This is a Canadian mining company that discovered it by partially finding a researcher to investigate. After about 8 years, their researchers literally said "we're forced to conclude that this was caused by the above."
The mining company was not happy, the CAD government put a moratorium on mining for further research, and now the company is paying to have other research completed cuz they "dispute his findings" 😂 I'll see if I can find the article
To be clear, the oxygen source they found is tiny relatively speaking it's just a surprise it's there at all (and even then the measured oxygen level levelled out after 48hrs so it may not even be a continuous source of oxygen under normal circumstances, they theorised that it may have been caused by them stiring up the seabed when they dropped the chambers down)
Iirc it did turn out that certain life was found in far greater abundance in areas with that oxygen source though, its tiny overall but huge for the local environment.
Even without that did you see how he plans to mine them? They're going to drag the seafloor. Which will completely destroy any ecosystem down there. And unlike a strip mine that stays in one location for decades, this is one and done. One day to destroy an area and move on.