Carbonaught: Turning Quarry Waste into Climate Solutions

Andrew Pedley (left) and James Lyons, PhD, two of the co-founders (along with Rhys Heffernan, PhD) of Carbonaught (Photo courtesy of Carbonaught)

Basalt is one of the most abundant volcanic rocks on Earth. Formed from molten lava, it’s commonly used in construction for roads and buildings. But during the mining process, much of the finest basalt dust ends up discarded, considered waste.

Andrew Pedley, James Lyons, PhD, and Rhys Heffernan, PhD, all former mining professionals, recognized this overlooked material as a powerful opportunity to fight climate change. They left their careers to launch Carbonaught, a startup built around a bold idea: turn mining waste into something farmers could use, while also delivering measurable carbon removal. When this fine basalt is crushed further and spread over farmland, it locks CO₂ into the soil, which in turn is enriched with vital nutrients. The result is a system that improves soil fertility, reduces synthetic fertilizer use, and stores CO₂ in the form of stable carbonate minerals.

Many of today’s climate startups focus on capturing carbon with complex machines. Carbonaught takes a nature-based approach rooted in enhanced rock weathering. Rock weathering occurs when rainwater absorbs CO₂ from the air, becomes weak carbonic acid, and slowly dissolves silicate rocks like basalt. Carbonaught accelerates this by crushing basalt into fine powder to increase its surface area so it reacts faster in soil. This process not only durably sequesters CO₂ underground, it also releases nutrients like calcium, magnesium, potassium, and phosphorus.

“We’re not just removing carbon. We’re rebuilding soil,” said Andrew Pedley, Carbonaught’s co-founder and CEO, during an interview with Green Queen. “It’s a win for the climate and for agriculture.”

To scale this model, Carbonaught is currently developing a digital platform that will connect quarry operators, farmers, and carbon credit buyers. The platform aims to offer GPS-based application tracking, carbon removal verification, and nutrient benefit reporting. Once launched, it will bring greater transparency and accountability to both the carbon claims and agricultural benefits – farmers can see what nutrients they’re getting, and carbon buyers can verify how much carbon is being sequestered and where. The system uses soil sampling, baseline CO₂ measurements, and satellite monitoring to validate each project. This level of traceability is helping build confidence in a space filled with unverified claims.

Carbonaught works directly with quarries to repurpose existing basalt byproducts from the mining industry, avoiding the environmental cost of sourcing new material. Once processed, this basalt is delivered to farms and applied as a soil amendment.

According to the company’s internal data and preliminary field results, a 25-tonne application of basalt can provide roughly 500 kilograms of phosphorus and potassium, and over 2,000 kilograms of calcium and magnesium. These additions reduce the need for synthetic fertilizers while improving soil structure and microbial activity.

Real-world trials are already in progress. In Australia and the United States, Carbonaught’s basalt is being tested on farms growing sugarcane, bananas, oranges, avocados, and macadamias. The Queensland, Australia government awarded Carbonaught a grant of A$74,800 to support these trials. They’ve also received early-stage backing from climate-focused investor Better Bite Ventures.

While Carbonaught is gaining momentum, other players are also already active in the enhanced rock weathering space. Startups like Lithos, UNDO, InPlanet, and Mati Cabon are expanding across different regions with similar approaches. Most are now focused on strengthening their Monitoring, Reporting, and Verification (MRV) systems to certify the net removal of carbon from the atmosphere. Tracking how long carbon stays in the soil is still evolving. According to experts, permanence depends on several factors including rock type, soil chemistry, and application method. Carbonaught is currently integrating mass-balance MRV techniques and isotopic tracing tools to improve its accuracy.

Recent research in the U.S. Corn Belt found that up to roughly 15 metric tons of CO₂ per hectare could be removed over four years using basalt-based amendments. These trials also noted better crop yields and healthier soils.

There are still some hurdles to overcome. Even though basalt dust costs as little as $10 to $30 per ton, applying it across diverse crops and terrains involves transportation, machinery, and farmer training.

Regulation is also becoming a factor. Countries that import food are beginning to demand cleaner farming practices, often with carbon accounting requirements. For producers in places like Australia, this means practices like ERW could become essential to maintain export access.

Practical, science-backed solutions like Carbonaught’s prove that corporations don’t need to wait for futuristic technologies to take climate action. Even discarded dust can become a powerful tool in the climate change mitigation toolbox. Sometimes, the tools and answers we need to help stabilize our food systems and meet climate targets are already lying within reach.

Sharan Dhillon is an MBA candidate with a focus on marketing and a knack for social media strategy, content creation, and brand engagement. He specializes in crafting impactful, community-driven content across Instagram, LinkedIn, and Facebook to drive growth and foster connections. His experience spans roles like Social Media Strategist at Florence Fang Community Farm, where he collaborated on building engagement strategies, enhancing brand presence and generating B2B leads. Beyond work, he enjoys getting his hands in the soil through gardening and farming – a natural extension, coming from a farming family!