They haven't presented all of the information you are seeking as...

They haven't presented all of the information you are seeking as yet. From the last corporate presentation. https://patriotbatterymetals.com/presentation/

They were working to a submission this calendar year so we should see all of these questions answered within the next three months.

It was certainly something that put me off initially as well. But looking at the precedents and the process, I was comfortable with the risks being mitigated around the water body. Don't get me wrong there is still a risk around this one, however given the size and strategic nature of the find, along with the infrastructure available to the project, there should be enough in the overall environmental outcomes to outweigh the arguments around not being able to drain the lake and relocate the inhabitants.

From an engineering perspective, I don't believe they will be breaking any new ground either.

They make specific reference to the Renard Diamond Mine. Which is both open pit and underground. (Similar issues facing PMT with a lake at surface and a buried ore body) Refer section 16 in the linked doco below (specifically 16.3).

http://s2.q4cdn.com/850616047/files/doc_downloads/revised_mine_plan/TECHNICAL_REPORT_SEDAR.pdf-Adobe-Acrobat.pdf

Look how deep they are going there. I don't believe we have any water flow data, which is what I understand they are in the process of collecting and collating at present.