The beauty of it being on the seabed is that it's significantly...

The beauty of it being on the seabed is that it's significantly cheaper to extract and lower transportation costs to port. They have been mining diamonds and this is simply utilising their existing business structure and expertise of seabed mining to extract the phosphate off the bottom of the floor.
imo it's a great business model which will still be feasible if/when phosphate prices decline. I also think that the idea of the marine process is what a lot of people are uncertain about and it could possibly weigh on the share price all the way until production however it is very hard to imagine profits being in the dollars per share and the price remaining at these levels (subject to successfully making it to production).