The Robbin Crossover XRE Tunnel Boring Machine Ivanhoe Electric is to acquire for its Santa Cruz Copper Project will undergo a comprehensive overhaul and technical upgrade as part of the US$64.7 million purchase price.
The overhaul will include the full refurbishment of the TBM's 9.3m diameter cutterhead, along with the addition of new solutions designed for the site's geological conditions, before arrival and assembly at the Arizona site in early 2027.
Prior to the sales Robbins repurchased the TBM from Anglo American. It was deployed at the Grosvenor coal mine in Queensland, Australia, where it completed two underground declines totalling 1.8km over1000 operating hours.
Commenting at the purchase announcement, Ivanhoe Electric's executive chair Robert Friedland (pictured), said: "Robbins is an American company that pioneered the modern TBM and remains at the forefront of tunnelling innovation. TBMs have been deployed globally for more than half a century in mining and countless civil engineering projects."
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Ivanhoe Electric will use the Robbins TBM and material handling system for access development at the Santa Cruz Copper Project, but is also expected to deploy the machine to the nearby Texaco Deposit.
Friedland said the TBM "gives our engineers the ability to pursue a future phased expansion of the project, including the high-grade Texaco Deposit, a mere two kilometers away."
The Robbins Crossover XRE TBM is purpose built to operate in variable ground conditions encountered in underground infrastructure development. Capable of moving through hard rock, wet, and mixed-face ground within a single drive, it is particularly suited to the mixed ground conditions present through the decline development phase at Santa Cruz.
With earth pressure balance capability, the cutterhead chamber is pressurised against prevailing groundwater, directly controlling face stability and mitigating inflow through water-bearing zones and aquifer intersections.
A bi-directional cutterhead is used for excavation in soft soils, mixed-face and hard rock geology, while a high-torque/high-speed cutterhead drive system delivers the needed power to pass through challenging geology and structures.
During decline development, the TBM system installs a continuous, fully supported and sealed segmental steel-reinforced concrete lining, preserving geotechnical integrity, enhancing long-term safety, and producing a permanent, flat-bottomed decline structure suitable for life-of-mine design. The integrated process also includes the construction of a permanent conveyor system for material handling during development and ore handling during production.
When delivered to the site in Q1 2027, the TBM is expected to take 12 months to excavate a 4km-long single decline and negate the need for a Class V Underground Injection Control ("UIC") permit for silica gel grouting. Underground mine development is scheduled to start in Q3 2028, with first oxide copper ore placed on the heap leach pads expected in the Q4.
