Turning Mine Waste into Clean Water — and Value.

Tersa Earth is tackling one of mining’s biggest liabilities with a revolutionary system that recovers metals and neutralizes toxic runoff.

The Opportunity

As the world shifts to an electrified economy, the demand for essential metals is soaring but mining operations face mounting challenges: declining ore quality, limited access to water, growing community resistance, and stricter environmental regulations. One of the most persistent threats is Acid Rock Drainage (ARD) — toxic, acidic runoff that can devastate ecosystems, contaminate water sources, and saddle companies with long-term environmental liabilities. Traditional treatments like lime neutralization are inefficient, carbon-intensive, and produce problematic sludge. A better solution is urgently needed — one that addresses the issue proactively and sustainably.

The Challenge

Tersa Earth developed TersaClean, a two-step treatment system that not only neutralizes ARD but recovers valuable metals in the process. The system integrates Microbial Fuel Cells (MFCs) and Microbially-Induced Carbonate Precipitation (MICP) in a modular, low-energy format. The system selectively recovers multiple precious metals simultaneously from the tailings ponds and captures the toxic metals as stable carbonates. This neutralizes the ARD in the process, making the treated effluent suitable for discharge. Lab tests have shown impressive results, including 95% copper recovery in the MFCs and 99.99% removal of metals like arsenic and cadmium by the MICP process. The process significantly reduces gypsum sludge formation and can treat water in as little as 5–7 hours. With the core technology validated at bench scale, the company now needs to scale and prove performance in the field, with complex ARD compositions and across a broader range of metals.

NPC’s Solution

The NPC Proof of Concept Program is supporting Tersa Earth as it prepares for field trials of the TersaClean system. This will enable the company to finalize its field unit design, optimize system performance, and demonstrate the ability to treat 1,000 to 3,000 litres per day, with future capacity scaling to 10,000 litres. It will also aim to reduce treatment times, expand the list of recoverable and removable metals, and validate high-purity recovery of gold and silver. Success in this stage is critical to establishing operational protocols, de-risking the technology for commercial deployment, and attracting follow-on investment. By showing performance in real-world mine environments, Tersa Earth will be well-positioned to help the mining industry shift from reactive waste management to proactive environmental stewardship, while turning liabilities into revenue.