Mechanical Tests and Numerical Simulations for Mining Seafloor Massive Sulfides

Abstract

With the decrease of primary resources in recent years, deep seabed mineral resources, especially the massive sulfides, are of extensive research significance. In this paper, firstly, the uniaxial compressive strength (UCS) test and triaxial compressive strength (TCS) test on the seafloor massive sulfides (SMS) samples from three different segments are conducted to obtain the key mechanical properties, including the cohesive force, internal friction angle, compressive strength, elastic modulus and Poisson’s ratio. Then, by leveraging the PFC3D code, the uniaxial and triaxial numerical simulations of SMS are performed. During this process, the micro properties in the simulation are altered through a calibration process until they match the macro properties of the SMS samples measured in the laboratory tests. Finally, the micro properties are applied to simulate the cutting process of single cutting pick and two adjacent cutting picks; meanwhile, the cutting force in the fragmentation process of SMS is monitored and collected. This research can provide some guidance for the mining simulation of SMS and effectively predicting the maximum force on the cutting pick.

Experimental Study on Failure Mechanical Properties of Two Kinds of Seafloor Massive Sulfides

“…In order to reduce the influence of non-uniformity of material properties on test data, the average value of data under the same confining pressure is used in data fitting. Figure 13a illustrates the growth rate of axial peak stress with confining pressure is somewhat lower than the respective value shown in Figure 13b from the literature [32], although the data in the literature were measured from different single samples. The data in this linear regression analysis only include the triaxial compressive strength under different confining pressures and the uniaxial compressive strength can be predicted by the fitted curve.…”

“…Figure13. Relationship between peak stress and confining pressure of (a) small-scale specimens and (b) standard specimens[32].…”

Deep Seabed Mining: A Note on Some Potentials and Risks to the Sustainable Mineral Extraction from the Oceans

“…In addition, the changing consumption patterns in the developing world will further impact the global demand for all resources, including minerals. There is a growing demand for strategic metals such as cobalt, nickel, copper, and manganese because their terrestrial reserves are fast depleting [2,3]. Although some lab-based alloys can substitute minerals used by industries, this has limitations regarding capacity and quality, so mining activities will inevitably continue.…”

Added Cutting Teeth to Promote Surface Crack Incisions for Cutting Sandstone

“…Rock chips and indentation forces, closely relating to indentation e ciency and tool wear, are two critical indexes. For the conical indenter, Dai et al (2019) rst tested the mechanical properties of the sea oor massive sul des and then predicted the indentation force in the mining process. Similar numerical simulations by Li et al (2017) indicated that tensile internal cracks are common in the cutting process.…”