New Platform to Monitor the Environmental Impacts of Seafloor Mining

Various unconventional natural resources (e.g. seafloor massive sulfide, methane hydrate and manganese nodules) existing on and under the seafloor will possibly be mined in the near future. When mining these deep sea resources, it is necessary to monitor the environmental impacts of seafloor mining. Environmental impacts have been usually monitored by mooring systems or stations put on the seafloor. Mooring systems consist of floats, sinker and sensors. Their heights rang e from one hundred meters to several kilometers. In order not to entangle in the mining machine and the support cable, it is impossible to put the mooring systems within the distance of their heights from points of the operation safety. The stations consist of a frame and sensors. Their heights are about a few meters. Therefore, we are able to put the stations near the mining point, but we can’t observe the upper water layer. In this study, we have developed a new platform to observe the environmental condition near the mining point and the upper layers of the seafloor. The developed platform consists of frame, sinker, releaser, winch, battery and sensor assembly. Because the size of this is 2 × 2 × 2 m, we can put this near the mining point. The sensor assembly is moved from the seafloor up to 150 m by the winch. This platform can automatically observe the environmental condition for several months without external power supply by using the internal battery. Therefore, we can automatically observe the environmental condition near the mining point and the upper layer by using this new developed platform. The platform is also effective for environmental monitoring near deep-sea petroleum exploitation points.