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Rethinking wastewater in mining

Deep Tech

Rethinking wastewater in mining

Words Jack Kennedy

November 7th 2024 / 8 min read

When you picture a mine, you might think of massive excavators, heavy machinery, and deep pits. Yet, there's another critical element that's less visible yet absolutely essential: water. And lots of it—mining just 1 tonne of gold uses over 250M litres of water.

Water is crucial across the mining industry, from processing ore and separating minerals to dust control and equipment cooling. Unlike urban water systems, mining companies must also manage their own water—from ensuring safe excavation below the water table to handling water usage in mine tailings. 

This creates three key challenges: securing a sustainable supply upstream, managing water safely midstream, and treating water downstream.

Zooming out further, climate change is intensifying water scarcity, while regulatory standards like the EPA in the US and the EU's Water Framework Directive are becoming stricter. Despite advances in many areas of mining, water technology has been largely stagnant for decades. However, many mining companies are recognising the need for a lifecycle approach to water and waste management—aiming to reduce water withdrawal and ensure that treated water is safely returned to the environment.

Here, we break down the key opportunities for innovation in water and wastewater treatment in mining, and what we’re looking for in startups tackling these challenges.

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Opportunities 

There are a number of startups focused on the measurement and reporting parts of the value chain. They are offering sensors, IoT devices, and data platforms that enhance our ability to measure what’s happening in real-time. Solutions like Ketos and Waterplan have created strong offerings to monitor and report on water usage. 

From our perspective, these parts of the value chain are now well-served, making it harder for new founders to enter and compete effectively.

However, three areas stand out as areas for innovation in mining: management, treatment and extraction.

Management

Mining operations face increasingly complex water management challenges. Large mines often excavate past the water table, where managing the risks of flooding and release becomes harder. The waste generated from this process is added to mine tailings, where water usage is vital and the risks are substantial in terms of managing these pits safely, particularly in response to changing weather patterns. 

Traditional approaches to water management rely heavily on manual monitoring and reactive responses. This creates opportunities for solutions that can predict, prevent, and actively manage water-related risks.

Ideas we’re looking for: 

  • Hydrogeological mapping and prediction: Models that predict water flows to help forecast how different barriers or dewatering strategies will impact local aquifers.

  • Dewatering technology: Automated solutions for proactive dewatering of mining sites, including advanced drilling, pumping, and control systems to manage water effectively.

  • Tailings management: Technologies that enhance the safety and adaptability of tailings storage, particularly systems that respond to environmental changes in real time.

  • Water in steel: Technologies that reduce water use in iron ore processing and steel production, such as more efficient ore washing techniques, closed-loop water recycling systems, and alternative cooling methods.

Treatment 

Looking beyond the mining industry, today's treatment processes are slow and energy-intensive, involving aeration, filtration, and chemical treatments that often create new waste streams. The energy demands are staggering: around 0.5 kW is needed per cubic metre treated. Multiply that across billions of cubic metres each year, and you can see why new solutions are needed.  

Mining presents a similar set of challenges when it comes to water treatment. The water used in mining often contains high levels of fouling agents, heavy metals, and chemicals, making treatment even more complex and energy-draining. 

Some startups are making progress. ZwitterCo's fouling-resistant membranes and Puraffinity's selective PFAS removal show real promise. Other solutions still address only one part of the problem, which means mining companies need to integrate with multiple suppliers working in sequence. 

Ideas we’re looking for: 

  • Full stack solutions: The "holy grail" is an all-in-one system—energy-efficient, highly selective (parts per billion), and flexible enough to treat multiple types of waste streams in the mining sector. 

  • Self-repairing infrastructure: Automated systems such as robotics or hydrophobic coatings designed to repair pipes and infrastructure at scale, reducing maintenance costs and downtime.

Extraction 

We can take the treatment phase one step further by tapping into the potential of extraction.

Wastewater often contains valuable metals (like copper, zinc, and nickel) and nutrients (like phosphorus and nitrogen) that can be recovered. This process, known as valorisation, not only treats the water but also offers a way to recycle some of the most critical metals and nutrients that power our economies. 

By converting waste into wealth, this approach can significantly reduce the demand for newly mined materials, create financial incentives for better wastewater management, and establish a virtuous cycle that supports continuous improvements in water treatment over time.

Startups like Allonnia and Sunchem are already using leaching solutions and/or highly-tuned nanofilters to capture valuable elements from wastewater. We’re looking for more solutions here, particularly those focusing on hard-to-extract elements, or providing an all-in-one solution that is less energy-intensive but still highly effective.

Ideas we’re looking for: 

  • Zero liquid discharge: Systems that completely eliminate wastewater discharge, while recovering valuable minerals.

  • Biological systems: Engineered microorganisms that can treat water and recover metals simultaneously.

  • Ocean desalination and metal recovery: Using geothermal or low-cost energy to desalinate ocean water while extracting valuable minerals.

Challenges

While these opportunities are exciting, building a startup in the mining sector comes with its own unique set of obstacles. Here are some of the key barriers and challenges to be aware of:

Energy vs efficiency trade-off: Highly selective treatment often requires more energy. With energy making up 20-30% of mining operating costs, balancing gains in efficiency with energy demands is key for commercial viability.

Legacy infrastructure: Mining operations often have substantial investment in existing water systems. Solutions must either integrate seamlessly or demonstrate a clear 10x improvement in effectiveness.

Zero tolerance for failure: Water system failures can bring entire mining operations to a halt. Startups need to prioritise reliability and be prepared for rigorous testing.

Waste lifecycle: Effective separation processes yield clean water and concentrated waste. Solutions must manage both streams, ensuring regulatory compliance and minimising disposal costs.

Remote deployment: Mines are often in remote locations with limited infrastructure and personnel. Startups must consider the logistical challenges, transportation costs, and the need for minimal on-site expertise.

Fouling: Mining water often leads to heavy fouling in treatment systems. Startups need to focus on preventing fouling or making maintenance more efficient.

Mining needs water, and as the pressures on our natural resources grow, there are countless opportunities to innovate and do things better. If you’re a founder tackling these problems, we'd love to hear from you. Reach out to Jack (jack.kennedy@foundersfactory.co) or apply directly here. 

Apply here

About Jack

Jack Kennedy is an Investor at Founders Factory, focused on climate and deep tech. He leads investments for our Mining Tech program with Rio Tinto. He brings prior experience both founding and investing in climate tech.

Words by
Jack Kennedy
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