A seafloor bulk mining tool for production cutting of a seafloor bench. The tool uses a tracked locomotion system to travel across a seafloor bench. Power and control interfaces receive power and control signals from a surface source. The tool has a drum cutter for cutting the bench, and a sizing grill adjacent the drum cutter for sizing cuttings as they are produced by the drum cutter. A drum shroud may also be provided to help contain cuttings. A suction inlet can be used to capture cuttings as they are produced, for example in conjunction with a spade and augers.