Certificate of occupational health and safety management system

Dredging is an underwater earthwork excavation project that uses manpower or machinery to dredge, expand or excavate deep rivers, lakes and other waters. For a long time, channel dredging has been an

Sunken ship salvage in underwater salvage: six different methods can be adopted according to the size of sunken ship and the specific location of the event. However, various methods can be used alone,

1. Underwater search: two search team members in each group enter the water in the order planned in advance. The team member who arrives at the bottom table first must wait until another team member a