Tag Archives: desalination

United thinking on mining, water solutions can save money and protect the environment, Worley says

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Today, the need for extraction and refinement of copper and other transition materials is essential to world development, as we navigate a transition to more sustainable energy technologies, Saleem Varghese and Carola Sepulveda* write. But as its importance has grown, copper ore grades have decreased at a rate of approximately 25% over the last decade – increasing demand pressures on the commodity – meaning miners need to process more material to achieve the same output.

Today’s copper mines also need a lot of water. A 50,000 t/d ore copper mine will consume around 30,000 cu.m/d of fresh water. This isn’t a problem in some geographies, but it’s critical to the viability of operations in some of the most copper-rich regions on earth, such as the Americas.

Copper miners in the Americas are united by the need to secure their water supply, reduce water consumption and manage their environmental impacts. What can they do to overcome these interrelated challenges, while meeting their production targets?

Where are we now?

Mining and processing depend on vast amounts of water, and for South American miners this leads to complications. The copper mines of the Americas are frequently located in arid and mountainous regions where water is scarce. Indeed Chile, a leading copper mining nation, is currently enduring a ‘mega-drought’ of 13 years and counting. Here, water is a national security issue, leaving some rural communities reliant on tankers to supply fresh drinking water.

This importance is recognised by miners as well, with local community impact and water management being the industry’s top ESG risks, concerning 78% and 76% of respondents, respectively, according to research by EY.

Indeed, by 2040, all Chilean copper mines are expected to be in areas suffering from water stress. Likewise, water efficiency is increasingly becoming a serious problem, with the water-energy nexus shifting and water becoming more expensive. For water-intensive mining processes, lack of access and an increasing price per litre can be potentially difficult hurdles to overcome.

For modern copper miners, there is a historic separation between mining and water operations which must be reengineered to improve water access and use. As mines see their speed to market and output slowed due to water stress, there are three key challenges which, if solved, will help the industry as it extracts the materials to electrify the world. Only by managing water and mining operations together and bringing in collaborative expertise, can miners tackle the challenges before them and deliver at pace.

Understanding the three critical factors for mining success

Water management is the key ESG factor copper miners face today, and this manifests in three key issues: one historic, one present and one which poses a challenge now and will only get worse.

The first challenge is securing a reliable water supply.

The second challenge is reducing water consumption and increasing water efficiency, to ease pressure on water supply.

And the third challenge is minimising environmental risks.

Overall, water issues could affect the viability of mining projects in many regions around the world. Mining operations require significant amounts of water for processes including mineral extraction, ore processing, dust suppression and more. However, in many areas such as in Latin America water is becoming scarce due to drought, climate change and overuse.

Supplying modern mines

To supply mines and refining plants, mines have recently moved away from shared groundwater supplies to desalinated water. Desalination is more expensive but offers less impact on local communities and environment. Given that mines in the Americas are usually distant from the coast and at higher altitudes, desalination represents a difficult challenge for engineers to make feasible. Alternatively, to secure groundwater lifting licences, consumption needs to be effectively managed, and any water put back into the environment must be treated effectively.

Solving the supply challenge by altering water consumption

In effect, the first problem, supply, can be eased by tackling the second issue: water consumption. If supply is the historical issue, using water more efficiently to alter consumption is the issue of today. Whether it’s water use in particle flotation or lost in tailings slurries (for transportation and storage), making sure these processes are done as economically, efficiently and sustainably as possible is key. This is where new technologies and solutions come in.

An example of this is seen in the storage of tailings. Where water cost and procurement are not an issue in different locales and climates, the storage of tailings in a slurry form is common. In arid conditions where water resources are strained, the economic sense behind storage slurries evaporates. Slurries not only take water out of the operational system and into a closed storage system (which will need to be replaced), but it also allows the potential for water loss through evaporation and seepage.

Dry storage techniques – which have increased in scale in recent years – are the obvious solution with greater water reclamation from tailings and increased safety in storage. Moreover, high-altitude mines and liquid-based storage pose a potential risk to those downstream, making dry storage safer and more effective.

Copper tailings from an old mine that are deposited between rock berms that help contain the sediment

Another example of reducing consumption can be through greater efficiency when appraising the ores to be processed. This can be done with advanced ore sorting technologies such as those offered by NextOre, a cutting-edge technology able to provide real-time analysis of newly extracted ores. Rather than typical analysis methods which can detect mineral particles at or near the surface of ore, NextOre’s magnetic resonance technology can evaluate and sort much coarser ore with accuracy and speed. This allows miners to selectively remove the waste or lower grade material before it enters the processing plant – ultimately saving water, with only the best ore to be utilised.

A common misconception about water projects is that they are expensive and require significant resources to implement. While water projects can be costly, it is important to consider the long-term benefits that they bring, such as increased water availability, environmental impact mitigation, improved access to clean water for communities, and further growth for industry.

Saving water, and protecting the local environment

The third issue, which is increasing in importance by the day, is managing the risk of localised environmental issues, especially acid mine drainage that can contaminate the natural environment.

This is an issue that is only going to become harder to tackle as the ores we are required to mine become lower grade and the ability to avoid sulphur-forming ores is lost. In this respect, new technologies can help as more challenging ores are treated.

Overall, the challenges faced by the industry cannot be addressed by a single solution, or by siloed teams attacking from all angles. A unified, collaborative approach will be needed for the best results.

The design and implementation of a water management approach should be tailored to the specific mine site needs and context of the community and stakeholders involved. For projects to succeed in the future, they must integrate mining, water and environmental capability under one roof – from front-end studies to delivery, and operations through end-of-life. Miners will benefit from working with a collaborative partner to consider mining operations and water issues holistically, and how new mining technologies can operate synergistically to help tackle these water challenges.

Why internal and external collaboration is key for businesses

The mining industry will struggle to solve its water challenges alone. And it doesn’t need to. The complexity of modern mine operations – and need for diversified expertise – simply reflects the scale of the energy transition, and the need to continuously improve environmental outcomes to maintain the social licence to operate.

The answer is not straightforward and requires a deep understanding of operations, mining, water management and the surrounding community. Collaboration needs to be coordinated to develop and implement real solutions for the enduring issues facing miners.

If done right, copper mining will bring lasting value to communities through low-impact operations that share the benefits of water infrastructure and provide meaningful local economic contributions. This is the responsible way to ensure we deliver the copper our world desperately needs.

*Saleem Varghese is Copper Growth Lead at Worley, while Carola Sepulveda is Water for Mining Lead, Peru, at Worley

Antofagasta responds to environmental concerns with new Los Pelambres copper mine plan

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Antofagasta Minerals is preparing to submit an investment proposal for its Los Pelambres mine in Chile that could see it stop using water from the Choapa River and nearby wells, and to use mainly seawater from 2025.

In this way, MLP will be able to guarantee the availability of water for its operations and advance its studies into extending its operations beyond 2035, when its current environmental permits expire, it said.

The submission to the Environmental Impact Assessment System (SEIA) also considers Minera Los Pelambres (MLP), the operating entity, building a new concentrate transportation system with modern control systems, routed away from the most populated areas. This will allow maintenance to be carried out without interfering with the daily life of the surrounding communities.

The 60%-owned mine produced 363,400 t of copper in 2019, alongside 11,200 t of molybdenum and 59,700 oz of gold.

Iván Arriagada, CEO of Antofagasta Minerals, said: “We are going to invest in works that allow us to adapt our operation to the changes that have occurred in the Choapa province and the region over the last 20 years as a result of the prolonged drought caused by climate change and the increase in its population and productive activity.

“This is a key step in the future of Los Pelambres.”

Arriagada added: “We have a long-term strategic vision to extend the life of the operations while ensuring its continued coexistence with other productive activities in the province of Choapa. We are particularly interested in taking care of natural resources that are scarce today, such as water, and continuing to reduce our potential impact on the environment.”

This new stage of the company’s development, called Los Pelambres Futuro, also includes the contribution of the Los Pelambres Expansion project, which was 36% complete as at the end of June. A significant part of the work on the project was stopped as a result of COVID-19 and construction is now restarting in stages.

“We want to make minor adjustments to the design of the expansion project, which is already under construction, to facilitate the future expansion of the desalination plant,” Arriagada said. “In this way, there we will be less impact on the environment.”

It is estimated that the Operational Adaptation Investment (OAI) will be submitted to the SEIA in the first half of 2021. Its execution could begin in 2023, creating up to 2,000 jobs.

The OAI includes the expansion of the 400 litre/s desalination plant, currently being built in Punta Chungo, and the industrial quality desalinated water supply system, to 800 litres/s.

Mauricio Larraín, General Manager of MLP, said: “If our investment proposal is approved, in the coming years we could stop extracting water from the Choapa River and nearby wells, and more than 95% of the water used by Los Pelambres will either come from the sea or will be recirculated water.”

This plan could see MLP become the first mining company in the central zone of Chile to operate predominantly with seawater.

“The decision to use desalinated water is an idea that arose from dialogue with nearby communities and authorities and seemed to us to be the best way that we could contribute to easing the water scarcity challenges in this part of the country that affects us all,” Larraín said.

The company, which currently has environmental permits to extract water from the Choapa River until 2035, has worked for years with its neighbours and the authorities on the water management of the Choapa Valley. This work will continue in the future with the objective of promoting the sustainable use of the available water and strengthening the Rural Drinking Water systems for human consumption, the company said.

Lastly, the Environmental Impact Study will include some continuity and maintenance works for the tailings system. These works are already included in the Environmental Qualification Resolution (RCA) 38/2004 and consist of works on the north and south contour channels, repositioning pipes and other works.

Arriagada concluded: “This set of initiatives will require very significant investment in the province of Choapa over the next 10 years, close to $1 billion, and will also generate a significant number of jobs. It will also contribute towards helping the region and the country overcome the social and economic crisis generated by COVID-19 as soon as possible.”

Black & Veatch helps the water balance at Escondida

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With BHP recently celebrating the completion of the Escondida Water Supply Expansion (EWSE) project at its majority-owned Minera Escondida mine in Chile, the designer and engineer of record, Black & Veatch, has taken the time to review its work on the more than two year project.

The expansion increases the mine’s desalination capacity to the point where 100% of its needs can be self-supplied with desalinated water, according to the company, helping to protect local groundwater resources while ensuring a more sustainable, resilient and reliable water future.

Black & Veatch served as designer and engineer of record on not only the EWSE project, but also the original Escondida Water Supply (EWS) project, heralded as one of the largest, most complex desalination infrastructure projects in South America, it said.

“Completion of the EWSE project comes amid mining’s growing focus on sustainability and resilience,” it said. “Minera Escondida is in the Antofagasta region in northern Chile, one of the driest regions in the world and water is at a premium. With the Monturaqui Aquifer closing in late 2019, BHP, the mine’s majority owner and operator, realised the need to bolster desalination capabilities.”

The project builds upon Black & Veatch’s history of providing water production, water conveyance and desalination services to BHP. In 2013, the company was selected to lead the engineering design, procurement, field inspection and pre-commissioning for the marine and desalination elements of the EWS project, which was completed in 2017.

When it came time to expand the Escondida desalination facilities, BHP again turned to Black & Veatch, hiring the engineering company to serve as engineer of record for the water production, water conveyance and high-voltage components of the project; providing engineering, procurement, construction management services, pre-commissioning and commissioning services.

The EWSE project involved multiple components to increase desalinated water production capacity by 833 l/s while expanding water conveyance capacity by 1,438 l/s. The project began in June 2017 and was commissioned one week ahead of schedule, on December 25, 2019, according to Black & Veatch.

“The project was executed on a tight timeline, but Black & Veatch was well-positioned to deliver on this work, given our knowledge of the original EWS project and the client,” Jim Spenceley, Senior Vice President of Black & Veatch’s Mining business, said. “This knowledge allowed us to identify efficiencies, reducing the amount of time to construct and commission and allowing us to safely deliver EWSE ahead of schedule.”

The original EWS infrastructure was developed with expansion in mind, and Black & Veatch’s design allowed BHP to adopt an optimised solution that used the existing EWS footprint, helping to lower capital costs, it said. Replicating equipment used in the EWS project also helped standardise and simplify operations and maintenance, according to the company.

Iain Humphreys, Business Line Director and Head of the company’s regional office in Santiago, Chile, said: “Black & Veatch provided the in-depth knowledge and experience to undertake this strategic project on behalf of BHP and to successfully complete EWSE. Having worked on both projects really pays testament to the high skill level and deep experience of all our professionals.”

Between the two projects – the original EWS desalination plant and the EWSE – Black & Veatch worked more than 3 million worker-hours without a recordable safety incident, it said.

To complete the project safely, ahead of schedule and with the highest quality standards, Black & Veatch placed significant resources behind the project. A diverse international team contributed – the core team of local professionals located in Santiago was supported by Black & Veatch professionals from multiple US states, plus the UK, India, Chile, El Salvador, Cuba and Colombia. The project also had a 25% female participation rate, supporting BHP’s corporate goal of gender diversity.

BHP builds its ‘green’ copper credentials at Escondida, Spence

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BHP says new renewable energy contracts it has recently signed in Chile will reduce energy prices for its Escondida and Spence copper mines by around 20% and help displace up to 3 Mt/y of CO2 emissions from these operations.

These agreements not only benefit BHP’s business but generate strong environmental and social value, according to Daniel Malchuk, President Operations for BHP’s Minerals Americas business.

BHP operates and own 57.5% of the Escondida mine, a leading producer of copper concentrate and cathodes from a copper porphyry deposit, in the Atacama Desert in northern Chile. Spence, which is 100% owned by BHP, is also in northern Chile.

He said: “Population growth and higher living standards combined with greater electrification are expected to push up demand for copper. This means that copper in products such as electric cars and renewable energy infrastructure, which are vital to the world’s sustainable growth, must be produced to the highest environmental aspirations.”

The new energy contracts, along with BHP’s investment in desalinated water in Chile, demonstrate social value in action and help drive the wider agenda for sustainable green copper, according to Malchuk.

Social value is one strategic pillar the company embeds in all its decision-making and informs the way in which it provides resources and generates long-term, sustainable value. This was the subject of BHP Chief External Affairs Officer, Geoff Healy’s speech in London earlier this month.

Malchuk said the company has negotiated four new power contracts that will meet its energy requirements at Escondida and Spence from 100% renewable energy sources by the mid-2020s.

“When fully operational, these renewable supply arrangements will eliminate virtually all of Escondida and Spence Scope 2 emissions (emissions from purchased energy), effectively displacing up to 3 Mt of CO2 annually compared to the fossil fuel contracts they replace,” he said. “This is the equivalent to annual emissions from about 700,000 combustion engine cars and accounts for around 70% of BHP’s Minerals Americas total greenhouse gas emissions.”

These actions also support Chile’s wider “Energia 2025” power policy target for 20% of all Chilean energy to come from renewable sources by 2025.

Following a competitive tender process, Escondida and Spence agreed separate 15-year contracts for 3 TWh/y and 10-year contracts for 3 TWh/year with ENEL Generación Chile and Colbún respectively. The ENEL contracts will begin in August 2021 and the Colbún contracts in January 2022, BHP said, with power supplied from solar, wind and hydro sources.

Malchuk said: “These contracts are practical examples of our commitment to social value that are linked to a sound business case. We estimate the agreements will reduce energy prices at our Escondida and Spence copper mine operations by around 20%, provide our operations flexibility and security of supply, and strengthen our ability to deliver sustainable copper across our supply chain.”

On top of this, the company has confirmed that its Spence operations will begin using desalinated water as the main source of supply from mid-2020 upon completion of a 1,000 l/s capacity desalination plant. This was part of a plan the company outlined in 2017 to grow the Spence operation.

This is on top of the more than $4 billion, 2,500-l/s desalination plant the company built at Escondida.

Malchuk said: “Water is a precious commodity that is critical to our operations in Chile and to the communities where we operate in the Atacama Desert, one of the driest regions in the world. We recognise our operations have an impact on the environment given the immense amount of water they consume.”

He added: “Our Water Stewardship position statement, launched last month, outlines our vision for a water secure world by 2030. It sets out our actions to improve water management within our operations and contribute to more effective water governance beyond the mine gate.

“We strongly support the UN Sustainable Development Goals on access to clean and affordable water. That’s why we will set public targets and engage industry, communities and governments to improve governance, transparency and collaboration in water management.”

Energy Recovery’s PX Pressure Exchanger finds a desalination market in Chile

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Energy Recovery, a leader in pressure energy technology for industrial fluid flows, has won awards of C$2.7 million ($2.02 million) to supply its PX® Pressure Exchanger® technology for desalination projects in Chile’s mining industry.

The company said these desalination projects will be used specifically in the mining process and are expected to ship this quarter.

Energy Recovery will supply its PX-Q300 Pressure Exchangers for multiple facilities, which will produce up to 148,000 m³/d of water. The company estimates the devices will reduce the facilities’ power consumption for all projects by 12.7 MW, saving over 110 GWh/y of energy and avoiding more than 65,740 t/y of CO2 emissions.

Energy Recovery’s President and CEO Chris Gannon said 2018 was shaping up to be a potential record year for the company.

He said: “These recent awards in Chile confirm the efficacy and strength of the PX technology. We are excited about the growth opportunities for our Water business and the continued strength and activity level for desalination throughout 2018 and into 2019. Moving forward, we will continue to aggressively pursue tactical initiatives across the broader water industry.”

Rodney Clemente, Energy Recovery’s Vice President, Water, added: “Energy Recovery has had its eye fixed on Chile as a strategic market and accordingly has positioned our company to assist these facilities in maximising the overall profitability of their operations through an increased understanding of the critical mining-water nexus.

“Energy Recovery’s PX Pressure Exchanger technology has the lowest-life-cycle cost of any energy recovery device on the market today, and this industry-leading value proposition resonates well with both our customers and end-users in Chile.

“More specifically, our uptime advantage in mining applications is unmatched – vitally important when every day of downtime translates to millions of lost dollars for our customers. We are excited to add another critical project to our successful global reference list.”

Energy Recovery is an energy solutions provider to industrial fluid flow markets worldwide. Its solutions recycle and convert wasted pressure energy into a usable asset and preserve pumps that are subject to hostile processing environments.

The PX Pressure Exchanger captures hydraulic energy from the high-pressure reject stream of seawater and then transfers this energy to low-pressure feed water with up to 98% efficiency and no electrical power. The result is a drastic reduction in energy consumption over previous methods.

It has only one moving part, manufactured out of a corrosion-proof ceramic that’s three times more abrasion-resistant than steel, the company says.

“It provides unmatched durability, and its simplicity allows for scalability, quick start-up, and virtually no required maintenance. In fact, many of our PX devices have been in operation for as long as 13 years without interruption,” Energy Recovery said.

ENAPAC solar-powered desalination project clears environmental hurdle in Chile

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The Energias y Aguas del Pacifico (ENAPAC) solar powered desalination project in the Atacama Region of Chile has reached another milestone, with the local government signing off the all-important Environmental Impact Study (EIS).

TRENDS Industrial, which is developing the project, said the Environmental Evaluation Commission recommended approving the EIS.

The ENAPAC project consists of a seawater desalination project that will be supplied with its own source of photovoltaic energy, for the mining region of Atacama. With an estimated initial investment of $500 million, ENAPAC will become the largest desalination plant in Latin America. It will have a maximum capacity of 2.630 l/s, a projected 100 MW of installed photovoltaic power and a water reservoir with 600,000 m³ capacity.

“Thus, ENAPAC will be one of the most advanced projects in the world with a combination of reverse osmosis desalination and photovoltaic energy,” TRENDS said.

Rodrigo Silva, TRENDS Industrial’s CEO, said: “The project will generate opportunities for local employment and suppliers, and our vision is that many users can access a sustainable and clean source of water ceasing the use of continental waters and the basins of the region, which suffers from a severe water stress. The response from the industrial sector, especially mining projects, has been very positive and we’re advancing conversations with many companies. Certainly, we predict the EIS approval will accelerate those conversations and agreements.”

The environmental evaluation from Chilean authorities for ENAPAC took more than a year and is part of the list managed by the Office of Sustainable Projects Management of the Chilean Ministry of Econom, TRENDS said.

Back in June, TRENDS Industrial signed a Memorandum of Understanding with Almar Water Solutions to develop the ENAPAC project