Nowadays designing of selected areas of mines underground workings can be effectively improved by the application of computer techniques: 3D scanning, computer simulations and Virtual Reality. This, in fact, would result in the more reliable design process, significantly reduced designing costs and efforts, and improvement of the mines staff’s safety. This scientific paper presents a method developed for redesigning of selected areas of mines underground workings in which auxiliary transport is carried out. The method combines 3D laser scanning technique with computer simulations carried out in a CAD/MBS system, in order to determine the location of potential collisions of the transported loads with the arch yielding support and the equipment. The obtained results, visualized using Virtual Reality, will form input data in the process of designing the selected area of the mines underground workings. Finally, an example of the application of the described method during transportation of big-size load is given.
The method of increasing the efficiency of using one of the most common means of auxiliary transport in underground coal mines—suspended monorails—is presented. Increase of velocity is one of the key parameters to improve the efficiency and economical effect related with the underground auxiliary transport. On the other hand, increasing the velocity results in bigger value of force acting on the suspended monorail route and its suspensions. The most important issue during increasing the velocity is ensuring the required safety for the passengers and not overloading the infrastructure. In order to analyze how increasing velocity influences the level of loads of the route suspension and the steel arch loads, the computational model of suspended monorail was developed. The computational model included both the physical part (embedded in the program environment based on the Multi-Body System method) and the components of the monorail control system. Two independent software environments were cooperating with each other through the so-called co-simulation. This model was validated on the base of results obtained on the test stand. Then, the numerical simulations of emergency braking with different values of velocity were conducted, which was not possible with the use of physical objects. The presented study can be used by the suspended monorail’s producers during the designing process, and leads to increase the safety on underground transportation routes.
This paper presents the process of virtual prototyping of bulk material preparation devices in mining using numerical simulations of multi-physics phenomena. The discrete element method (DEM), meshless method (MFree), and computational fluid dynamics (CFD) were used in the calculation process. The importance of the extraction process and the practical application of DEM in various industries are discussed. The main contact models between particles and how structural material wear is modelled in DEM are presented. The structure of the computational models in DEM and CFD environments is presented. For the validation of the bulk material computational model, bench tests were carried out to determine the material properties (aggregate: five grades, 0–16 mm; coal concentrate: five grades, 2–32 mm; and so-called raw coal, grade 2–8 mm). The bulk density and angle of natural repose were measured, along with determination of the internal and external friction coefficients. Simulations corresponding to the laboratory tests were carried out. Numerical calculations were carried out for the side chute (results—velocities of the particles, compressive forces in the particles, determination of the wearing process) and for the coke classification line (two lines were assessed according to different aggregate sizes and densities of the bulk material). These multi-physics calculations required a combination of DEM-MFree and DEM-CFD methods. Based on the obtained results, it was possible to evaluate the performance and efficiency of the assessed machines.
Method for virtual prototyping of cabins of mining machines operators is presented in the light of anthropotechnical assessment criteria. Anthropotechnical criteria and design of models of anthropometric features, which are used for assessment of design solutions in the aspect of safety criterion, are divided and discussed. Developed virtual prototyping method for assessment of cabin of underground locomotive operator was used. Initial simulation was made with use of Finite Element Method.
In many industries, there is a continuous high demand for skilled welders. Practical training in welding is cost- and time-intensive. To reduce this problem, VR welding simulators have been developed in recent years. They vary in terms of portability, hardware and software components, and functionalities. In this paper, a VR simulator to support practical training in MIG/MAG welding, as a highly portable and affordable solution, is presented. Its only hardware components are an off-the-shelf mobile VR set, a welding torch, and welding coupons that are manufactured using the FDM 3D printing method. The software part is accessed and used via an Internet browser. An important feature of the simulator is also the possibility to differ immersion in the working environment while carrying out virtual welding, which makes the solution also usable for users prone to cybersickness. The VR welding simulator was refined based on feedback obtained during pilot tests. The test participants found it a useful aid for welders’ training, which justifies further work on its development and integration into the teaching of welding in educational and training units.
The permissible speed of suspended monorails in underground mines is determined by the internal regulations of each country and depends on the type of transportation. In the case of passenger transportation, the maximal driving speed in Polish underground mining regulations is 2 ms−1. Regarding the higher permitted driving speed in other countries, it is reasonable to consider changes to these regulations that would raise the permitted speed limit. Increasing the permissible travel speed would improve the efficiency of mining operations because of the significant reduction in the inefficient working time of miners traveling on the monorail from the shaft to their place of work. However, at the same time, an increase in the permissible speed of travel results in higher values of forces and accelerations affecting both the crew riding the train and the underground working infrastructure (the suspended route, slings, and arches yielding support). The results of the series of works carried out at the KOMAG Institute of Mining Technology to assess the impact of increasing the speed on the safety of both the crew and the mine infrastructure are presented in this article. For this purpose, several numerical simulations were conducted, considering the emergency braking of the suspended monorail during which the overloads are the greatest. The result of the simulations was the analysis of the effects of driving and emergency braking of the suspended monorail with increased travel speed on the following: the overloads acting on the crew being transported and the forces acting on the suspended monorail route, including the forces in each sling. Next, a potential solution for improving safety was developed. The development of the algorithm for an innovative method of sequential emergency braking of the monorail in the case of passenger transportation was one of the important solutions.