This episode delivers a practitioner-level walkthrough of in situ copper recovery (ISCR), a technique that extracts copper from deep saline aquifers without moving a gram of rock. CEO Matt Uddenberg and Senior Process Engineer John Redwood explain the full technical stack: how you identify a suitable brine reservoir using repurposed oil-and-gas well logs, how you design the lixiviant chemistry to selectively dissolve copper while leaving iron and manganese in solution, and how you engineer the surface processing circuit—ion exchange followed by solvent extraction and electrowinning—to handle the unique challenges of high-salinity, high-temperature pregnant liquors.
The conversation gets into the granular details that matter to anyone evaluating the technology's viability. They discuss the permeability ranges required for economic flow rates, the geomechanical risk of formation plugging from secondary mineral precipitation, and the thermodynamic modeling they use to predict copper speciation in chloride-rich brines at depth. They also address the environmental arithmetic: a closed-loop wellfield with continuous reinjection means no dewatering of aquifers, no open pit, no tailings facility, and a surface footprint measured in acres rather than square miles.
On the development side, the episode covers the specific permitting pathway in Arizona, where existing aquifer protection regulations provide a framework that ISCR can slot into, and the capital requirements to move from a pilot-scale demonstration to a commercial wellfield producing cathode copper. The hosts are engineers talking to engineers—there is no marketing gloss, just a clear-eyed discussion of what has been proven at bench scale, what remains to be demonstrated in the field, and where the real technical and financial risks sit. Listeners will come away with a working understanding of how ISCR differs from both conventional mining and in situ uranium recovery, and why it might unlock copper resources that are currently invisible to the industry's reserve statements.
Key Insights
- In situ copper recovery (ISCR) uses a closed-loop wellfield to circulate a mildly acidic lixiviant through a copper-rich brine reservoir, dissolving copper in place and pumping the pregnant solution to surface for extraction—no pit, no waste rock, no tailings dam.
- The target reservoirs are deep saline aquifers (1,000–2,000 meters) where copper is already dissolved in natural brines at parts-per-million concentrations; the innovation is engineering the fluid chemistry to selectively mobilize that copper without destabilizing the formation.
- The process borrows heavily from in situ uranium mining but faces a harder selectivity problem because copper travels with iron and manganese; the team describes using ion-exchange resins and solvent extraction circuits tuned specifically for high-salinity, high-temperature brines.
- Environmental savings are quantified: zero dry tailings, a 90%+ reduction in surface footprint compared to conventional open-pit operations, and no permanent groundwater depletion because the system operates as a continuous reinjection loop.
- The resource base is massive but unevenly characterized—the team explains how they re-log old oil and gas wells using neutron activation spectroscopy to map copper grades in brines that were historically ignored or logged only for hydrocarbons.
- The near-term bottleneck is not technology but permitting and first-of-a-kind financing; they detail the specific regulatory pathway through Arizona's aquifer protection permit system and the capital stack required to move from bench-scale demonstration to commercial wellfield.
Who should listen: Process metallurgists, mining engineers, and resource investors evaluating the technical feasibility and scale-up economics of subsurface extraction methods for energy-transition metals.
Why This Matters
This is a case study in how the energy transition is forcing mining to adopt subsurface engineering techniques from the oil and gas industry—ISCR turns a copper deposit into a chemical manufacturing problem rather than a materials-handling one. For investors and operators tracking the physical bottlenecks of electrification, the episode makes clear that the copper supply gap will be closed not by discovery but by extraction technology that radically lowers the cutoff grade.
