From November 8 – December 4, 2025, 9 CSSF team members supported the Korean Institute of Ocean Science and Technology (KIOST) aboard the R/V Isabu for their 2024 Pacific Ocean Expedition, which is part of a continuing program to survey remote seamounts for rare earth minerals in the Western Pacific Ocean. [Add: More context from the science team]. Our team’s objectives were to both conduct video transects and execute crust coring at the seamounts of interest using our Korean Remotely Operated Coring System (KROCS).

This expedition had one leg with two parts: 1) geological coring and drilling and 2) biological sampling. To do this work, KIOST must secure seafloor leases from the International Seabed Authority (ISA), and after a certain number of years, they have to give a certain percentage of the lease back. With the timing of the program, this means that our team must collect 100 cores per year to meet the science team’s schedule. During the surveys and drilling, the scientists could tell how much pressure the sediment has undergone by its colour and, as a result, whether we should keep going forward or stop. In the end, we were able to collect 130 cores, which exceeded the science team’s expectations! For the second part of the leg, we assisted in conducting biological surveys to look for target species. Our team flew ROPOS around the periphery of the seamounts of interest to look for key species (of corals, sponges and shrimps), collected imagery for photogrammetry (on corals and sponges), and placed settlement plate tiles at selected locations on the seamounts.

[Add: Highlights for the science team]

Will Glatt, CSSF’s Science Manager (at the time) emphasized that this was his favourite expedition ever. He noted that there was great performance from the crust drill and that the mission was packed with personal highlights, including seeing a Bigfin (Magnapinna) Squid and “sweet” sunsets (one following a thunderstorm). Our team brought, what we think is, a fossil of a fish up in one of the core samples, which Will noted was the “coolest thing [he] had ever found subsea”. This expedition was also the first time he had worked with Luke Girard, Mechanical Technician (at the time) as a shift supervisor. He said that he found it easy to work with Luke and that he really enjoyed it!

Our team faced one challenge on this mission. KIOST owns the KROCS drill, which they take home every year, and this time, the spare parts were accidentally left back in Korea. Unfortunately, one of the hydraulics hoses failed. In the equatorial Pacific Ocean, it gets hot. So, everyone has to act quickly to prevent ROPOS from overheating, and the ambient heat makes it hard to run the hydraulics for a long period of time. Our team tested the KROCS coring system on deck and determined that the lateral shift hydraulic function (for changing tools) wasn’t working. With no KROCS spares onboard, preventing us from quickly replacing the hose or swapping out the valve, we had to scavenge ROPOS’s hydraulic spares for parts. We managed to replace the hose and substitute one of our valves for the failed one, turning things around quickly for the client!