Pressures in excess of 2 million pounds per square foot greet you in the deepest parts of the world’s oceans. Miles below the ocean surface, in total darkness, is where companies hope to find and collect mineral riches. But, seabed mining won’t involve digging tunnels or excavating deep pits. Instead, technologically advanced equipment will vacuum through the top six inches of sediment on the ocean floor. The mining vessels will suck up tons of sediments along with polymetallic nodules.

Polymetallic nodules are the economic prize. The rest of the sediments are simply disposable waste with some level of toxins, such as mercury and lead. Nodules can range in size from less than an inch up to five or six inches in diameter. However, despite their small size, contained in those nodules are riches in the form of copper, manganese, nickel, and cobalt. These metals are all valuable commodities and under high demand due to their crucial role in manufacturing efficient modern batteries. 

The technology required to reach miles under the ocean, into bone-crushing pressures, and then suck the ocean floor contents to the surface is sophisticated and cutting edge. The target date for the first deployment of mining vessels is 2020.

A consistent supply of metals to aid in the mass-production of efficient batteries is an important goal. The role of electric vehicles in reducing global carbon emissions is critical in tackling climate change.

What is the downside?

Traditionally the economics of environmental pollution hinge on a model of maximizing profits by deferring waste disposal cost into the future. This transfers the actual disposal cost onto future taxpayers, and lets companies maximize their present-day profits. This process is economically good for us now but bad for our children.

Currently, the waste disposal plans for these seabed mining operations focus on flushing waste sediments back into ocean’s surface waters. A conservative estimate is that each mining ship will discharge two million cubic feet of sediment each day. 

This process introduces two major problems. Toxins in the sediments will poison existing marine life in the sediment plume, and the sediments themselves will also drown or suffocate some of the planktonic (floating) and benthic (sea bottom) communities. The magnitude of the threat from this process is unknown since so little detailed research exists on these deep-ocean ecosystems.

The environmental standards guiding mining operations will be determined by the International Seabed Authority. So, best practice dictates taking comprehensive baseline environmental surveys, and rigorous onboard water treatment to separate sediment and toxins from the seawater. Then, discharged water is closer to pollution-free. But early indications are that this will not happen.

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ArcheanWeb:

The economics of environmental pollution (Source: ArcheanWeb) – https://archeanweb.com/2020/01/02/the-economics-of-environmental-pollution/ Also:

Seafloor ecosystems fare poorly in simulated deep-sea mining (Source: ArcheanWeb) – https://archeanweb.com/2020/05/05/seafloor-ecosystems-fare-poorly-in-simulated-deep-sea-mining/ Also:

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Sources:

History’s Largest Mining Operation Is About to Begin (Wil S. Hylton – The Atlantic) – https://www.theatlantic.com/magazine/archive/2020/01/20000-feet-under-the-sea/603040/