dredging

All the photos of the deposit forwarded by AXZ show it as being on tidal flats and the talk here is about cutter suction dredging and low capex.

The semi diurnal tidal range average in that area is 1.5 metres and that is at the top of the tide, twice a day.
The rest of the time there is no or very little water across the bulk of the deposit.

How then are they able to use a cutter suction dredge, any ideas? Awaiting the PFS.