Resolution Copper Completes Deepening and Rehabilitation of Historic No. 9 Shaft

SUPERIOR, Ariz., Nov. 5, 2025 /PRNewswire/ -- Resolution Copper has reached a major milestone with the completion of its multi-year, $200 million rehabilitation and deepening of the historic No. 9 Shaft, a critical step in paving the way for one of the nation's most important new sources of copper and critical minerals.

Originally constructed in 1971 by the Magma Copper Company in Oak Flat and operated as a production shaft until the mid-1990s, the refurbished and deepened shaft now extends to a final depth of 6,898 feet underground, nearly five Empire State Buildings tall, and measures 22 feet in diameter. The completed No. 9 Shaft is now the second deepest single lift mine shaft in the United States, behind only Resolution Copper's No. 10 Shaft at 6,943 feet.

Rehabilitated and deepened from 4,800 feet to over 6,800 feet, the No. 9 Shaft now connects to the No. 10 Shaft, serving as ventilation and access for future underground development. Together, the network of underground mine workings form the backbone of the project's next phase of underground development, creating the foundation for future copper production that will strengthen the U.S. supply of this critical mineral.

"Completing the No. 9 Shaft is a huge milestone and a testament to the dedication and expertise of our underground team and contracting partners," said Vicky Peacey, President and General Manager of Resolution Copper. "This achievement underscores what's possible when American miners, homegrown talent from local communities including the Superior, Miami, Globe, San Carlos Apache Tribe, Hayden, Kearny and Winkleman, come together to do the job safely. While ongoing litigation continues to stall development, we are ready to advance this important copper project, enabling thousands of high-paying jobs, billions in economic development for rural Arizona, and access to a domestic supply of copper essential to American security and modern infrastructure. The sooner the litigation delays stop, the sooner this project can move forward, and the sooner Arizona and the nation will benefit."

The recent shaft-sinking project also achieved two years without a single medical injury or lost-time incident, underscoring Resolution Copper's strong commitment to safety. Over the course of the work, crews drilled nearly 14, 500 feet, poured more than 560 cubic yards of concrete, and installed nearly 140 yards of shotcrete.

"This accomplishment reflects years of planning, discipline, and teamwork between our people and partners," said Rob Tobin, Operations and Maintenance Manager at Resolution Copper. "Achieving this safely for more than two years without a recordable injury shows the professionalism and dedication of everyone who worked underground to bring No. 9 back to life in a modern way."

Redpath USA, the project's lead contractor, managed sinking and construction, supported by Globe-based Oddonetto Construction underground concrete and surface batch plant operations and logistics.

"We are proud of the innovative solutions developed in partnership with Resolution Copper, and Oddonetto Construction and the flawless safety performance achieved along the way," said Eric Stoll, Project Manager at Redpath USA.

"Completion of the No. 9 Shaft shows what can be achieved when local companies and national partners work side by side with a shared commitment to safety and excellence," said Kim Oddonetto, President Oddonetto Construction "This project demonstrates that with the right training and opportunities, we can build a skilled underground workforce right here in our communities, one that will help power Arizona's future for generations to come."

About Resolution Copper

Resolution Copper is Arizona Copper. The Resolution Copper Project is operated by Resolution Copper Mining, a limited liability company owned 55 percent by Resolution Copper Company (a Rio Tinto PLC subsidiary) and 45 percent by BHP Copper Inc. (a BHP PLC subsidiary). Learn more at resolutioncopper.com.

About Redpath USA Corporation

Redpath USA Corporation is a full-service underground mining contractor. Our expertise includes lateral development, shaft sinking, mechanized raise work, underground construction, and raise boring. The company draws on a large network of multinational experts and over 60 years of service to the global mining industry.

About Oddonetto Construction Inc.

Oddonetto Construction, Inc. is a minority- and woman-majority-owned General Contractor proudly serving Arizona for over 40 years. Oddonetto Construction is dedicated to performing quality construction services with an uncompromising commitment to safety and excellence. Oddonetto Construction takes pride in delivering quality work driven by our dedicated team whose roots run deep in the Copper Triangle area.

SOURCE Resolution Copper