropriate, to monitor and mitigate noise impacts to relevant wildlife populations;

b. Participation by competent professionals in the assessment and development of mitigation and monitoring plans; and

c. Consultations with relevant regulatory agencies and stakeholders, including sharing of assessment, monitoring and mitigation information, prior to adoption of the mitigation plan.

3.5.2.  Mitigation of Noise-Related Complaints

3.5.2.1.  When the operating company receives a noise-related grievance/complaint from affected community members or other stakeholders the operating company shall consider the four types of noise identified below when assessing the complaint and possible mitigation measures.[3]  If mitigation or other actions do not resolve the complaint/problem then the decibel (dB) adjustments specified below shall apply:[4]

a. Where tonal noise is created, a correction of 5 dB shall apply to the measured dB level;

b. Where low frequency noise is emitted such that the difference between dBA and dBC measured at the boundary of the mine site is greater than 15 decibels, then:[5]

i. A correction of 5 dB shall apply;

ii. the mine shall provide independent reporting to certify numerically that low frequency noise does or does not exist;

c. Where noise is fluctuating, a correction of 5 dB shall apply; and

d. Where impulsive noise exists, a correction of 5 dB shall be assessed. This correction shall be applied based on any individual impulsive noise or any string of impulsive noise. A time constant of 35 milliseconds shall be applied to monitor impulsive noise.

3.5.2.2.  When stakeholders raise a concern or complaint about the potential effects of mining-related noise on wildlife populations, the complaint shall trigger the mitigation plan required in 3.5.1.2. The complainant shall be included in mitigation plan consultations.

3.5.3.  Blast Noise and Vibration

3.5.3.1.  Mining operations shall undertake blasting operations as follows:[6]

a. A maximum level for air blast overpressure of 115 dB(Lin Peak) shall be exceeded on no more than 5 % of blasts over a 12-month period at a sensitive place;

b. Blasting shall only occur during the hours of 07:00 or after 17:00, Monday to Saturday unless prior approval has been obtained from the appropriate government permitting agency, and prior to that permitting the public was consulted about impacts to human and non-human receptors, particularly as regarding times of day and seasonality.  In no circumstance shall blasting be allowed before 07:00 or after 19:00; and

c. A ground vibration peak particle velocity shall not exceed 5mm/second peak particle velocity for 9 out of 10 consecutive blasts and not greater than 10 mm/second peak particle velocity at any time.

3.5.3.2.  Mining operations may undertake blasting outside of the time restraints in 3.5.3.1.b. when the operating company can document that such blasting will not elicit complaints either because:

a. There are no nearby noise receptors, including wildlife potentially impacted by blasting noises; or

b. Potentially affected human receptors have given voluntary approval for the expanded blasting hours and, if there are potentially affected wildlife receptors, a competent wildlife biologist has provided his/her written opinion that such expanded hours will not adversely impact wildlife.

3.5.4.  Reporting

3.5.4.1. When stakeholders make a noise-related complaint, the operating company shall provide relevant noise data and information to them. Otherwise, noise data and information shall be made available to stakeholders upon request.

Cross Reference to Other Chapters

 Chapter

 Issues

1.1—Legal Compliance As per IRMA Chapter 1.1, if there are host country laws governing noise from mining operations, the company is required to abide by those laws. If IRMA requirements are more stringent than host country law, the company is required to also meet the IRMA requirements, as long as complying with them would not require the operating company to break the host country law.
2.2—Occupational Health and Safety Chapter 3.5 pertains to the impacts of mine-related noise on local communities and wildlife. The impacts of harmful noise on workers are covered in Chapter 2.2.
2.8—Community and Stakeholder Engagement Consultations with stakeholders related to the development of noise mitigation plans shall conform to the stakeholder engagement requirements in Chapter 2.8.  Reporting shall conform with the Communications and Access to Information requirements in Chapter 2.8.
2.13—Grievance Mechanism and Access to Other Remedies Noise impacts not anticipated in the ESIA or not adequately mitigated may result in complaints by stakeholders. As per Chapter 2.13, the operating company is required to have an operational-level grievance mechanism available to stakeholders, including procedures for filing mining-related complaints, and having those complaints recorded, investigated and resolved in a timely manner.
4.1—Environmental and Social Impact Assessment Potential noise impacts, such as impacts on sensitive wildlife species, may be identified in the ESIA. The assessment may result in the development of mitigating strategies for noise.

 

Endnotes

1. For example, see various documents on US EPA Noise Pollution Clearinghouse website; Also, see various publications on World Health Organization website.

2. ibid. pp. 52, 53 and Table 1.7.1.

3. While most discussions about noise focus on volume, impacts from noise are largely controlled by four factors that can increase the health impacts or annoyance factors associated with noise. The Industrial Noise Policy developed by the NSW Environment Protection Authority provides more information on the four noise types that can contribute to intrusive noise impacts. and decibel adjustments to protect noise amenity. IRMA Guidance will provide more background and resources related to this requirement.

4. The decibel “correction” shall apply to account for the special impacts that occur from special types of noise. The correction shall be added to the measured dB level before that dB level is compared to the acceptable dB noise level of the IRMA or host country noise standard.  Where a correction is applied, the uncorrected dB level shall be reported parenthetically. The total correction applied for 3.5.2.1. a, b, c and d shall not exceed 10 db(A).  

5. If the mine site includes more than one source of low frequency noise that triggers this requirement then the subpart shall apply individually for each of the sources on the mine site.

6. These requirements are based on the Australia and New Zealand Environment Council’s “Technical basis for guidelines to minimise annoyance due to blasting overpressure and ground vibration.” ANZEC, 1990.

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