As the world’s demand for critical minerals grows-driven by clean energy, agriculture, and technology-so does the need for smarter, more sustainable ways to extract these minerals. One method gaining momentum is solution mining, a technique that’s quietly transforming how we access essential resources like uranium, potash and lithium.
What is solution mining?
Imagine extracting valuable minerals without traditional mining methods. That’s the promise of solution mining. Also known as in-situ recovery (ISR) or in-situ leaching (ISL), this method involves injecting a liquid, called a lixiviant, into the ground to dissolve minerals. The mineral-rich solution is then pumped to the surface and processed into usable products.
This approach is already responsible for over half of the world’s uranium production, around 40% of potash, and a growing share of lithium, especially as demand for electric vehicle batteries surges.
Benefits
Solution mining offers several advantages over traditional mining:
- Minimised environmental footprint: Eliminates the need for open pits and tailings piles, significantly reduces surface disturbance and limits the volume of waste rock handled.
- Faster development: Wells can be drilled and brought into production more quickly than building a conventional mine.
- Energy efficiency: Eliminates the need for crushing and grinding rock.
However, it’s not without challenges. The technique requires specific underground conditions, and there’s a risk of fluids migrating into surrounding groundwater if not carefully managed.
Saskatchewan: Leading solution mining innovation
Saskatchewan, Canada, is emerging as a global leader in solution mining innovation. The province is home to cutting-edge projects across all three major commodities: uranium, potash, and lithium, each showcasing how this method can be adapted to different geological settings.
For six decades, Wood has been on the frontlines advancing Canada’s mining potential. Wood’s Saskatoon office is a centre of excellence for potash and uranium. The office has worked on most potash and uranium properties in Saskatchewan and many around the world.
Uranium: Breaking new ground at Phoenix
Traditionally, uranium ISR has been limited to sandstone deposits with high permeability and natural containment layers. But Denison Mines’ Phoenix project in Saskatchewan is rewriting the rule book.
Phoenix is a super high-grade uranium deposit, up to 100 times richer than typical ISR sites. To make ISR work here, the industry is using a freeze wall to artificially contain the lixiviant and carefully designing wells to manage flow through less permeable rock.
This project is advancing toward becoming the world’s first ISR operation in an unconformity-type uranium deposit, proving that even complex geology can be tackled with the right innovations.
Potash: Deep caverns and hot water
Potash, a key ingredient in fertiliser, is mainly mined from deep underground using traditional shafts. But in Saskatchewan, companies like K+S Potash Canada are using solution mining to reach deeper deposits than conventional mines.
At the Bethune operation, hot water is injected into underground caverns to dissolve potash. The brine is then pumped to the surface, where potash is crystallised and processed. This method allows access to resources that would be too costly or risky to mine conventionally.
The cavern development process is carefully staged, from creating a sump at the base of the deposit through primary and secondary mining phases, ensuring maximum recovery while minimising waste.
Lithium: Tapping into deep brines
Lithium is the essence of modern batteries, and demand is skyrocketing. While much of today’s lithium comes from hard rock or salt flats, a new frontier is emerging using deep underground brines, often located in oil and gas-producing jurisdictions.
There are several companies in southern Saskatchewan exploring this potential. The lithium-bearing brine is pumped from deep formations and processed using Direct Lithium Extraction (DLE), a technology that selectively recovers lithium, without needing massive evaporation ponds as practiced elsewhere.
This approach is more water-efficient and potentially more scalable than conventional lithium recovery from salt flats.
The future of mining?
Solution mining isn’t a silver bullet, it doesn’t work everywhere, and it requires careful design and monitoring. But as the examples in Saskatchewan show, it’s a powerful tool when used in the right conditions.
By combining geological insight, engineering innovation, and environmental responsibility, solution mining is helping unlock resources that were once out of reach. And as demand for clean energy and sustainable agriculture grows, this quiet revolution beneath our feet may just be what powers the future.
Solution mining is competitive with conventional mining across several commodities, reducing environmental impact while expediting project timeline. Wood has learned from its engagement in innovative projects developed here in Saskatchewan, that broaden the possibilities of how solution mining can be applied around the world.