Video footage from a deep-sea mining test, showing the discharge of sediment into the ocean, has raised new questions about the largely untested nature of the industry and the potential damage it could cause to ecosystems as that companies are pushing to begin large-scale exploration of the ocean floor as early as this year.
The Metals Company (TMC), a Canadian mining company that is one of the major players in the industry, spent September through November of last year testing its underwater extraction vehicle in the Clarion Clipperton Fracture Zone, a section of the Pacific Ocean between Mexico and Hawaii.
But a group of scientists hired by the company to monitor its operations, concerned by what they saw, posted video of what they said was a faulty process that accidentally released sediment into the ocean. The scientists also said the company fell short on its environmental monitoring strategy, according to documents seen by The Guardian.
As the push for deep-sea mining intensifies, experts are increasingly concerned that companies will kick up clouds of sediment, which could be laden with toxic heavy metals that can harm marine life. At least 700 scientists, along with France, Germany and Chile, are calling for a moratorium on deep-sea mining.
In a post on its website, TMC acknowledged the incident, but framed the discharge from its cyclone separator as a “minor event” in which “a small amount” of sediment and nodule fragments spilled into the ocean. The company said it fixed the issue on its equipment to prevent further spillovers and concluded that the incident “did not have the potential to cause serious harm.”
In a statement to The Guardian, the International Seabed Authority (ISA), a UN-affiliated agency set up to control and regulate deep-sea mining, said its preliminary assessment “did not identify any threat of harm to the environment “, but was waiting for a more detailed report of the incident from the company.
While many of the technologies used in deep sea mining were developed decades ago, the inadvertent discharge during testing highlights the challenges of adjusting the equipment for use in the field.
Experts and critics warn that the incident highlights the relative uncertainties surrounding deep-sea mining. Companies are scrambling to rummage to the ocean floor for valuable metals, used in electric vehicle batteries and a host of other technologies, such as green energy production, amid a global scramble for stable supplies.
“What we have seen is an unauthorized release, and in land mining, this would have consequences of some kind. And the company says they told the regulator as a courtesy? This is bizarre,” said Catherine Coumans of MiningWatch Canada, adding that the incident goes against company assurances that no sediment will be released near the ocean surface.
TMC, which is based in Vancouver but whose senior staff are scattered across the US and Europe, says it has been exploring vast tracts of the seabed for “polymetallic nodules”, made up of nickel, copper, cobalt and manganese, which they have precipitated out of ocean water over millions of years.
The nodules have long been known to contain critical elements for the construction of batteries and other electronic devices, but their depth meant that extracting them had, until recently, been considered too expensive and arduous.
Big investors now eagerly eyeing deep-sea mining include Danish logistics giant Maersk and multinational commodity multinational Glencore, underscoring the industry’s hopes of discovering new sources of critical metals such as copper. , cobalt and nickel.
TMC’s investor materials suggest the company believes its Pacific mining sites could produce more than $30bn (£24bn) in profit over the next 20 years with minimal damage to the environment. But the push is increasingly controversial: Two years ago, major battery users including Google, Samsung, Volvo and BMW joined a World Wide Fund for Nature (WWF) call for a moratorium on mining the seabed for fear of lasting environmental damage.
Scientists hired by TMC and its subcontractors say the sediment monitoring plan, critical to the company’s approval to begin mining, was developed without fully considering how the sediment columns (debris that is raised from the extraction of the bottom of the sea), and that those in charge of supervising the efforts had little experience working with the plumes.
In one case, scientists observing the tests alleged that a project subcontractor, the DHI company, used a robot to create a disturbance after mining operations did not go as planned. As a result, the scientists called any of the data obtained “uncontrolled and unscientific,” and largely useless.
They also said that DHI tried to “influence independent scientific sampling activities” by directing scientists to take samples when a plume was not present, warning that the deficiencies created a “failed and flawed monitoring operation”. In their notes, the scientists concluded that the data “cannot be considered for any future study and cannot support any model validation or future modeling effort.”
Related: Race to the bottom: the disastrous, blindfolded race to mine the depths of the sea
DHI told The Guardian that testing parts of the water without sediment, known as “out of plume” measurements, is a critical part of the monitoring process to establish the plume boundary. Tom Foster, president of DHI Water and Environment, said it was “highly misleading” to characterize the test procedure as an attempt to “influence” scientific sampling. The company followed “standard industry precautions” to assess samples for potential contamination, he said, and procedures were in place to reject any samples “adversely affected by contamination.”
In a statement to The Guardian, TMC said that as part of its monitoring efforts, samples were taken at various concentration levels from the plume to better understand the “behavior and impact of the collecting system and plume.” The company said it hired “world-leading experts in the field” to oversee the monitoring and dismissed “unsubstantiated” claims of any attempts to manipulate the data.
Critics have long feared that the sediment plumes created from mining could severely harm marine ecosystems by limiting light penetration and releasing harmful toxins. “We don’t know what the consequences of those problems were below the surface of the sea,” Coumans said. “We are only seeing the tip of the iceberg. We are not getting transparency.”