Expedition Summary

July 31-August 12, 2022, the Bureau of Ocean Energy Management (BOEM), the U.S. Geological Survey (USGS), and NOAA Ocean Exploration explored a site on the Blake Plateau off the coast of Georgia. The purpose of the expedition was to better understand the long-term environmental impacts on the seafloor and water column of experimental deep-sea mining technologies used at the site in the 1970s and the implications for future deep-sea mining activities.

Ocean Infinity operators prepare the HUGIN autonomous underwater vehicle for launch during 2022’s Investigation of an Historic Seabed Mining Test Site on the Blake Plateau.
Ocean Infinity operators prepare the HUGIN autonomous underwater vehicle for launch during 2022’s Investigation of an Historic Seabed Mining Test Site on the Blake Plateau. Image courtesy of Investigation of an Historic Seabed Mining Test Site on the Blake Plateau, NOAA Ocean Exploration. Download largest version (jpg, 4.7 MB).
The HUGIN autonomous underwater vehicle is launched from Motor Vessel Deep Helder to survey the seafloor of the Blake Plateau during 2022’s Investigation of an Historic Seabed Mining Test Site on the Blake Plateau.
The HUGIN autonomous underwater vehicle is launched from Motor Vessel Deep Helder to survey the seafloor of the Blake Plateau during 2022’s Investigation of an Historic Seabed Mining Test Site on the Blake Plateau. Image courtesy of Investigation of an Historic Seabed Mining Test Site on the Blake Plateau, NOAA Ocean Exploration. Download largest version (jpg, 4.8 MB).

In 2019, an expedition on NOAA Ship Okeanos Explorer mapped and briefly explored the site via remotely operated vehicle, collecting baseline data about the condition, biology, and geology of the site to inform and spur further research. In 2022, scientists returned to the site on Ocean Infinity’s Motor Vessel Deep Helder to get a closer, more in-depth look at the site.

Even though approximately 50 years have passed since Deep Sea Ventures Inc. deployed their system to collect seafloor sediment and manganese nodules at the site, the team observed extensive and well-preserved bottom scarring. In addition, they noted little to no marine growth on the “patio blocks” installed as markers by the USGS in the early 1980s to help them evaluate the environmental conditions in the area. Still, despite the human impacts and the strong currents of the Gulf Stream, a number of marine animals, including fish, corals, and sponges, were observed in the area.

Seen during 2022’s Investigation of an Historic Seabed Mining Test Site on the Blake Plateau, along with a skate (look closely), manganese nodules like these were the subject of an experimental deep-sea mining pilot project in the 1970s.
Seen during 2022’s Investigation of an Historic Seabed Mining Test Site on the Blake Plateau, along with a skate (look closely), manganese nodules like these were the subject of an experimental deep-sea mining pilot project in the 1970s. Image courtesy of Investigation of an Historic Seabed Mining Test Site on the Blake Plateau, NOAA Ocean Exploration. Download largest version (jpg, 4.6 MB).

To evaluate the use of remote sensing technologies (e.g., sonar) for this type of work, the team equipped Ocean Infinity’s HUGIN 6000 autonomous underwater vehicle (AUV) with a multibeam sonar system, an extensive suite of geophysical sensors, and a subsea imaging system. Programmed on the surface, the HUGIN performed seven pre-planned dives at the site to depths of 780-820 meters (2,559-2,690 feet), collecting an impressive amount of accurate and varied data, including high-resolution mapping data (1 meter and better) and images, with each dive.

These new data enabled the partners to confirm the anticipated seafloor damage, locate 39 of the USGS’ 100 patio blocks (based on an initial analysis), and develop a precise, cost-effective sampling design and methodology for future data collection at the site. BOEM and the USGS will further analyze these data to quantify the extent of the impacts, search for visual signs of recovery, plan for additional research, and, ultimately, inform reviews, future decisions, and mitigation measures related to deep-sea mining in other areas.

This expedition continued a long tradition of interagency collaboration. NOAA, BOEM, and the USGS have been working together to explore the ocean off the U.S. mid-Atlantic and southeast coasts since 2012’s Atlantic Canyons Undersea Mapping Expeditions. While BOEM and the USGS led the scientific operations for the partners’ 2022 return to the Blake Plateau, Sam Cuellar, an expedition coordinator with NOAA Ocean Exploration, joined the expedition to observe and document the HUGIN operations and evaluate how the AUV, or other similar AUVs, could be incorporated into NOAA Ocean Exploration’s operations.

Mike Rasser of the Bureau of Ocean Energy Management (left) and Jason Chaytor of the U.S. Geological Survey (right)  review data collected by the HUGIN autonomous underwater vehicle from the study area of Motor Vessel Deep Helder during 2022’s Investigation of an Historic Seabed Mining Test Site on the Blake Plateau.
Mike Rasser of the Bureau of Ocean Energy Management (left) and Jason Chaytor of the U.S. Geological Survey (right) review data collected by the HUGIN autonomous underwater vehicle from the study area of Motor Vessel Deep Helder during 2022’s Investigation of an Historic Seabed Mining Test Site on the Blake Plateau. Image courtesy of Investigation of an Historic Seabed Mining Test Site on the Blake Plateau, NOAA Ocean Exploration. Download largest version (jpg, 4 MB).
Seafloor disturbance is evident in this photomosaic, which represents a section of seafloor about 8-by-26 meters (26-by-85 feet) in size. It’s a fraction of the many kilometers of disturbance observed during 2022’s Investigation of an Historic Seabed Mining Test Site on the Blake Plateau.
Seafloor disturbance is evident in this photomosaic, which represents a section of seafloor about 8-by-26 meters (26-by-85 feet) in size. It’s a fraction of the many kilometers of disturbance observed during 2022’s Investigation of an Historic Seabed Mining Test Site on the Blake Plateau. Image courtesy of Jason Chaytor, U.S. Geological Survey. Download largest version (jpg, 8.1 MB).

Published September 19, 2022

Investigation of an Historic Seabed Mining Test Site on the Blake Plateau contributed to the National Strategy for Exploring, Mapping, and Characterizing the United States Exclusive Economic Zone and Seabed 2030 .