9 Subsea Mineral Harvesters

Deep-sea mining is rapidly developing, and a variety of different companies and research institutions have been developing harvester and collector technology to mine these resources.

Deep-sea mining involves operating equipment under tremendous pressures, at depths of around 5-6000m, in total darkness. Pressures at these depths are tremendous; for example, most military submarines operate at depths of around 5-600m and would be utterly crushed by the pressure at the depths that harvesters are designed to operate at.

Here's a list of the 9 most interesting subsea mining machines that are being developed, tested and used:

Apollo II

Apollo II harvester was developed over 2-1/2 years by Blue Harvesting, a collaborative project involving nine institutions across five countries to design, build and test a machine a harvester with minimal environmental impact.

Apollo II was tested in 2022 at a water depth of around 300m just South of the coast of Spain. It collected a variety of artificial nodules that had been placed on the seabed. Further testing is planned on real polymetallic nodules in the Northeast Atlantic Ocean.

COA Harvester

In 2021, a number of organizations operating under the China Oceanic Association developed a polymetallic nodule harvester along with lift equipment. These included the Changsha Research Institute of Mining and Metallurgy, the Changsha Research Institute of Mines, Central South University, and other dozens of others.

The harvester was tested along with a 1300m riser lift system in July of 2021, which harvested and raised a total of 1166kg of polymetallic nodules

China Oceanic Association polymetallic nodule harvester

Eureka II

Eureka II is a harvester being developed by Impossible Metals, a California and Canada-based technology company.

Eureka II uses a complex system of automated arms to pick nodules off the seafloor, and so is unique amongst harvesters listed here. This technology is purported to give various benefits around selectivity and avoiding harvesting nodules with organisms attached.

Eureka II was tested to a depth of 1800m without a tether off the coast of Florida in May 2024.

Impossible Metals Eureka II deep sea mining harvester

Kaituo 2

Kaituo 2 was developed by Shanghai Jiao Tong University. It has undergone a total of five test dives, including one to a depth of 4100m in the Western Pacific.

Kaituo 2 is unique amongst harvesters in that it is able to sample all three types of subsea minerals. It is equipped with a drill, collection system and ore storage, and it can operate autonomously on the seabed across rough, rugged terrain and steep slopes.

Kun Long 500

China has been engaged in researching polymetallic nodule harvesting since the 1980s. In 2018 the Changsha Research Institute of Mining and Metallurgy and Central South University completed the development of "Kun Long 500".

Kun Long 500 completed sea trials in the China South Sea at a water depth of 514m, which tested the crawler walking mechanism and the hydraulic collection of nodules with a 1/10th scale hydraulic collector.

Changsha Research Institute of Mining and Metallurgy Kun Long 500 polymetallic nodule harvester

MineRo I & II

Korea Institute of Ocean Science and Technology (KIOST) developed the MineRo I and II harvesters from 2007 to 2013. The harvesters and lift system were tested to a water depth of 1370m and collected a total of 1535tons of polymetallic nodules from the seafloor.

Patania II

Patania II is a polymetallic nodule harvester that has been developed by GSR (a subsidiary of the Belgian DEME group) and the German Federal Institute for Geosciences and Natural Resources (BGR).

Patania II was tested to a water depth of 4500m in 2019, and collected nodules at a rate of 110-120t per hour. It was subsequently tested in GSR's contract area in the Clarion-Clipperton Zone in May 2021.

Patania II deep-sea mining polymetallic nodule harvester

TMC's Harvester

The Metals Company (TMC) has been developing and refining their polymetallic nodule harvester for many years, and has one of the most advanced and best understood harvesters.

Significant tests were carried out in 2022 on polymetallic nodules in the Clarion-Clipperton Zone in the Pacific. These included the harvesting of around 3000t of nodules and the recovery of these nodules to surface using a riser system. Follow-up studies were performed in 2023 and 2024 to ascertain the impact on the ecosystem around the area harvested.

The Metals Company's deep-sea mining polymetallic nodule harvester

Varaha

The National Institute of Ocean Technology (NIOT), India, has been developing subsea mineral harvesting equipment for decades. They conducted a number of partial sea trials of a subsea mining system in 1996 (at a depth of 410m) and in 2006 (at a depth of 450m).

The Varaha harvester was developed thereafter, and was successfully tested in 2022 at a depth of 5270m in the Central Indian Ocean. Varaha collected polymetallic nodules from the seafloor during this test, and further testing is planned in combination with a lift system.