Abstract: The exploration of No.1 Ore-body in Gangli Iron Mine may result in collapse and water inrush hazards,because of the Gangli River passing by above the surface ground.In order to evaluate the safety of underwater exploration,the geological situation,water bursting passage,rock characteristic and the river bed security were analyzed,meanwhile 3D fluid-solid coupling model of ore-body mining and support is established based on the basic control equation of 3D flow.Through analyzing the stress,strain and flow vector,the risks for collapse and water inrush during underwater mining are evaluated,which has a guiding significance for design and safe exploration of Gangli underwater iron deposit.

Key words: Iron deposit, Under water mining, Fluid-solid coupling, Numerical Simulation