As I see it, the spreading at the deep ocean rifts brings fresh magma to or close to the surface and water under very high pressure penetrates extracts minerals. The spreading zone is where these black smokers = minerals dissolved under high temperature/pressure exiting this hydrothermal fluid at which point some minerals can not stay dissolved = black/dark particles that resemble smoke in the water. There are many minerals that stay dissolved in a mixture of oxidation states that are very nutritious to certain bacteria = a bacterial mat which supports a variety of worms/crabs/fish on an ecological chain. The minerals stop flowing 10-50 km?? from the spread and the smokers gradually cease us the minerals stop. The life exists as a variable band away from the spreading zone and after some distance it reverts to a dead zone with little life or smokers. These mineral nodules are formed close to the rift and no more minerals flow after 50-100Km - I expect the zone varies.
If they mapped the zones are gathered nodules outside this 50-100 Km zone - could they gather minerals while not hurting any life forms - bacteria/worms/fish? This spreading has been ongoing for millions of years = stay 500-1000Km away and gather minerals as well as hurt no life. I have seen videos of the plumes from the nodule gathering tests and they make a plume of fine sediments, but they could gather nodules with a screen and filter out the fine stuff and allow metals to be collected with little or zero harm to deep life as long as they stayed far from the vents. Of course = deeper sediments = more filtering needed. It seems to me way to do it is possible.