From Drain to Gain: Reinventing Water Use in Mining Industry

All human activity depends on the availability of water. From basic survival to the most complex and innovative industries, it is a resource whose quality and quantity affects the well-being of every person, business, and nation. However, water, especially of the quality needed for human society, is not unlimited. Which is where water management comes into play. And like all industries, the mining industry has the duty of using water in a responsible and sustainable way.

The Role of Algae in Water Management in the Mining Industry

Water is both critical to the profitability of the mining industry and used up and polluted in large quantities as part of this process when done unsustainably, harming local communities and habitats. This means that the mining industry has a triple imperative for more sustainable water management, driven by economic, environmental, and social needs. Water is essential in both surface mining and underground mines for processes such as dust suppression, mineral processing, and cooling of machinery. Additionally, the presence of harmful algae in polluted water can further degrade local water resources, posing health risks to both humans and wildlife.

The mining industry is a significant user of water resources, with many mining operations relying on large quantities of water for various purposes. Water is essential for processing and extracting minerals, cooling systems for equipment and machinery, dust suppression, and washing and cleaning of mining equipment and vehicles. This extensive water usage can have profound impacts on local water resources, including both surface and groundwater. Harmful algal blooms (HABs) can occur in these water bodies, leading to additional challenges in water management due to the toxins produced by these blooms.

Challenges Faced

Mining companies often face challenges related to water management, as their operations can lead to the depletion of local water resources and pollution of surface and groundwater. The environmental and social impacts of water usage in the mining industry are significant, affecting aquatic ecosystems, wildlife, and human health. Effective water management is crucial to mitigate these impacts and ensure the sustainability of mining operations.

A report published by CDP (The Carbon Development Project) in 2013 presented data collected from companies regarding their water usage and associated risks. It indicated that 64% of mining industry respondents had experienced negative water-related business consequences in the previous five years.

In recent reports by the CDP – Metals and Mining Report 2019 confirms that the risks remain, with industry respondents having suffered water-related financial losses amounting to $11.8 billion over the past five years. Understanding water needs and quality is essential to creating programs that balance the large water requirements of successful mining operations. The right approach to water management and treatment can help alleviate operating issues and keeps business impacts at bay while also maximizing mining operation efficiency.

What is water used for in the mining industry?

• Mineral processing uses water in industrial quantities for quarrying, milling of mined materials, injection of water for secondary oil recovery or for unconventional oil and gas recovery (such as hydraulic fracturing), and other associated operations. Several economically relevant materials require water for extraction, including coal, iron, sand, gravel, crude petroleum and natural gas. Moreover, water is needed for the cooling of machinery, for centrifugal separation and for chemical processing.
• Wet dust control systems require vast quantities of water. These systems use spray nozzles either to apply water at the dust source and prevent the dust from becoming airborne in the first place or to target the airborne dust particles to suppress and minimize the distance the dust travels. Whether during mineral processing, at waste dumps or on haul roads, dust control is vital for minimizing health and safety risks, as well as for lowering impact on the environment.
• Transportation is typically the biggest water demand of a mine. The ore is crushed and suspended in an aqueous slurry, which is then pumped through a pipeline to the processing plant. While using more water than conventional transportation methods such as trucks or trains, this method is a lot more energy efficient and economically viable.

Types of Water in Mining

• Raw water refers to water sourced from precipitation, groundwater, rivers, or lakes. It is primarily used to meet operational demands such as employee consumption, process make-up water, underground mine water requirements, mobile equipment washing, and fire suppression systems.
• Compliant flow describes non-contact water that has not interacted with mining or mineral processing activities. This water complies with environmental regulations and can be discharged directly into the environment without the need for treatment.
• Non-compliant flow, or contact water, has come into contact with mining processes, including mineral processing and tailings disposal. As a result, it is unsuitable for direct environmental discharge and typically requires treatment.

Underground mining operations, in particular, require substantial volumes of water for critical functions such as shaft cooling and dust suppression. To enhance water use efficiency, non-compliant flow is often collected, reused on-site to the greatest extent possible, and subsequently treated to meet regulatory standards.

To sum it up, without adequate amounts of clean water available, many minerals cannot be extracted to begin with. Access to water is then needed for the safe and efficient use of industrial machinery and to lower human health risks, and improves the profitability of deposits, especially remote ones that do not have access to roads or rail infrastructure.

Challenges to water management from harmful algal blooms

The challenges encountered while trying to supply water for a mining operation will depend on a regional basis. In dry climates like the southwestern United States, northern Chile, southern Peru, and northern Africa, the key issue is low water availability. The deficit must be met through efficient water management focused on water conservation and reuse.

For instance, in northern Chile’s Atacama Desert, mining activities have intensified tensions between economic development and environmental preservation due to substantial water consumption impacting local ecosystems and communities.

In wet regions like Colombia, Indonesia, and New Caledonia, the obstacles include flood events, which can result in spilling events, erosion, and infrastructure failure. Lastly, operations in cold climates like Canada, Russia, and Finland must consider the water resulting from snow melt and ice thaw due to mining activity, ensuring appropriate drainage is possible without impacting the environment or the extraction activity.

Mining activities can disrupt aquatic ecosystems, affecting microscopic organisms that play a crucial role in maintaining water quality. Unsustainable use can have adverse consequences on humans and the living world. Events such as the Baia Mare cyanide spill destroy ecosystems, create high costs due to environmental lawsuits, and lower public trust in mining. 100,000 tons of cyanide-contaminated water was released when a reservoir broke, releasing them into the local rivers Someş, Tisza, and Danube, wiping out up to 80% of the aquatic life within the affected regions and contaminating the drinking water of over 2.5 million people. This is why each individual mine must develop a holistic, integrated approach to water management.

Health Effects of Mining on Drinking Water

The mining industry can have significant impacts on drinking water quality, particularly in communities located near mining operations. The extraction and processing of minerals can release harmful pollutants and toxins into the environment, contaminating drinking water sources. Exposure to heavy metals and other toxic substances from mining activities can also lead to serious health issues, including an increased risk of cancer, neurological and developmental problems, and gastrointestinal and kidney issues.

Harmful algal blooms (HABs) are a major concern in mining-affected waters. These blooms occur when algae produce toxins that can harm humans and wildlife. Blue-green algae, in particular, can produce toxins that cause liver and kidney damage. The presence of harmful algae in drinking water sources can pose significant health risks to local communities. Ongoing research is exploring the long-term health impacts of these blooms and innovative approaches to manage them and their associated toxins.

How Can Mining Companies Improve Water Use Efficiency?

Mining companies are increasingly adopting methods to improve water use efficiency, driven by the need to reduce environmental impacts and comply with regulations. Monitoring and reporting water usage are also critical components of efficient water management.

Innovative technologies are playing a key role in enhancing water use efficiency. Water treatment plants can remove pollutants and toxins from wastewater, making it suitable for reuse. Forward-thinking mining companies are implementing systems that recycle and reuse water, along with technologies that reduce water usage in processing and extraction operations. These efforts not only conserve water but also reduce operational costs and environmental footprints.

Regulatory Frameworks and Community Engagement

Regulatory frameworks and community engagement are critical components of responsible water management in the mining industry. Governments and regulatory agencies hold mining companies accountable for their water usage and environmental impacts. Key regulatory frameworks include environmental impact assessments, water quality standards and regulations, as well as permitting and licensing requirements.

Community engagement is equally important, as local communities can be significantly impacted by mining operations. Mining companies should actively engage with local communities and stakeholders to address their concerns and needs. Transparent communication and collaboration can help build trust and ensure that mining activities are conducted in a socially responsible manner.

Why do mining industries need eco-friendly solutions?

Chemicals are not a sustainable solution for the mining industry as they will risk environmental compliance. Sustainable solutions are essential to reduce the environmental and social impacts of the mining industry’s water usage. In recent years, many companies are exploring sustainable water management practices, using renewable energy sources, and developing reclamation and rehabilitation plans. They actively engage with local communities to ensure responsible operations. By managing water sustainably, they also help mitigate the impact of harmful algae.

Some companies are adopting innovative solutions like algae-based systems to remove pollutants and toxins from wastewater. Using wetlands and green roofs are also alternatives that are being explored to reduce stormwater runoff and improve water quality. Others implement advanced technologies, including real-time water monitoring and sustainable algae treatment methods, to reuse existing water and boost efficiency. By adopting these practices, the mining industry reduces its environmental impact and supports the well-being of local communities.

Additional methods to use in water treatment plants

As pressure mounts to improve efficiency and reduce mining’s environmental impact, technologies need to be implemented to optimize water use. These approaches are limiting the volume of water used in operations. For example, utilizing lower-quality water sources like seawater and treating mining water for reuse.

Suitable methods are necessary to both ensure water availability and avoid excessive use of chemicals. This may risk breaking environmental compliance. One way to capture non-compliant flow for reuse and treatment is through tailing dams. However, the high pH and salinity frequently give rise to algal blooms. This can clog filters and make water reuse significantly slower and more expensive. Chemicals like copper sulphate disrupt waters natural chemical composition and does not have lasting effects. Although, it is an easier option for algal growth removal, it has severe environmental impacts. Additionally, chemicals are always compliant with regulations. Manual removal and cleaning are costly, labor-intensive, and time-consuming, slowing down extraction and lowering profits.

Sustainable solution for drinking water

Mining companies are deploying the MPC-Buoy, an innovative, environmentally friendly solution to control algal growth and improve water use. Understanding the different algal species and their specific growth conditions is crucial for developing effective and sustainable algal control methods. The ultrasound technology only targets algae growth, leaving other aquatic life unharmed and preventing algal toxins from being released. The system can prevent algal blooms by using real-time water quality monitoring. This allows for business as usual while conserving water and saving time and money.

Phytoremediation and Algae

Phytoremediation, the use of plants to remove pollutants from the environment, can be an effective method for mitigating the effects of algal blooms. Algae, particularly green algae, have been shown to be effective in removing heavy metals and other pollutants from water. This process involves the algae absorbing and accumulating contaminants, thereby cleaning the water. The mining industry, which often generates large amounts of wastewater, could potentially benefit from the use of algae for phytoremediation.

2 Cases:

• Vale’s Tailings Dam in Brazil
  Vale, the world’s largest iron ore producer, faced challenges with algal blooms in its Barragem Sul tailings dam. These blooms caused foul odors and led to water quality complaints from nearby residents. In response, on May 8, 2021, Vale deployed three MPC-Buoy units. Post-installation data indicated successful algae control, with chlorophyll and phycocyanin concentrations maintaining between 0-3 µg/L. Turbidity ranged from 1.39 to 17.62 FNU, with a mean of 3.7 FNU. Additionally, the water’s pH averaged 7.33, reflecting improved water quality.

• Masbate Gold Project in the Philippines
  Masbate Gold Project in the Philippines encountered significant operational challenges due to algal growth in their tailings dam. This clogged sand filters in the water treatment plant. This necessitated daily maintenance, escalating operational costs. To address this, in February 2021, PGPRC installed six MPC-Buoy systems. Within six months, chlorophyll-a levels dropped from a baseline of 200 mg/L to a stable 1.2 mg/L. This substantial reduction not only improved water quality but also decreased the frequency of filter cleaning. Hence, leading to more efficient operations and cost savings.

Conclusion

Water is essential to every part of the mining process, but using it responsibly is becoming more important than ever. From keeping operations running smoothly to protecting local communities and ecosystems, water management is needed. With growing environmental challenges and stricter regulations, mining companies have a real opportunity to make a positive impact. By turning to sustainable solutions like algae control and using nature-based methods. Sooner companies can cut costs, stay compliant, and support the environment all at once.