TUCSON, ARIZONA (May 18, 2026) — A $10 million transaction recorded April 27, 2026, involving mineral interests near Mt. Lemmon / San Manuel, tied to the renewed advancement of the Oracle Ridge copper project northeast of Tucson, that straddles the ridge between Pima and Pinal Counties.
The seller was Marble Mountain Ventures LLC, c/o Oracle Ridge Holdings, and the buyer was Silver Mountain Mining LLC and Wedgetail Operations LLC of Tucson. The transaction closed shortly after Eagle Mountain Mining announced a joint venture with Japan-based Nittetsu Mining Co. for the Oracle Ridge copper project.
Oracle Ridge is a historic underground copper mine located northeast of Tucson, near San Manuel. Eagle Mountain describes the project as less than a two-hour drive from Tucson and about 50 minutes from San Manuel. The company says the mine was previously operational in the 1990s and produced a high-grade copper-silver-gold concentrate. Existing infrastructure on the site includes approximately 18 kilometers of underground development and mine buildings, although the historical processing plant has been removed.
Under the April 2026 joint venture, Nittetsu acquired an 80% interest in Oracle Ridge, while Eagle Mountain retained 20%. Nittetsu will operate the project going forward and has committed to spending $20 million to retain its 80% interest.
Nittetsu entered into an agreement with Eagle Mountain on April 20, 2026, to participate in the Oracle Ridge copper exploration venture in Arizona. The agreement calls for a total investment of $20 million over four years for environmental permitting, drilling, exploration, and feasibility work. Nittetsu will also hold 100% offtake rights for the project.
The project has broader significance at a time of renewed interest in domestic copper resources and critical mineral supply chains. Eagle Mountain reports Oracle Ridge has a mineral resource of 28 million tonnes at 1.35% copper, with silver and gold credits, representing approximately 380,000 tonnes of copper, 10 million ounces of silver, and 142,000 ounces of gold.
Nittetsu is a Japanese mining and resources company established in 1939 with operations in mineral resources, machinery, environmental engineering, real estate, and renewable energy. Eagle Mountain said Nittetsu’s metallic minerals division operates a copper mine and advanced projects in Chile and is a joint venture partner in Hibi Kyodo Smelting Co., Ltd.
The local recorded transaction involving Marble Mountain Ventures, Silver Mountain Mining, and Wedgetail Operations appears to be part of the larger Oracle Ridge project consolidation and joint venture structure, rather than a conventional commercial land sale. While not a conventional real estate sale, the recorded $10 million mineral rights acquisition is significant locally because it ties the Oracle Ridge asset to a broader international mining investment and renewed interest in Southern Arizona’s copper resources.
The transaction underscores Southern Arizona’s long-standing role in the mining economy and the renewed importance of copper to domestic supply chains, electrification, infrastructure, and advanced manufacturing. Projects such as Oracle Ridge draw attention to the region’s mineral resources, technical workforce, and mining expertise, while also highlighting the opportunity to responsibly redevelop existing or historic mine assets rather than pursue entirely new greenfield development.
Kitco’s New York spot prices showed gold at $4,651.40/oz and silver at $83.39/oz. Daily Metal Price listed gold at $4,677.94/oz, silver at $84.78/oz, and copper at $6.56/lb for May 14. Trading Economics showed copper around $6.53/lb, down on the day but still sharply higher year over year. Gold Spot Prices | Silver Prices | Platinum & Palladium | KITCO