The concept of continuous mining for manganese nodules suggests three sub-operations in total mining: collecting, lifting, onboard treatment. The combination of three components could be shaped by self-propelled seafloor mining robot, flexible conduit and buffer, lifting pumps and pipe, and mining platform. Particularly, the self-propelled robot tracking the mining paths on the seafloor is the key to accomplish the continuous mining. This paper discusses track velocity control of remotely operated mining robot, which is a basic and indispensable requirement for path tracking. The track velocity control is realized by PI controller from gain tuning formulas based on the model identification. First, to investigate the nature of the tracking system, a laboratory test is executed with the robot hung in air by overhead crane. Next, the transfer function of the tracking system is identified by the open-loop response and the closed-loop response. Through familiar tuning formulas based on the identified system parameters, PI gains are tuned. Finally, among the tuned PI gains, the one of best performance is set as the track velocity controller.