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Anthropogenic activities related to mining generate both progress and a vast amount of waste that is responsible for environmental degradation. The Jiu Valley is one of the areas of Romania where mining has affected large areas of land, used to build mines and tailings ponds. The former Coroiesti coal processing plant (CCPP) is such a location with a total area of 25 ha containing approximately 5.5 million tons of tailings. The assessment of the stability of tailings dams is extremely important from safety and environmental aspects. This study proposes a solution based on numerical methods for determining the stability of a section of the dam of a tailings pond. The model of tailings pond no. 1, compartment B, from the Coroieşti Coal Preparation was built using COMSOL Multiphysics. Two scenarios of stability analysis were conducted on a section of the tailings dam: the FOS was determined using the shear strength reduction (SSR) method for both the initial and the current state of this TP. This method is a modern alternative to the limit equilibrium method, and its implementation by COMSOL is new to our country, thus aligning this methodology with current worldwide trends and developments in the field. The results obtained proved to be in line with those calculated in the past with traditional analytical methods, proving that the safety criteria of the studied TP/TD are being met. [ABSTRACT FROM AUTHOR]

Operation of vertical transport installations is based on adjustable electrical drive systems which must ensure the technical conditions regarding the variation in time of the speed, the current of the main motors and the accelerations at start and brake phases. Electric drives are part of the fast process of automation equipment. In the case of a vertical transport installation, speed is the characteristic which has to be controlled in command phase, while the dependent factor is the tachograph. The adjustment determines the dependence of the quantity in the process – based on a default law - with respect to the independent quantities and also to the process dependents, thus reducing the influence of the perturbations to the process. There are different ways to define the stability of an automatic system. The balance survey / analysis also approaches the determination of the functions of variation in time of the main actuation motor current and speed (main motor rpm), at the moments of starting the vertical transport installation, and the study of the variation in time of the speed in the case of a load shock. To perform calculations needed for stability assessment and draw all the diagrams a Turbo C 2.0 program was written by the authors.

The bucket wheel excavator (BWE) is a complex continuous digging machine, used to excavate material using a layout of buckets installed on a rotor (bucket wheel), and at the same time, using the conveyor system installed on its boom, transferring this material to the main conveyor. The bucket wheel is the operating equipment, and it rotates in the vertical plane and performs (with the boom) a pivoting movement in the horizontal plane and an ascendant – descendent movement in the vertical plane. The paper presents a new grafo-numeric method of determination of the operation power of the BWE rotor, using computer simulation in SolidWorks. The aim of using virtual models for the analysis of the operation of some components of the BWE is to reduce the specific energy consumption during cutting while maintaining the installed operation power of the rotor, to increase the excavation capacity and to improve the cutting – loading system.

An important feature of the drums of mine shearers, is the material loading capacity onto the armored face conveyor. This characteristic is influenced by both the shape of the vane and the pitch of the helical vane. Thus, the pitch of the helical vane can be either constant or variable. This variable pitch can also have two variants. The first one is with an axial pitch when there is a progressive increase in the pitch of the helical vane towards the conveyor direction, thus resulting in a productivity increase of 15-20% compared to drums with a constant pitch. This constructive variant does not ensure the placement of the cutting picks to achieve a balanced working regime. The second constructive variant is with a radial pitch when the helical vane profile has a variable height along the generating curve. This constructive variant is considered more advantageous, ensuring a more rational placement of the cutting pitch by maintaining a constant axial pitch. In this paper a modeling is proposed for the drum of the CA-1 longwall shearer with variable axial-radial pitch. [ABSTRACT FROM AUTHOR]

The maximum internal pressure developed during the ignition of the explosive mixture with air within the encapsulation is directly dependent on the volume released through clearances or other discharge devices, if present. Consequently, the increase in explosion pressure must be correlated with the study of explosion-proof joints to prevent the transmission of the explosion through clearances to the ambient atmosphere. Through a comparison of defects observed during dynamic explosion tests and checks with static overpressure, a safety factor simulating the explosion demands has been identified. By checking the static overpressure at a certain pressure increase factor, the encapsulations are no less stressed than during an explosion. It has been determined that an overpressure increase factor of 1.5 times above the maximum reference explosion pressure value, during hydrostatic testing, ensures the mechanical stress of the encapsulation equivalent to the stresses resulting from overpressure through explosion. This paper presents the mechanical stress simulation of the explosion-proof encapsulation with a cylindrical frame using the SOLIDWORKS application. [ABSTRACT FROM AUTHOR]

The shield of the SMA-2 utilizes a quadrilateral mechanism with a corner cylinder generating a lemniscate. The synthesis of the quadrilateral mechanism, its geometric and kinematic analysis in correlation with the geometry and kinematics of the entire support, raises challenging analytical issues. For this reason, in the present work, we have theoretically and practically analyzed the geometry and kinematics of the mechanism, demonstrating the utility of using computer software for modeling and simulation in addressing these problems. [ABSTRACT FROM AUTHOR]

In the paper, we addressed the simulation and numerical modeling of deformation under static loading of wire ropes used in mine hoisting installations. We presented the main types of extraction vessels (cages and skips) commonly used in the mining industry, as well as the fastening devices to the hoisting rope (DLC). A review was conducted on the primary structural models of traction cables equipping mine hoisting machines. As one of the critical assessments performed on cables in mining extraction is done at maximum static load, we constructed a virtual model of a tension testing stand for a hoisting cable using SOLIDWORKS®. Essentially, we created a virtual device in the form of an assembly consisting of multiple parts, establishing geometric connections between them. Additionally, we highlighted the cable's path over the core of the fastening device. The actual tension test was performed through a simulation under static loading of a 500 mm section of the cable. We determined the von Misses stress and overall deformations of the cable section. [ABSTRACT FROM AUTHOR]

Longwall mining shearers equipped with drum-type mechanisms have become widely applied equipment in underground coal exploitation. The constructive evolution, quality, reliability, and functional performance of these machines, influenced by technological advancements in materials and manufacturing, is nonetheless overshadowed by their adaptability to various geological and mining conditions, particularly concerning the parameters of the cutting mechanism. A judicious correlation of geometric, dimensional, kinematic, and functional parameters with the characteristics of the coal seam provides a vast field for research. For this reason, we have approached this type of equipment, with special emphasis on the working components, in a study where computer-based methods can prove their utility. [ABSTRACT FROM AUTHOR]

The automation of the multi-rope hoisting devices requires, in a first stage, the working out of the automatic control system of the main work parameters, and then, on the basis of their interpretation, the working out of the reaction loop: computer - hoisting installation. The singular and the global interpreter of the dimensions corresponding to the main work parameters at the local of the computer through a suitable soft, the comparing of the admissible maximum or minimum values, allows the command of the hoisting installation through the computer. The paper contributes to the minimizing of the human factor intervention in the work of the hoisting installation leading to the increasing the safety in exploitation and the command through a numerical computer leads to the decreasing of the dynamic stresses at the mechanical parts are subjected during the exploitation, what means a growth of the transport capacity. [ABSTRACT FROM AUTHOR]

Mine winding systems are a complex set of machines, devices, and mechanisms, which work together both to transport useful mineral substances or tailings from the mine to the surface or to other horizons, as well as to transport personnel, materials, and equipment, from surface to underground. The mine winding systems consists of the actual mine hoisting machine, the head-frame, cables (ropes), conveyances, auxiliary equipment, control and safety devices. The braking system can operate as service brake or safety brake. The service brake acts on the rope wheel to achieve the required tachogram, while the safety braking occurs independently of the operator's will, in the following situations: the lack of power supply, the decrease in the pressure of the hydraulic fluid, over winding of the conveyances, exceeding the maximum permitted extraction speed. A functional condition imposed on the brakes of a mine windings system is to ensure the immobilization of the conveyances after a safety braking. This paper proposes a study of the stresses and deformations to which the drive wheel drum of a single-rope friction mine hoist is subjected to, when it must keep the conveyances immobilized following a safety braking. To solve the mentioned problem, a virtual model of the drum of such an installation was created in SOLIDWORKS. [ABSTRACT FROM AUTHOR]

The processes and technologies for supporting the roof of underground mining works have advanced during the years, thus fundamental changes resulted in both the roof control and the exploitation from economic and technical points of view. The support of the underground excavation roof is carried out by two methods, namely using individual supports, usually metal beams and props, or hydraulic powered supports/shields, the latter representing the most up-to-date technology. The paper presents a virtual model of a powered roof support section made in SOLIDWORKS. For its components a mechanical analysis was performed through the static simulation of the pressure of the roof on the support beam. [ABSTRACT FROM AUTHOR]

The movement of a vehicle is determined by the use of the energy transmitted to the wheels, from the engine through the chain: gearbox - differential. Traction force, resistance forces and inertial forces determine the character of the vehicle's movement. In this paper, I approached the study of air resistance to the forward movement of a vehicle using the calculation technique. In this sense, we used the SOLIDWORKS® application with the help of which, using the model of a truck, we studied its aerodynamic behaviour in a virtual tunnel. We considered that a frontal air flow with a speed of 25 m/s (90 km/h) acts on the vehicle. The variation of the air speed in the direction of travel of the vehicle was determined. The obtained results were presented in the form of flow trajectories and in the form of sections corresponding to the reference planes. We also determined the variation of vorticity, as a quantity specific to fluid mechanics in order to highlight the intensity of circulation or the speed of air rotation, from the rear area of the vehicle. [ABSTRACT FROM AUTHOR]

Failure of a rock mass happens when its shear resistance is exceeded. From a mathematical point of view, the failure condition is expressed by a relationship between the normal stress s and the shear stress t. In the paper, a virtual rock shear test device was built with in SOLIDWORKS, based on the characteristics of the press and shear plates with various inclinations from the Rock Mechanics Laboratory of the University of Petroşani. Considering that the upper plate of the press is fixed, and the lower one moves at a constant speed, we determined by numerical and analytical methods the shearing speed for various angles of inclination of the plates. [ABSTRACT FROM AUTHOR]

This paper deals with the issue of the service life of the boom of a bucket wheel excavator (BWE) in a lignite open-pit, solved through a fatigue analysis with the aid of the SolidWorks application. To this purpose, the boom of the excavator, which is a spatial structure of a truss type, has been modelled in compliance with the geometrical and material conditions of the real system. For the beginning the linear dynamic time response was determined for a load produced by the excavation forces, with a global damping of 2%. The results of the analysis allowed for the determination of the deformations which occur and their frequency. Then the model underwent a static strain analysis with the established deformations to determine the stress generated by the excavation process, whose results cause the events which produce the fatigue. The frequency of the oscillations (vibrations) corroborated with the estimated or actual number of hours of service within a year determines the number of events that cause fatigue. Proceeding from these, the analysis of the fatigue status corresponding to a period of excavation of 10 to 30 years has been determined. Making the fatigue calculations with the aid of the SolidWorks application, it is possible to evaluate the degree of damage according to the period of exploitation, which determines the remaining service life of the BWE boom. [ABSTRACT FROM AUTHOR]

The control of the functioning of the continuous transport system also implies the knowledge of the technological process by monitoring the flow of transported material. In this aspect, one of the classical methods used is weighing the material, which due to the limited reliability, has not been generalized. The paper proposes a solution to this problem by using an unconventional methods, that ensure reliability, accuracy and the possibility of integration in the general monitoring system. Permanent measurement, at equal time intervals, of the cross-section of the material carried by the conveyor belts and the instantaneous transport speed, leads to the determination of the volume transported. Based on the average density of transported material, the capacity of the continuous transport system can be determined. [ABSTRACT FROM AUTHOR]

Drilling is a highly demanding machining process due to complex variables like tool geometry, material failure and drilling fluid behaviour. In order to increase the quality of this process, a model was developed using SolidWorks, in order to simulate the behaviour of the drilling fluid flow for different speed and pressure values, from the point of view of the transport of debris out of the wellbore, prevention of external fluid influx, and the maintenance of wellbore stability. The results of the simulations demonstrate the effects of drilling fluid flow parameters on drilling and also confirms the capabilities and advantages of FEM simulation of the drilling process. [ABSTRACT FROM AUTHOR]

The pedestrian throw distance in the event of a frontal collision with a motor vehicle is of utmost importance, as vehicle speed at the moment of impact can be determined. This is a kind of analysis that is many times required and performed within the technical, judicial or extra-judicial technical expertise, in the case of road accidents involving pedestrians. The result of these expertise is particularly important both from the point of view of the criminal investigation, thus being able to establish guilt from legal point of view, as well as from the point of view of civil legal claims, as victims may seek compensation if the driver of the vehicle has violated the speed restrictions set for the road sector in which the accident occurred. In the paper a comparison is made between the results obtained based on equations used in specific literature and the results of the simulations performed in the specialized software called Virtual Crash. [ABSTRACT FROM AUTHOR]

For BWEs, the digging process is influenced by the forces opposing the working elements and cutting tools. These forces determine both the choice of the operating method and the choice of machines and their parameters. The value of the resistance forces can be calculated or determined by experimental methods so that the parameters and positioning of the cutting tools during the excavation process are appropriate to the magnitude of these forces. Studies conducted on failure causes of the mechanical parts show that the cutting and loading systems are causing the highest rate of failure, about 32% of all recorded mechanical failures. In the paper we will use FEM to analyze the deformations and stresses acting on the cutting tooth mounted on the rotor of BWEs. For this, SolidWorks® software was used, both as CAD tool to design the tooth as well as for modeling and simulation of the phenomena. [ABSTRACT FROM AUTHOR]

The value of the resultant forces acting on the BWEs cutting-teeth can be determined by calculation or by experimental methods so that the parameters of the working organs and their position during the exploitation process are appropriate to the magnitude of these forces. The deformations and stresses of the cutting-tooth during the excavation process is influenced by its position relative to the working organ (excavator bucket), which is determined by the cutting-tooth fitting mode. In this paper we will analyze the deformations and the stresses in the situation of the currently used cutting-tooth holder and propose another type of holder for which we will do the same determinations. The stress and deformation analysis was performed using SolidWorks® software. [ABSTRACT FROM AUTHOR]

Hoisting machineries have an operational duty characterised by cyclic nature and variable load intermittence. In order to determine the actuation power, there is considered a constant load duty that causes the same energetic effect during in the same time interval. Knowing the force values for every' tachogram stage allows for determination of actual force and, implicitly, actual power. The actual power value is the measure that imposes the power choice for the actuation engine. Starting from the variation of the accelerations corresponding to a certain actuation mode and using Solid Works® software program, the present study will present a method for determining forces and power within tachograms range. Moreover, classic scenarios will be presented, corresponding to actuation using asynchronous and direct current engines, by means of both analytical and numerical methods. [ABSTRACT FROM AUTHOR]

The present study introduces a method for simulation and modelling of statically balanced multi-rope hoisting machinery to the purpose of studying variation according to the hoisting stage of forces and powers at the periphery of the driving wheel. SolidWorks® software was used in order to achieve such purpose. The components of the technical system (driving wheel, hoisting containers, traction and balancing cables) were built and then assembled into a virtual system Geometrical and mechanical connections were applied upon the created assembly. By means of using the calculation facilities of SolidWorks® software and imposing the acceleration of the actuation engine, variation diagrams were drawn for acceleration, speed and forces at the periphery of the driving wheel, as well as for power according to hoisting stages. The scenarios of actuating hoisting machineries using asynchronous or direct current engines were studied. [ABSTRACT FROM AUTHOR]

Strength is the property of rocks to keep their internal structure unmodified and not deform under the action of a stress. Tensile strength is defined as the maximum tensile stress the rock can endure until its failure and it is usually lower than compressive and shear resistance. The paper presents the simulation of the indirect Brazilian Tensile Strength (BTS) laboratory test for a lignite sample using Geotechnica Irazu software and the Finite-Discrete Element Method - FDEM. [ABSTRACT FROM AUTHOR]

The property of rocks to oppose and keep their shape almost unchanged under the action of load is called strength. Compressive strength is defined as the maximum stress a material can withstand until its failure. Besides the physical characteristics of the rock, this is determined by factors such as orientation, duration and direction of the stress acting on the rock. This paper presents the simulation of a conventional Unconfined Compressive Strength (UCS) laboratory testing of a sample, with the help of Geotechnica Irazu software, based on the Finite-Discrete Element Method - FDEM. [ABSTRACT FROM AUTHOR]

An essential element when establishing the balance of a bucket wheel excavator is the determination of the barycentre, the best results being thus obtained by weighting after having installed all the components. The lack of correct balance for bucket wheel excavators determines their operation in an inadequate dynamic mode, or in extreme cases, there is the danger of losing stability by tilting over the excavator respectively suffering huge material and human loss. It is compulsory to verify for the correctness of the position and mass value of balance because there might be substantial error sources leading to compromise the operation. One of the most popular methods is that of weighting the entire equipment from the superior platform of the excavator. The weighting process implies the lifting of the excavators in three spots with hydraulic cylinders, the measurement of the forces, as well as the measurement of pressure reside the cylinders and of the stroke of each cylinder. The data measurement and rehashing installation is destined to determine the dimensions that finally define the weighting process of excavators or other operating machineries to which the balancing and control of stability is imposed. [ABSTRACT FROM AUTHOR]