The cost figure Kristin Hengstebeck gives for her company's nickel is negative $2.40 per pound.
Negative, because the same ore carries cobalt, copper and manganese at grades high enough to sell, and the revenue from those byproducts credits back against the nickel. On the nickel cash curve, she says, that would leave The Metals Company as the second lowest cost producer in the world. The only producer below it would be Norilsk in Russia, whose deposit carries platinum group metals.
Which is a striking thing to say about ore that sits 4,500 metres down in the Pacific Ocean, off the coast of Mexico and short of Hawaii.
Three land based mines in one ore
Hengstebeck brought one of the nodules to the interview.
They sit unattached on the seafloor, and she treats that as the fact everything else follows from. There is no drilling and no blasting. A jet of water is shot at the seabed, the nodule lifts into a robotic collector, and a vertical transport system carries it up the water column to a production vessel at the surface.
Each nodule holds nickel, cobalt, copper and manganese together, a combination she says you would not find on land. Her phrase for it is "three land-based mines in one ore". Nickel drives the revenue; the manganese product also serves steel markets.
The economics she describes follow from the absence of a mine site. There is no fixed infrastructure to put up, and the company can choose where the material gets processed afterwards. The pilot production vessel is an ultra deep water drill ship converted for nodule collection, and that same system is intended to be the first commercial one. The lifting technology was refined in the 1970s and has been improved since, mostly in how the collector interacts with the seafloor. She is clear that this is not a net new phenomenon for anyone who has worked in offshore oil and gas, and that a good deal of the technical expertise sits with Western countries and companies.
The Metals Company holds three exploration licences and has defined the resource on two of them. Those two, on her account, are the largest and second largest undeveloped nickel projects on the planet. It is the only North American company developing the resource.
The comparison she keeps returning to
Asked about the difficulty of working 4.5 kilometres down, Hengstebeck answers by talking about Indonesia.
That is where nickel growth sits today, and the ore is roughly a metre from the surface, which sounds simple until you account for the area it covers. Laterites are among the higher grade terrestrial reserves left, and getting at them means clearing swathes of land. Her term for the result is "rainforest nickel".
Then the waste. Laterite processing generates large volumes of tailings and, in her reading, no good disposal route. Deep ocean disposal has been banned in the coral triangle, which she notes is ironic given the argument she is making. Dry stacking in a wet tropical climate with seismic activity carries its own risk of failure. She adds the effects on communities living near the mine sites, the movement of indigenous people, and a general lack of transparency from producers in the fastest growing part of the market.
Her line for an American audience is that two and a half miles down there are no human communities. The workforce and land use questions that attach to terrestrial mining do not arise, because there is nobody there.
If alternative supply chains are not developed, she argues, Indonesia is where the growth will continue to be. That is the counterfactual she is asking people to weigh her company against.
Twelve years before the application
The route to production runs through the International Seabed Authority, and Hengstebeck is unusually keen on how slow it is.
There are 19 exploration licences for nodules, spread across European and Asian countries and Pacific island states. The Metals Company is sponsored by three Pacific island nations. It has done more than twelve years of environmental baselining and resource definition work, all of it prescribed by the exploration code, with no ability to leapfrog any of it. That builds in a fixed three to five year lead before an applicant can do anything commercial.
That work was due to culminate in the company's application for a commercial licence later in the year the conversation was recorded, followed by an ISA review of about a year. She expects her company to reach market first, with other contractors following in a cadence behind it.
The proof point she offers is from 2022, when the company completed an integrated pilot collection and lifted around 3,000 tonnes. It is, she says, the only contractor to have lifted nodules at that tonnage.
Processing was arranged separately, because, as she puts it, "you can't put these into an electric vehicle". The Metals Company has an agreement with Pacific Metals Co. in Japan to carry out the primary smelting at that company's existing facility, which keeps the capital cost down by using a plant that is already built. A refinery is to be located in the United States.
Why this argument and not the one about open pits
The debate about deep sea mining runs hotter on LinkedIn than the debate about open pit mining, which does not really exist. Hengstebeck's explanation for that is about sequence.
Open pit and underground mining already happen, so there is a baseline of acceptance underneath them. Here the regulation is being written ahead of any commercial activity. The resource is internationally governed as a common heritage of mankind, and around a hundred intergovernmental and NGO entities sit as observers at the ISA, so every stakeholder has a voice in a process that has not produced anything yet.
Her response to the criticism is that the industry cannot be judged in a vacuum. Mining is the single largest producer of waste of any industry globally. The entire mass of a nodule is used, she says, with no toxic tailings and near zero solid waste, which she calls unheard of. On comparative impact, she points to work by Benchmark Minerals and others measuring nodules against existing land based ores and processing methods, which in her account finds this the lowest impact route.
The contrast she draws is between two sequences rather than two technologies. Existing producers, she says, are doing it and then thinking about how to be better, "whereas we are setting a standard before we actually start".
The final argument is about supply. If you accept that the clean energy transition needs a given quantity more of critical minerals, and that degrowth, reuse and recycling are part of the answer, the material to feed that recycling is not yet in circulation. Nodules, in her framing, are what gets a circular economy started on a timeline that matters to the climate argument rather than after it.
This piece draws on the full conversation, which is available with a complete transcript on the episode page.