On June 22, a professional webinar on the latest innovations in mine site revegetation in Africa, organized by MORFO, a company specializing in large-scale reforestation, was held. During this webinar, our experts and guests shared their knowledge and expertise on the challenges and solutions related to mine site revegetation in Africa.
The panelists were :
- Pascal Ettien Anokan
With 15 years' experience in the mining sector, he is Chairman of the HSE Commission and the Mining Sector Safety Committee at GPMCI.
- Brandet Lissambou
Okouma biodiversity manager at ERAMET COMILOG.
Managing Director at Geo guide, 36 years' experience in the mining industry.
President and founder of the NGO AEIE.
Webinar moderator and Africa Area Manager at MORFO.
How important are mine site rehabilitation projects?
Before opening a mine site, it is essential to carry out a number of preliminary studies. Among these, the development of rehabilitation plans is a crucial step. These plans detail the measures to be taken during the mining project and after mine closure.
Emphasis on rehabilitation is essential to safeguard jobs, surrounding communities and future generations. Indeed, rehabilitation aims to restore areas affected by mining, reduce environmental impacts and create conditions conducive to life and sustainable development.
In this context, explains Mr. Ettien, GPMCI (Groupe de Promotion des Mines en Côte d'Ivoire) will be asked to develop specific tools to facilitate the rehabilitation of mining sites. These tools could include guidelines, innovative technology and effective methodologies to ensure the successful and responsible rehabilitation of mining areas.
When it comes to rehabilitating mining sites, are there any parameters that should be monitored as a priority?
It's crucial to integrate progressive mine rehabilitation from the earliest stages of a mining project, particularly during the research phase prior to construction. By thinking about rehabilitation from the outset, we can anticipate and prevent problems that may arise at the end of the operation.
Setting up a soil monitoring program is essential. For example, it is important to monitor soil erosion, as this can lead to the movement of chemicals to other areas, including water resources, which can affect surrounding communities.
Air quality is another crucial aspect to consider. If the risks associated with dry spells, fires, lung infections and tree damage are not anticipated, this can jeopardize the safety of mine workers and have a negative impact on the environment. It is therefore essential to put measures in place to minimize these risks.
By taking this approach, integrating rehabilitation from the earliest stages, implementing soil monitoring and anticipating air quality risks, it is possible to reduce rehabilitation costs over the long term, preserve the environment and pass on the benefits of mining to local communities.
What are the current challenges in mine site rehabilitation?
When a mine closes, it's essential to accompany the process of land reclamation to enable revegetation. Today, we are able to grow plants on trays using mainly topsoil (the nutrient-rich top layer of soil).
However, the main challenges lie on slopes, which are often steep. In these areas, we do not recommend the use of hydroseeding techniques due to their high cost and the lack of specialized companies nationwide to carry them out. It is therefore essential to concentrate our efforts on developing suitable solutions for these slopes.
What are the new technology for mine site rehabilitation in recent years?
Faced with the various environmental obstacles present in the region, it is important to promote innovations that transform these challenges into job opportunities. By implementing certain measures, it is possible to transform environmental obstacles into sustainable employment opportunities. Here are some key steps:
- Obstacle analysis: It is essential to observe and analyze in detail the specific environmental obstacles present on the site. A first step is to carry out a soil analysis to determine whether or not the soil is contaminated.
- Soil remediation: If the soil is not contaminated, remediation measures should be implemented to restore it to its original state. This may include techniques for depolluting the soil and restoring its fertility.
- Selecting the right species: Once the soil has been rehabilitated, it's important to determine which plant species can thrive successfully on this type of soil. This will enable us to select the most suitable plants for reforestation and subsequent agricultural projects.
- Working with local populations: Small-scale illegal mines can present particular challenges. It is therefore crucial to collaborate with local populations to find joint solutions. It can be beneficial to train gold miners in green trades, encouraging their integration into sustainable activities.
- Rehabilitation and agricultural projects: The aim is to restore the land to its original state before mining, by rehabilitating the soil, and then implementing agricultural projects benefiting landowners where the area was already forested. This preserves natural habitats while generating economic opportunities.
- Chemical management: It is essential to use plant species that are adapted to contaminated soils and can absorb these chemicals from the soil. This guarantees effective decontamination and rules out agricultural projects in these areas.
- Upgrading degraded soils : Before starting any project, it is essential to carry out an accurate assessment of the condition of degraded soils. This enables the soil to be developed in an appropriate and sustainable manner.
Rehabilitation of mining sites varies according to the type of site. For manganese mining sites, existing topsoil may be sufficient to encourage natural regrowth. For small gold mines, on the other hand, more intensive measures are often required, such as burying with clay and replacing with topsoil.
What tech innovations would miners like to see on their sites? How can these new technology rehabilitations be more effective?
The adoption of new technology methods for rehabilitating mining sites can increase the efficiency, speed and scope of rehabilitation work, while helping to preserve the environment and promote the growth of healthy ecosystems on these sites.
Here are just a few of the innovations we'd like to see on these mining sites:
- Improved monitoring techniques: It is essential to develop techniques to support the revegetation of mine sites, particularly in areas where natural growth is limited. This involves finding effective methods to prevent the proliferation of invasive species and encourage the regrowth of native species.
- Access to difficult areas: Mining sites can be located in areas that are difficult for humans to access. The use of technology such as drones or robots can make it possible to explore and work in rugged or dangerous terrain, facilitating the rehabilitation of inaccessible areas.
- Slope rehabilitation: Slopes are often difficult to rehabilitate due to their steep shape. The development of specific techniques to replant and stabilize these areas can be a valuable technological innovation to improve the efficiency of mine site rehabilitation.
- Modernizing planting times: At present, planting is often limited to the rainy season. Technological innovation could enable plants to be planted at any time of year, even outside the rainy season, using appropriate water management or irrigation methods.
- Soil enrichment: Using drones to spray areas with nutrients or beneficial substances could promote rapid plant growth and improve soil quality. This would speed up the rehabilitation of mine sites and maximize the surface area covered.
Close collaboration with small mines is also essential. Accompanying them from the outset, providing advice and training in health, safety and environment (HSE) matters, can improve understanding and control of these important aspects.
The importance of local populations in rehabilitating mining sites
Local populations play an essential role in the rehabilitation of mining sites, thanks to their knowledge of the territory and their relationship with the environment. Their active involvement makes it possible to monitor rehabilitation projects on a regular basis, share information on site conditions and identify specific needs and concerns. Moreover, as they are often the landowners, their cooperation is necessary to guarantee access to and use of the land concerned. In many cases, local legislation also encourages the use of local labour within a 5 km radius of the site. Close collaboration with local populations thus fosters a more inclusive, environmentally-friendly and socially sustainable approach to mine site rehabilitation.
An example of mine site revegetation
"During my first mining experience at a uranium mine, as Senior Technical Manager, I was responsible for overseeing mine rehabilitation work. A particularly sensitive aspect of this experience was tailings management. We opted to bury the tailings under several layers of clay, taking care not to plant trees on top (a technique recommended at the time). Instead, we revegetated, mainly using paspalum, a plant that did not disfigure the landscape. This approach provided work for the local workforce, mainly women, which was very gratifying and a source of pride.
However, in today's mining operations, where mechanization is widely used and work progresses rapidly, the question of rehabilitation is often neglected. As experts, our job is to recommend a number of solutions, taking care to use only local species." - Michel Oyo
But is it better to replant manually or let nature take its course? It's a crucial debate that's not yet over, because today it generally takes 5 to 10 years to see concrete results on revegetation projects, while nature can also regenerate on its own. A mixed approach can always be adopted.
How to make a sound financial assessment when rehabilitating a mine site?
To carry out an accurate financial assessment for rehabilitation, it is essential to consider several key factors, such as human resources, the use of machinery, seed collection and the establishment of nurseries. The costs of employing qualified staff, acquiring and maintaining machinery, collecting and preparing seeds, and managing waste and materials all need to be taken into account. In addition, it is important to include long-term monitoring and maintenance costs to ensure the sustainability of the rehabilitation. Rigorous financial evaluation requires accurate data, and can benefit from the expertise of rehabilitation specialists.
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