With the announcement in May 2019 to form a strategic partnership with DeepGreen, Allseas made its first tentative steps into the deepsea mining industry. Ten months later, a former drill ship was acquired to convert into a collection vessel for polymetallic nodules. This year, key elements of the collection system will be ready.

Allseas is a renowned contractor with highly advanced technology in the offshore energy market, specialised in the design and execution of large and complex offshore projects for major oil and gas producing companies worldwide.

Driven by its pioneering spirit, the company entered into the partnership with DeepGreen, a Canadian mining company at the forefront of deepsea polymetallic nodule collection. These nodules, which lie unattached on the deep-ocean floor, contain high concentrations of critical metals needed to produce batteries to power electric vehicles and store energy from wind and solar energy.

As the technology provider, Allseas is leveraging its deep-water expertise and innovative capability to develop technology to responsibly recover polymetallic nodules from the ocean floor and transfer them more than 4.5 kilometres to the surface for transportation to shore.

Nodule collection system

The collection system comprises a polymetallic nodule collector, a vertical transport system and nodule collection vessel Hidden Gem. Detailed design of the mineral collector – a steel frame with tracks, processing equipment and pick up nozzles – nears completion.

Particular focus has been on weight and structural integrity. The collector must be robust enough to operate 24/7 under extreme pressure, but remain light enough to manoeuvre efficiently and effectively in the soft soil conditions on the seabed. Construction of the collector commenced mid-February with delivery targeted for October 2021.

Also read: Seatools to supply crawler equipment for Allseas’ deepsea mining project

In parallel, firm progress has been made with the airlift system that will transport the nodules to the surface. The system comprises a 4.5-kilometre-long riser, deployed from the Hidden Gem and connected to the collector vehicle via a shorter flexible hose. The mineral-bearing nodules are separated from sediment inside the collector vehicle and floated up the riser pipe to the surface. The nodules will then be transferred from Hidden Gem onto cargo vessels for transportation to shore.

Hidden Gem

Allseas acquired the former ultra-deepwater drill ship Vitoria 10000 in February 2020 for conversion to accommodate the nodule collection system. Renamed Hidden Gem, the vessel is 228 metres long and 42 metres wide, and can accommodate a crew of 200. Reactivation of the vessel has started in Norway. Onboard systems have been overhauled and upgrades of the accommodation are in full flow.

Also read: Allseas acquires drill ship for deepsea mining

In July, Hidden Gem heads to Tenerife for drydock modifications ahead of a collector “wet-test” in the Atlantic at the end of 2021 and the official start of pilot mining tests in the Pacific, 1200 nautical miles west of Mexico, in 2022.


In the meantime, strategic partner DeepGreen made a significant step forward. In March, it merged with Sustainable Opportunities Acquisition Corporation (SOAC), a special purpose acquisition company focused on acquiring companies with a strong environmental, social and governance orientation. The combined company, to be renamed The Metals Company, will generate additional investment necessary for the next stage of the journey to become leaders in the production of electric vehicle battery metals.

This article was supplied by Allseas and published in SWZ|Maritime’s May 2021 deepsea mining special.

Pictures by Allseas.