Essential blasting and environmental controls for surface mines

​On 2 August 2024, the Department of Mineral Resources and Energy (DMRE) published new guidelines for the mandatory Code of Practice (COP) concerning ground vibrations, noise, air-blast, and flyrock near surface structures and communities (Guidelines) that will become effective on 1 November 2024.

The Guidelines reinforce and clarify existing duties under Regulation 17 of the Mine Health and Safety Regulations. Section 9 of the MHSA mandates that employers at every mine must prepare and implement a COP on matters affecting the health and safety of employees and other persons directly impacted by mining activities and Regulation 17, specifically, deals with the responsibilities of employers regarding safety precautions near surface structures.
Regulation 17(5) of the Mine Health and Safety Regulations requires employers to ensure that a competent person responsible for mine surveying is aware of the progress and impact of mining activities on surface structures. It mandates the monitoring of various conditions that could pose risks, such as workings being advanced towards surface structures.

Regulation 17(6) further obligates the employer to notify the competent person in writing of any mining operations coming within specified distances (100 metres or 50 metres) of surface structures, roads, or other places that require protection. Regulation 17(7)(a) reinforces this by stipulating that no mining operations should occur within 100 metres of such structures unless a risk assessment has determined a lesser safe distance, with all associated restrictions and conditions being adhered to.

Under Section 9(2) of the MHSA, an employer is required to prepare and implement a COP on any matter affecting health or safety when mandated by the Chief Inspector of Mines (CIOM). The new guidelines function as a mandatory COP under this section, meaning that failure to prepare or implement a COP in compliance with these guidelines constitutes a breach of the MHSA. Section 9(3) of the MHSA clarifies that any COP must comply with the relevant guidelines issued by the CIOM. Thus, these guidelines are not creating new obligations, but are setting the framework within which the requirements of Regulation 17 should be interpreted and applied, ensuring that all mining operations adopt a consistent approach to managing the risks associated with blasting.

The Guidelines introduce minimum standards for managing ground vibrations, noise, air-blast, and flyrock in surface mining operations. These standards were developed in response to growing concerns from communities affected by blasting activities, where damage to buildings and other structures is alleged to be attributed to mining operations.

Much like the empowering provisions of the MHSA, employers must identify and assess risks affecting both employees and non-employees, with the COP addressing how to eliminate, control, and minimise these risks. Risk assessments should consider all relevant information, and the COP must be reviewed after incidents, accidents or significant changes in procedures are introduced. The guidelines outline the specific measures to be included in the COP for the management of ground vibrations, noise, air-blast, and flyrock which include:


  • pre-survey requirements;
  • drill and blast design;
  • quality assurance and quality control;
  • monitoring and recording of actual blast results; and
  • community engagement, in particular management of complaints.

Before any blasting operations commence, a detailed pre-survey of surface structures within the affected area is required. This survey must assess the condition and structural integrity of these structures and establish baseline limits for ground vibrations and other risks. This directly supports Regulation 17(6) by ensuring that employers are fully informed of the potential impacts of mining activities on nearby structures, however, the pre-survey contemplated in the Guidelines focuses on the identification and protection of structures that may be affected by blasting activities in particular. In cases where blasting has already started without a prior survey, such as at existing mines, a survey must be conducted immediately following the effective date of the Guidelines.
The data gathered from these surveys must be used to establish site-specific baseline limits, restrictions, and conditions. These parameters will help manage ground vibrations, noise, air-blast, and flyrock, ensuring there is no significant risk to the identified structures or the health and safety of individuals within the affected area.

The objectives of the pre-survey are to determine the specific structures that need protection. These could include public buildings, thoroughfares, railway lines, power lines, or any other location where people congregate or that require safeguarding; determine the condition and structural integrity of the identified structures; and measure the distance between the blasting site and the identified structures. The extent of the obligation to determine the structural integrity of such structures may prove onerous where the deterioration of infrastructure may be attributed to other factors beyond the mine operator's control or scope of influence and where the structural integrity of the structures is unknown or not anticipated, particularly in the case of informal dwellings. In this regard, the principle of "who came first" will apply which means that measures must be put in place to protect structures that existed prior to the commencement of blasting operations, while structures built after the commencement of such blasting should be designed and built to withstand exposure without sustaining undue damage provided that the mine operator effectively communicates the prescribed safety limits to nearby communities seeking to erect new structures.

The guidelines require the development of site-specific blast designs by a multidisciplinary team whenever there is a significant risk to structures. The multi-disciplinary team must include a qualified blasting expert, the relevant explosive manufacturer or supplier, a geologist, a rock engineer or geotechnical expert with a Chamber of Mines Certificate in Rock Mechanics, an employee representative, and a representative from the affected community. This team is tasked with designing a drill and blast plan that limits the impact of ground vibrations, noise, air-blast, and flyrock to levels below the recommended South African standards, as outlined in the Guidelines (noting however that there are no acceptable levels of flyrock outside the mine site or the designated exclusion radius).

The provisions for quality assurance and control require the mine operators to establish practical and reasonable systems to ensure every blast is executed as designed. Alongside these systems, the employer must also implement an effective monitoring system, such as the use of vibrometers (designed to measure mechanical vibrations in machinery and structures), to track and record the intensity of every blast with respect to ground vibration, noise, air-blast, and flyrock. The specific location of monitoring equipment is determined during the required risk assessment and documented on a plan tailored to each blast site. Following the blast, the predicted design values must be compared with the actual results. Any deviations must be investigated, with their impacts thoroughly evaluated to prevent future reoccurrences.

In recognition of the impact of blasting on nearby communities, the guidelines also call for greater communication between mining operators and affected communities. This aligns with the principles of Section 5(2) of the MHSA, which requires employers to ensure that non-employees are not exposed to hazards resulting from mining activities. Mine operators are required to establish and implement effective measures to register and address complaints from surrounding communities and other affected parties. In addition, the COP must include steps to raise awareness through posters and consultations with community committees, as well as implementing a warning system at the mine to forewarn of any blasting taking place, such as audible alarms, sirens, posters, blast notification boards, and WhatsApp messages to ensure all affected parties are informed.

In the preparation, implementation, or revision of the COP, employers must consult with the health and safety committee or an employee representative. A drafting committee, including competent persons, should be appointed after consultation with employees, and the members' details should be documented in the COP. The mine operator must develop a plan for implementing the COP, detailing responsibilities, structures, and schedules. In addition, visual aids such as graphs, illustrations, and tables, should be used in disseminating information required in COP to facilitate easier interpretation of data and trends to conduct risk assessments.

It is essential for mining companies to understand that these guidelines reinforce the existing framework within which they must operate. Compliance with these guidelines will help ensure that mining operations are conducted safely, with due consideration for the surrounding environment and communities.

As the effective date of these Guidelines approaches, it is advisable for all mining operators to review and, where necessary, update any associated COPs to ensure they are fully aligned with the latest standards and best practices. Employers are encouraged to consider the Guidelines and take the necessary preparatory steps, particularly in respect of conducting pre-surveys and surveys. Webber Wentzel's occupational health and safety team is assisting clients review, update and draft the necessary COPs. If you require any assistance with the preparation of the same or advice on any of the guidelines, please reach out to our occupational health and safety lawyers or your usual Webber Wentzel contact.

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Disclaimer

These materials are provided for general information purposes only and do not constitute legal or other professional advice. While every effort is made to update the information regularly and to offer the most current, correct and accurate information, we accept no liability or responsibility whatsoever if any information is, for whatever reason, incorrect, inaccurate or dated. We accept no responsibility for any loss or damage, whether direct, indirect or consequential, which may arise from access to or reliance on the information contained herein.


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