Fragmentation Characteristics of Seafloor Massive Sulfides: A Coupled Fluid-Particle Flow Simulation

Abstract

The research on the fragmentation mechanism of seabed minerals under high ambient pressure significantly contributes to the exploitation of seafloor massive sulfides (SMS). In this paper, the uniaxial compressive strength (UCS) test and triaxial compressive strength (TCS) test were carried out on two kinds of SMS samples to obtain the key mechanical properties of minerals, including cohesion, internal friction angle, compressive strength, and elastic modulus. Then, based on these mechanical parameters, the fluid-solid coupling cutting model of two SMS samples at high ambient pressure is established by using the coupling method of discrete elements and smooth particles. A mixed-bond model is selected, and the microscopic parameters are determined by a repeated calibration process. Meanwhile, the cutting force and debris information are monitored and collected in real time during the whole cutting process. The results show that under different confining pressure environments, the model shows the transformation of minerals from brittleness to ductility. The cutting force increases with the increasing ambient pressure. Due to the fluid pressure, the crushing mechanism tends to shear failure, which is more likely to produce mud and finer fragments.