11 minute read
Maximising Sustainable Impacts
Iliass Elfali, OCP Group, Morocco, outlines how to maximise the impact of sustainable mining programmes.
Mining is resource-intensive and can be environmentally challenging if not counteracted appropriately, so mining companies must (at a minimum) operate sustainably within a circular economy in order to protect the planet. To create truly lasting value, however, a company’s sustainability programme cannot be insular – it is by adopting a holistic view of operations and investing in the technology, systems, and knowledge required to solve global challenges that each country, community, individual, and organisation can benefit.
The phosphate rock mining industry can serve as a good example of how maximising the impact of sustainable mining programmes can reap rewards much further afield. As phosphorus is an essential element for the production of fertilizers, food supplements and food additives, both the health of the planet and global food security are at stake. That is why OCP Group, the responsible custodian of the world’s largest resources of phosphorus, according to the United States Geological Survey (USGS), has developed and implemented an industrial plan that places resource preservation at the centre of its operations and applies sustainable thinking to all its activities across the whole phosphorus value chain. OCP also undertakes activities which may seem superfluous, but which will amplify the positive impact of its existing actions. This includes investing in processes to enrich low-phosphorus-content deposits, as well as combating climate change through mine reclamation, simultaneously creating value for local communities through aff orestation.
This article explores in-depth illustrations of practices which phosphate rock mining companies – and the wider industry – could consider as ways to maximise the impact of their sustainable mining initiatives.
Recovery of low-phosphorus-content phosphate rock
Resource preservation is important across the whole mining industry for the longevity of non-renewable minerals in a time of increasing demand. Companies should therefore be looking for ways to sustainably grow their existing deposits, whilst minimising their impact on the environment. Despite the USGS estimating that the world has many centuries of phosphorus resources left at current production rates, and Morocco being blessed with significant resources of high-phosphorus-content phosphate rock, OCP has developed an adapted reverse flotation process to help the company maximise the recovery of low-phosphorus-content phosphate rock during the extraction phase.
Beneficiation is a three-step process involving washing, flotation, and decantation. The phosphate rock is first measured and separated, with rock measuring more than 2.5 mm sent to the waste rock deposit. In the second step, the washed and sized rock, measuring between 0.125 mm and 2.5 mm (considered to be the final product), is stored. Rock measuring less than 0.04 mm is sent to the decantation basin, and rock measuring between 0.04 mm and 0.125 mm is sent to the flotation units for further treatment. Here, it undergoes attrition, desliming, ore conditioning and finally OCP's streamlined reverse flotation process, whereby flotation reagents are added to a single conditioner, enabling the recovery of both the carbonates and silicates (the floated product) at the same time. The non-floated product consists of the concentrated phosphate rock, and the floated product is sent to the decantation plant to join the rock measuring less than 0.04 mm, where both are mixed with anionic flocculants to increase the rock density and accelerate the decantation process. Water is then recovered from the thickeners for reuse in the washing units, as well as the remaining water recovered from the settling zones of the fine flocculated particles.
OCP’s Youssoufia and Khouribga mines already benefit from beneficiation, and it is also being implemented at the Boucraa and Benguerir sites. As a result, 33% of Moroccan phosphate rock deposits considered to have very low phosphorus content have become economically viable and exploitable. As phosphorus provides a quarter of all the nutrients that plants need for their growth, and higher crop yields can also help prevent deforestation across the globe, this is vital for ongoing food security and the health of the planet for centuries to come.
Figure 1. The Beni Amir Washing Plant in Khouribga, part of the three-step beneficiation process to recover low-phosphorus-content phosphate rock.
Figure 2. An argan tree being planted at a rehabilitated mine in Khouribga to provide a new source of income and opportunity for the local community.
Mine reclamation and rehabilitation
Local communities impacted by the presence of mining activities should be able to benefit from the operations and lead meaningful economic lives. Creating employment opportunities and investing in education and training is one means of giving back, but there are additional ways to create value for local residents.
For example, OCP endeavours to leave mined areas more fertile than they were found, by recovering the soil through reclamation and aff orestation activities. With an objective of reclaiming two times what is extracted every year, and 4.5 million trees planted and over 5000 ha. of land rehabilitated to date, this process is leading to major economic and social benefits for the local communities.
At the beginning of OCP’s mining operations, the topsoil is removed, collected and stored, preserving its properties. Once mining operations are complete, OCP restores the topsoil and improves its quality by adding ameliorants before planting new tree species. One of the soil amendments tested is biochar – a charcoal rich in carbon, peat moss, compost and byproducts of OCP’s operations, such as phosphogypsum, which results from processing phosphate into phosphoric acid. As a result, the soil’s structure, water retention and microflora are all improved, and the amendments also provide stable carbon for the soil and prevent the leeching of nutrients.
Reclamation has been used at OCP’s Khouribga mine to plant argan trees, a rare species valued highly worldwide, providing a new source of income and opportunity for the local community. The aff orestation of arid and semi-arid former mining sites can also contribute to carbon capture in regions of the world that are not particularly fertile, by creating a carbon dioxide sink. It is not an easy process, which is why the company is investing in further developing its expertise in rehabilitating such marginal lands, identifying species which will be high-growth and high-value-add for the region, optimised irrigation techniques and ways to support orphan crops, which are those not sold internationally but vitally important for local diets.
Preserving water and sharing solutions
The mining industry is a major user of water and reducing total water consumption requires an overhaul of operations and research and development (R&D) to devise new and innovative solutions. Investing in research and collaborating to share successes can not only help companies to become more water eff icient, but also benefit communities across the world.
Water is a precious resource across the globe, but particularly so in Morocco as a country that faces increasing water challenges. Recognising this wider problem, OCP has committed to preserve water resources during its operations – where it currently consumes 33% of its water during the mining process – and to use alternative and non-conventional sources, such as urban treated wastewater and desalinated water. Currently, 30% of the group’s water needs are covered by non-conventional water. Equally, 80% of the water used in the phosphate enrichment process is recycled for use in its operations. OCP’s targets are to reduce total water consumption by 15% by 2024, and to supply 100% of its water needs from non-conventional sources by 2030.
One of OCP’s key developments is the slurry pipeline, which enables the company to bypass intermediary processing stages, such as dehydration of the phosphate rock at the mining operations and re-watering at processing sites. By transporting washed phosphate rock as pulp directly to the main processing platform, the pipeline saves up to 3 million m3/y of water at its full capacity. This is a very energy eff icient solution, which utilises the diff erence in elevation between the mining and processing sites.
When it comes to non-conventional alternatives, OCP is unique in the phosphate rock mining industry for using wastewater treatment with activated sludge technology to provide over 10 million m3/y of reusable water, primarily for industrial use. The wastewater undergoes three levels of treatment: Pretreatment, including screening – a process to remove oils and sand and primary sedimentation. Secondary treatment, which encourages bacteria to grow with a controlled supply of oxygen. Tertiary treatment, involving microfiltration to eliminate residual dirt and suspended solids, granular activated carbon filtration to remove organics and produce a high-quality effluent, and finally disinfection to kill bacteria, viruses and other potential pathogens, before the water is sent to OCP’s mines.
The treatment plants also use renewable energy, as the sludge generated by the treatment produces biogas when processed, the recovery of which covers over 30% of the treatment plants’ electrical and thermal energy requirements.
In addition, over 25 million m3/y of seawater is desalinated for the company’s industrial use through seawater reverse osmosis (SWRO) technology, which uses clean energy. Taking the constraints of seawater quality variation on the costal intake into account, the plant has been designed with an advanced pretreatment unit (which involves dissolved air flotation and ultrafiltration through membranes 0.03 microns thick), in order to ensure a high pretreated water quality and maximum availability. The water is then re-mineralised and distributed. As well as the on-site eff luent treatment, the brine generated by the plant is diluted into the pumped cooling water and then reused in the hub’s processing units.
Whilst this is all part of OCP’s Water Program, designed to help the group transform its processes, these solutions are transferrable. As a result, OCP participates in Morocco’s ministerial water committee responsible for defining the 2050 ‘National Water Plan’ and the Moroccan Coalition for Water (COALMA), a non-profit association and member of the World Water Council, which aims to strengthen the exchanges between the public and private sectors when it comes to the
Figure 3. The desalination plant at Jorf Lasfar, part of OCP’s Water Program to help the group become more water eff icient.
Figure 4. The Green Energy Park in Benguerir, developed jointly with IRESEN to help OCP achieve its ambitious clean energy goals.
management of water resources. OCP has also installed 35 000 m (linear) of water pipe in Fkih Bensaleh and at two treatment stations to provide 30 000 individuals in Morocco with water from OCP.
Carbon-free and effi cient energy use through R&D
Much like water consumption, the mining industry is a major user of energy, so meeting needs via clean energy and becoming carbon neutral are hugely important tasks. To truly go above and beyond, companies can also look for ways in which to invest in R&D, which will be positive for communities that may suff er from limited access to vital resources.
For example, OCP has set ambitious energy goals, committing to meet all its electricity needs through clean energy by 2028 via wind, solar and cogeneration production, and achieve carbon neutrality by 2040. This is a significant undertaking, distinctive in the phosphate rock mining industry, and one which OCP has been investing in heavily since 2013. Currently, three of OCP’s mines – Benguerir, Youssoufia, and Boucraa – are supplied with almost 100% wind energy, whilst the Khouribga mine is supplied with 37%. Overall, 89% of OCP’s needs are met by clean energy. Diversifying OCP’s energy mix is being led in parallel with a wider Energy Eff iciency Program, which also identifies optimisation opportunities that may provide benefits for communities around the world.
Morocco is fortunate to have sunshine, which is why OCP is currently investing in solar energy studies and pursuing solar power patents. In conjunction with the Institut de Recherche en Energie Solaire et Energies Nouvelles (IRESEN), and with the support of the Moroccan Ministry of Energy, Mines, Water and Environment, OCP established the Green Energy Park (GEP) to develop new green energy solutions. Currently, OCP and the GEP are collaborating on the study and installation of two solar desalination systems for brackish water at Boucraa, which could present an alternative solution to cope with water stress in landlocked regions that have brackish underground water. Sharing the results of this study could have much wider global implications with industrial, agricultural, and domestic applications. The group is also planning to intertwine energy eff iciency and mine rehabilitation eff orts by utilising former mined land for solar farms.
Actions for mining companies
OCP’s transition from a miner to a successful innovator with new models for fertilizers, solar power, water preservation, and more is a clear example of how a company’s commitment to maximising the positive impact of its activities can provide lasting value both for the organisation and to a wider extent. Whilst companies in the industry are looking at ways to implement sustainable activities to reduce their environmental footprint, they should also study the broader role they could play, whether that is through collaboration, sharing solutions, looking aft er local communities, or investing in vital R&D.