Deepsea mining hopeful TMC – the metals company – has released two technical economic assessments for its polymetallic nodule projects in the Clarion-Clipperton Zone (CCZ) of the Pacific Ocean, assigning a combined net present value (NPV) of $23.6-million to the proposed deep-sea operations.

The first assessment, a prefeasiblity study (PFS) for the NORI-D area in the CCZ, marks a world-first declaration of a probable mineral reserve for a deep-sea polymetallic nodule project, with 51-million tonnes of probable mineral reserves. Measured, indicated and inferred mineral resources exclusive of reserves of 274-million tonnes of wet nodules are expected to provide an additional 113-million tonnes of recoverable nodules once detailed survey and mine planning is complete.

TMC said that, in light of recent US regulatory developments, the company expects to start commercial production in the fourth quarter of 2027, before scaling to an average targeted production of 10.8-million tonnes a year of wet nodules at steady state, over an 18-year mine life.

NORI-D will produce at a steady state production rate of 97 000 t/y nickel, 2.39-million tonnes a year manganese, 70 000 t/y copper and 7 400 t/y cobalt, at a first-quartile cash cost of $1 065/t of nickel, including byprodcuts, and an all-in sustaining cost of $2 569/t.

The PFS has an after-tax NPV of $5.5-billion and an after-tax internal rate of return (IRR) of 27%.

Alongside the PFS, TMC published an initial assessment for the remainder of its resource in the NORI and TOML blocks in the CCZ, with a measured and indicated mineral resource of 73-million tonnes of wet nodules grading 1.30% nickel, 0.20% cobalt, 1.2% copper and 30.2% manganese with an abundance of 12.8 kg/m² and an inferred mineral resource of 1.21-billion tonnes of wet nodules grading 1.30% nickel, 0.20% cobalt, 1.1% copper and 28.7% manganese with an abundance of 11.6 kg/m² supporting an after-tax NPV of $18.1-billion and after-tax IRR of 35.6%.

“The combined NPV of $23.6-billion of the two studies should give investors a better idea of the economic potential of our total estimated resource,” said chairperson and CEO Gerard Barron.

“The PFS takes our NORI-D project economics up the confidence curve and contains the declaration of mineral reserves — these are our first 50-million tonnes with a potential commercially viable path to production, with more to follow as we advance our mine planning work,” he said.

Barron stated that TMC would follow a phased development plan, targeting initial production from the Hidden Gem vessel, with an estimated $11-million of development capital expenditure each from TMC and Allseas.

“This PFS brings us one step closer to responsible production, potentially opening the door to new pools of capital from strategic and government sources, and reinforces TMC’s leadership in this emerging industry.”