What Does Mine Waste Valorization Look Like for Mine Rock?

Reprocessing Mine Rock for Closure Value

Another pathway for the valorization of mine rock is reprocessing. In our experience, systematic reprocessing of mine rock stockpiles is still rare but is an active area of exploration in the industry.

In the United States of America, the U.S. Department of the Interior has released several orders related to valorization of mine waste, including Executive Order 14241, Immediate Measures to Increase American Mineral Production, and Secretary’s Order 3436, Unlocking Critical and Strategic Minerals from Mine Waste, Cutting Red Tape, and Restoring American Dominance in Strategic Mineral Production. As of September 2025, the U.S. Geological Survey has awarded nearly $3 million in cooperative agreements to state geological surveys to study critical minerals in the materials left over from mining at active and legacy sites (U.S. Geological Survey, 2025). At the Prospectors & Developers Association of Canada (PDAC) this year, we met some members of the North American Iron team, who are developing a pig iron production project that reclaims and processes Minnesota’s historic iron stockpiles (North American Iron, 2026).

A practice we see regularly in mine and closure planning is the low-grade ore stockpile. We have seen mine operations stockpile marginal ore material and call it “temporary,” with plans to process it at a later date. However, because it’s considered temporary, the stockpile may not be designed or constructed through a long-term or closure lens (such as being lined or constructed with source control measures in place). In some cases, operators may never process the material, and then these temporary stockpiles, which were previously considered an asset, become an environmental liability (Nkuna et al., 2022).

To quantify value, it is critical to understand the concentration of low-grade ore in the MRS and the volume of rock. Three-dimensional modelling tools (both spatial and geological) can help evaluate volumes, footprints, geometry, and ore grade when planning and designing stockpiles. Metallurgical testing is also needed to determine how the weathered low-grade ore will react in the processing plant and if any modifications are necessary. Combined with geochemical data, such as mineralogy and elemental composition, that describe the resource and the liability, these tools can give operators a clearer picture of whether reprocessing is feasible.

In some instances, even without reprocessing, mine rock can be valorized. Almost 10 years ago, Anaconda Mining Inc. and Shore Line Aggregates entered into an agreement to ship an aggregate product made from surplus stockpiled mine rock (Anaconda Mining Inc., 2016).

Exploring the potential value in mine rock is not an excuse to defer closure planning or design. An integrated mine closure plan must first provide for safe, stable closure, but operators should not ignore the potential for second-act value extraction. As operators explore opportunities to optimize fully integrated mine and closure plans, they could uncover value by reviewing legacy geologic records, conducting additional drilling, and asking what other value opportunities could exist.

Okane’s Approach

Regulatory and permitting obligations today often require a defined geochemical characterization program to manage and quantify risks. Geochemical characterization is already an integrated process of operations. Leveraging this data to evaluate the potential for stockpile valorization should be part of the process.

Okane has worked with clients to evaluate where mine rock valorization is practical, or could present an opportunity to offset closure costs, turning an otherwise liability into an asset.

At Okane, we align early MRS design choices, such as height, slopes, and bench configuration, with long-term landform objectives, working wherever possible to preserve future value. The challenge often lies in aligning near-term operational goals to optimize mine production and extract value, with the opportunity to manage and reduce long-term asset liability through thoughtful stockpiling and placement.

At one site we work with in Ontario, Canada, the mine operator had to remove potential cover system material to access ore and extract maximum value. We are working with the operator to effectively stockpile and directly place overburden materials to preserve their value, while progressively reclaiming the site’s MRS during operations. 

When we integrate geochemical understanding and early stakeholder engagement into integrated mine closure planning, we create the conditions for MRSs to hold value beyond closure. Whether through carbon mineralization, reprocessing for mineral recovery, or thoughtful landform design that enables post-mining land use benefits, the potential for valorization increases when it is integrated into the mine plan.

To explore how an integrated approach to mine rock valorization can support your mine and closure planning, contact our team at info@okaneconsultants.com.