Shenyi had some good points on this. If you look at all the RE efforts since the REE card with Trump, they're mostly concentrated into two types:....
1. Mining, which this pulling up mud from 6000m under the ocean falls into as well
2. Turning the refined RE powder into finished products like magnets
Those two steps China are dominant in but not overwhelmingly. The key step between those two where China is actually overwhelmingly dominant in is turning the ore into refined (the #N stuff) powder. There doesn't seem to be much serious effort going on here, only small experimental scale projects.
If you think about all the pitfall of this extracting mud from ocean floor business:
1. This is an experimental ship doing an exploratory thing, it's very far from actual commercial scale mining
2. Can you actually mine REE rich mud from 6000m under the ocean, what is the point when REE mines elsewhere already exist and on land?
3. Once you pull this mud up to the surface, it's at best 0.7% rare earth, how are you going to concentrate it?
4. Even if you do solve the above 3 problems, how would you protect this technology from US who will surely try to take it for themselves with any means, up to using kidnapping

