# Virtual Prototyping of Bulk Material Preparation Devices in Mining Using Multiphysics Simulations
## 1 Introduction
### Practical Usage of DEM  
According to [33], the DEM method has been used in mineral mining and processing since the 1990s. This method is used, among others, to analyze processes related to the transport of excavated materials, crushing, screening, and flotation. One example of the use of the DEM method is the analysis of particle movement on banana flip-flow screens. Understanding the characteristics of particle vibrations contributes to optimizing the technological processes, e.g., via proper generation of vibrations (linear, clockwise, or counterclockwise), as well as the optimal selection of the vibration frequency and amplitude. Inclination of the sieves is also analyzed in the simulation process. As a result of such analyses, the efficiency of machines increases, ensuring the optimal operation [34; 35]. The application of DEM simulations in the screening process is also presented in [36]. In this article, the authors analyzed the method of separating the particles of the sieved material under the impact of vibrations. Analysis of the inertial operation of a cone crusher is another example of using DEM. In [37], in order to optimize the machine's operation and with the aim of reducing the wear intensity of the linings and reducing production costs, the authors decided to carry out the parallel simulations by combining DEM simulations with a crusher model built in the environment for analyzing the systems kinematics and dynamics of multi-body systems (MBS). Another application of co-simulation is the wet vertical stirred media mill model. The aim of the simulation was to predict the wear of each part of the mill, predict energy consumption, and learn the dynamics of both the grinding fluid and the grinding media. The authors in the article [38] presented a computational model consisting of three parts: the first part was a model of the mill structure that was created in a software environment based on FEM; the second part of the computational model was the grinding fluid model, which was modelled using the particle finite element method (PFEM); the last part of the model was the grinding medium model, which was developed in a program based on the DEM. Weak two-way couplings were defined between each model. The distribution of forces was defined by the resistance coefficient as a function of the Reynolds number. A similar approach to co-simulation was described in [39]. In this case, DEM, combined with the method of dynamics of multi-body systems and a novel particle replacement model (PRM), was used to analyze the pellet grinding process and simulate the effectiveness of high-pressure grinding rolls (HPGR). In this case, crushing was not only aimed at reducing the size of the lumps of run-of-mine, but it was also important from the point of view of releasing valuable components from the extracted ore. For a more detailed understanding of the crushing process along with the analysis of interfacial cracking, DEM simulations can also be used. This problem was presented by the authors in [40]. The analysis and development of copper ore crushing processes in hammer crushers, using co-simulation of DEM and PRM methods, was also dealt with in [41]. Another example of using DEM simulations to analyze crushing processes is presented in [42]. The presented simulations performed a comprehensive analysis of the loads in the mantle, the crushing torque, and crushing power in relation to a mining gyratory crusher operating in a copper mine. The process opposite to the crushing process is the granulation process, i.e., combining small particles into larger ones. This is a much more complicated phenomenon than the crushing process. During the technological process, as a result of mixing, movement, or vibration, granulation and crushing of the larger particles may occur at the same time. This phenomenon depends on many physical parameters of the material. The use of DEM simulations to analyze granulation processes is presented in [43].