Post: Unlocking Hidden Value: How Above-Ground Tailings and Heap Leach Pads Are Transforming the Future of Gold Recovery

Across North America and around the world, decades of gold production have left behind vast volumes of above-ground mineral material — primarily tailings impoundments and historic heap leach pads — that contain measurable quantities of residual gold. Traditionally viewed as waste, these materials are increasingly being reconsidered as strategic resources in the era of resource optimization, ESG accountability, and rising gold prices.

With gold trading above US$4,000 per ounce and advancements in non-cyanide processing chemistry, what was once considered an environmental liability is rapidly becoming a significant untapped asset class. At the forefront of this shift is RZOLV™, a breakthrough hydrometallurgical platform that is redefining how operators and investors approach above-ground material reprocessing.

The Scale of the Opportunity

Modern gold mining produces large volumes of tailings annually. Industry estimates place global tailings generation at roughly 13 billion tonnes per year, with gold accounting for an estimated 20–22% of that total. This translates to approximately 2–3 billion tonnes of gold tailings produced annually, and billions of tonnes already stored above ground in facilities, stockpiles, and heap leach pads.

In North America alone — encompassing the United States, Canada, and Mexico — decades of continuous gold production have resulted in an estimated 8–16 billion tonnes of stored gold tailings, plus large inventories of legacy heap leach pads.

Many of these materials contain economically relevant gold grades well below what would be required for conventional mining, but well within reach for strategically deployed reprocessing technologies. At current gold prices, even recovered grades of 0.35–0.50 g/t can yield strong in-situ value, especially when paired with low-cost, scalable chemistry.

Challenges with Legacy Materials

While tailings and heap leach pads represent an economic opportunity, they also bring technical and environmental challenges that have historically limited reprocessing:

• Residual reagents and complex mineralogy can depress recovery and increase water-treatment costs.

• Cyanide sensitivity and regulatory constraints in many jurisdictions restrict the use of traditional cyanide leach chemistry.

• High surface area and fines content in tailings can make oxygen delivery and reagent effectiveness uneven in the slurry.

• Water management obligations for legacy pads raise the stake for any reprocessing initiative.

These factors have narrowed the number of tailings and pads that are viable under conventional approaches — until now.

RZOLV™: A New Pathway for Resource Conversion

RZOLV™ is a non-cyanide, water-based formula optimized for above-ground materials. Its operating profile is fundamentally different from legacy and alternative chemistries:

• Mild operating conditions: pH ~2, controlled oxidation–reduction potential (ORP 150–200 mV), no elevated pressure or temperature required.

• Low reagent concentrations: ~5 g/L thiourea with electrochemical oxidation, resulting in stable, dilute solutions that are safe to handle and store.

• Process simplicity: Operable in open-air environments using standard mining infrastructure, without the need for specialized pressure vessels or exotic materials of construction.

• High selectivity: Designed to preferentially dissolve gold without aggressively attacking base metals and gangue minerals, significantly reducing parasitic dissolution and impurity load.

• Standard recovery: The gold complex produced is readily amenable to conventional activated carbon recovery, enabling carbon-in-leach or carbon-in-pulp workflows that are well understood in industry.

These attributes make RZOLV™ especially well-suited to reprocessing legacy tailings and heap leach pads, where high reagent intensity, instability, and corrosion concerns have historically deterred non-cyanide alternatives.

Rethinking Economic Thresholds

One of the major outcomes of recent advances in process chemistry is the redefinition of economic cutoffs for above-ground material. Under traditional primary mining scenarios, cutoff grades are often several grams per tonne. But when the material is already mined, ground, and above ground, the calculus shifts. At US$4,000/oz gold, even residual head grades of 0.35–0.50 g/t have compelling in-situ values:

Grade (g/t)	Gross Metal Value (US$/t)
0.35	~$45
0.50	~$64
1.00	~$129

When paired with low reagent costs, closed-loop reagent and water management, and incremental operating costs that are often lower than primary mining, these materials can deliver project-level returns that justify investment, permitting, and deployment.

Real-World Compilations Confirm Viable Inventory

A compilation of publicly available data reveals millions of tonnes of above-ground gold-bearing material in North America alone at grades ≥0.35 g/t Au, including both tailings and historic heap/leach pads. This represents only a minimum disclosed inventory — the real total is likely larger once non-disclosed and internal resource estimates are included.

Crucially, these materials are already crushed, often already permitted for disturbance, and typically located within or near existing infrastructure, reducing the friction associated with new mining projects.

Beyond Economics: ESG and Closure Alignment

Reprocessing tailings and heap leach pads isn’t just an economic play — it’s increasingly an ESG imperative:

• Reduces long-term water treatment loads and dam storage risk

• Minimizes future land liability and reclamation costs

• Demonstrates resource efficiency in line with circular economy principles

• Reduces cyanide usage footprint when alternative chemistries are viable

Regulators, insurers, and financiers are now more open to projects that reduce legacy risk, particularly when paired with robust environmental planning and measurable outcomes.

Conclusion: From Waste to Working Capital

Above-ground gold mineral inventories — once considered waste — are now at the center of a major resource conversion opportunity. With advancements in selective, stable, and low-toxicity leaching chemistry like RZOLV™, operators can unlock value that was previously uneconomic or inaccessible.

This is not about marginal ounces — it’s about rethinking the asset base of the gold industry, integrating legacy inventories into modern operations, and building a bridge to more sustainable, economically resilient gold production.

---

 Disclosure and Cautionary Statement

This article has been published by RZOLV Technologies Inc. as part of its corporate communications and investor relations activities and reflects the views and opinions of management as of the date of publication. It is provided for general informational purposes only and does not constitute investment advice, an offer to sell, or a solicitation to buy securities. Certain statements in this article may constitute forward-looking information within the meaning of applicable Canadian securities laws and are subject to risks, uncertainties, and assumptions that could cause actual results to differ materially. Readers should not place undue reliance on such statements. The Company’s officers, directors, and insiders may hold securities of RZOLV and therefore have a financial interest in the Company’s performance. Readers are encouraged to review RZOLV’s public disclosure documents available on SEDAR+ for a discussion of material risks and assumptions. Neither the TSX Venture Exchange nor its Regulation Services Provider has reviewed or approved the contents of this article.