Hudbay and Mitsubishi approve $2.07bn Copper World mine in Arizona

Capital cost rises 59% to $2.07 billion

The final investment decision follows a definitive feasibility study. Hudbay owns 70% of Copper World and Mitsubishi 30% under a joint venture agreement signed in January 2026. Initial growth capital of about $2.07 billion covers the 36 months before commercial production, or about $1.84 billion after accounting for the precious metals stream deposit. The total is 59% above the $1.3 billion estimate in the 2023 prefeasibility study. Hudbay attributes about $200 million of the initial growth capital to project scope changes since that study, including an optimized path to the year-five concentrator expansion.

Hudbay's own share is smaller than the headline suggests. It expects to contribute about $500 million, less than one-quarter of the $2.07 billion, with the first installment deferred until 2028. Chief financial officer Eugene Lei said the funding plan requires Hudbay to fund one-quarter of the project capital cost.

The funding plan combines several sources. Mitsubishi's $600 million initial joint venture equity investment comprises $420 million for its 30% stake and $180 million toward future development costs, approved in August 2025 and completed in January 2026. Wheaton Precious Metals is depositing $230 million, and about $650 million is expected from project-level debt, leaving leverage below 30%. The balance comes from pro-rata equity contributions by Hudbay and Mitsubishi, deferred to 2028. Mitsubishi's total investment is expected to reach $1.02 billion, including a $423 million additional equity contribution approved with the decision.

A second phase of spending sits outside the $2.07 billion and is meant to be paid from operating cash flow. It covers a $25 million molybdenum plant in year one, a $242 million in-pit crushing and conveying system planned for year three to cut hauling and rehandling costs from year four, and a $443 million concentrator expansion in year four.

National Bank Financial analyst Don DeMarco wrote in a note that funding "is not expected to be an issue", citing Hudbay's $915 million cash balance and free cash flow from its other mines.

RBC Capital Markets analyst Sam Crittenden wrote that the sanction was a positive step for Hudbay's medium-term growth plans, though the share price reaction may be limited because the scope and initial capex were largely as expected. Jefferies analyst Fahad Tariq said the expectation had been "significant capex inflation" and that Copper World is "highly leveraged to copper prices". Hudbay shares rose 0.2% to C$33.34 in Toronto on Wednesday morning, valuing the company at about C$14.8 billion.

Domestic supply and Hudbay's output

Hudbay says Copper World is designed to deliver finished copper directly to US customers. ConstructConnect associate economist Devin Bell noted that the concentrate it produces will still need smelting and refining, and that US output at that stage is well below its 1990s highs. The producer price index for copper and copper products was up 43.4% year on year, according to Bureau of Labor Statistics figures Bell cited.

For Hudbay, the project is expected to lift consolidated annual copper production to about 250,000 tonnes, roughly double current levels.

Copper World sits about 50 kilometres southeast of Tucson. Hudbay recast the former Rosemont Copper project in a 2022 preliminary economic assessment as a phased development, starting on private land with an option to expand onto federal ground later.

Hudbay estimates Copper World could generate more than $1.1 billion in total US taxes over the 15-year base case, rising to about $3.7 billion under the 37-year extension.

The economics Hudbay is underwriting

At a long-term copper price of $5.00 per pound, the base case carries an after-tax net present value of $1.2 billion and an internal rate of return of 17%. At $6.00 per pound the NPV rises to $2.3 billion and the IRR to 22%. Average cash costs are estimated at $1.65 per pound over the first 10 years.

The base case is a 15-year mine life on proven and probable reserves of about 390 million tonnes grading 0.47% copper. Measured and indicated resources add up to 1.2 billion tonnes grading 0.40% copper, for 4.99 million tonnes of contained metal.

Output averages 102,000 tonnes of copper a year over the first 10 years, an 11% increase on the 92,000 tonnes projected in the 2023 prefeasibility study. A concentrator expansion from 60,000 to 90,000 tons per day in year five lifts that to about 120,000 tonnes in years six to 10, Hudbay says, 43% above the 84,000-tonne average of the first five years. The expansion capital is expected to be fully funded by cash flow from the operation.

The base case assumes a payback period of 5.4 years.

Private land first, federal land later

The 15-year base plan sits inside Copper World's private land boundary and needs only state and local approvals. Hudbay says it has obtained all major permits needed to build and initially operate the base project.

The federal question comes later. An extension case would move mining onto adjacent federal land in year 10, subject to federal permits.

That scenario stretches mine life to 37 years and holds annual copper production at 117,000 tonnes from years 11 to 20, against the 102,000-tonne average of the base case's first decade. It carries an after-tax NPV of $2.5 billion and an IRR of 19% at $5.00 per pound, rising to $4.0 billion and 24% at $6.00. The extension case uses only measured and indicated resources and incorporates an optimized version of the second phase from the 2022 preliminary economic assessment. Hudbay also plans to convert about one-third of the project's tailings to filtered tailings from year five, which the company says would allow the concentrator expansion without an additional water supply.

What happens next

Construction runs 36 months, with first production targeted for the second half of 2029. Hudbay expects more than 1,000 construction workers and about 500 permanent operating positions once the mine is running.

The company will file a National Instrument 43-101 technical report containing the definitive feasibility study results.

The Copper World project was included in a Japan-US critical minerals cooperation framework announced in March.