Florin Dumitru Popescu

• Professor PhD
• University of Petroșani

Open-pit mining generates significant amounts of waste material, leading to the formation of large waste dumps that pose environmental risks such as land degradation and potential slope failures. The paper presents a stability analysis of waste dump slopes in open-pit mining, focusing on the Motru coalfield in Romania. To assess the stability of th...

Microwave treatment is one of the research topics to solve cutting problems of hard rocks such as low cutting rate and high tool wear. Microwave irradiation creates fractures in the rock body and decreases its strength. Numerous studies have been conducted to ascertain how microwaves affect the strength of rocks. Ten carbonate rocks are examined in...

Electrical contacts are important circuit components with diverse industrial applications, and their failure can lead to multiple unwanted effects. Hence, the behavior of electrical contacts is a widely studied topic in the scientific literature based on various approaches, tools, and techniques. The present study proposes a new approach to numeric...

Electrical contacts are important circuit components with diverse industrial applications, and their failure can lead to multiple unwanted effects. Hence, the behavior of electrical contacts is a widely studied topic in scientific literature based on various approaches, tools, and techniques. The present study proposes a numerical modeling and simu...

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...

Thermostats operate alongside intelligent home automation systems for ensuring both the comfort of the occupants as well as the responsible use of energy. The effectiveness of such solutions relies on the ability of the adopted control methodology to respond to changes in the surrounding environment. In this regard, process disturbances such as sev...

In this study, the fatigue usage factors for Findley and Matake stress-based criteria were determined in the case of an MK5×2 mine hoist drum brake system subjected to cyclic maneuver braking. The study was conducted for this type of brake system, because the majority of mine hoists in Romanian mines are equipped with this brake type, being in oper...

The paper studies the effects of a damping device linking the seat of the operator to the cabin floor of an operating bucket-wheel (BW) excavator. The effects of vibrations on humans were briefly presented first, based on a relevant literature review. Next, to a previously developed and validated model of the BW arm, a cabin model was attached, and...

This paper studies both the thermal and mechanical behavior of brake system models in the case of the emergency braking of a mine hoist model. Using a step-by-step approach inspired by studies conducted on small brake systems with high rotation speeds specific to road and rail vehicles, a comparative analysis using a computer simulation was perform...

Breakdown of stackers and excavators in opencast mines is possible because of operating, manufacturing and structural causes, and it produces high financial losses. These can be prevented by using various measures, including analyses and strength tests, with computerized modeling and simulation using FEA or other techniques being implemented in the...

The paper presents the state-of-the-art on the microwave assisted mechanical rock cutting by presenting actual findings and tendencies in the field in international literature, and the activities performed during the intermediate stage and the results obtained by the team from the University of Petroşani as partner within the ERAMIN-ERANET-MIWACUT...

This paper presents an investigation of the temperature variation of the two most important components of the braking system of a mine hoist, the disk and the pads respectively. Based on the complete model of the brake system created at 1:1 scale in SolidWorks, by taking into consideration only the disk, it’s mounting surface and the brake pads, th...

Starting from the general principles of material cutting, with applicability to coal and overburden excavation using bucket wheel excavators (BWEs), this paper proposes another method for calculating the drive power of the bucket wheel excavator by computer modeling. This approach required two steps. In the first step, the volume of the excavated m...

The sustainable exploitation of raw materials, with improved safety and increased productivity, is closely linked to the development of mechanical mining installations. Mine hoists are designed for the transport of material, equipment and personnel between the mine surface and the underground. The mine hoist braking system is of paramount importanc...

The paper deals with the modal analysis and frequency response analysis of a bucket wheel excavator (BWE) boom, obtained by simulation, based on a virtual model of an existing BWE boom. The boom, which generally is realized as a spatial truss, is the most vulnerable subsystem of the BWE, being submitted to severe operational loads characterized by...

For the ERc 1400-30/7 type bucket wheel excavator (BWE) used in various Romanian open pit mines, a virtual model of the boom was constructed in SolidWorks. On this model, the variable in time forces acting during the excavation process were simulated, and the time history analysis (time response) was performed. This dynamic time response analysis w...

The sustainability of lignite production requires, among other factors, cost reduction, high efficiency, as well as the increase of the production capacity. In order to rationalize and increase the efficiency of lignite mines, the optimization of the production process is necessary. In this respect, equipment revitalization and modernization is a k...

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...

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...

The specific energy consumption is mainly influenced by kinematics and dynamic measures of vertical transport installations aswellas by the compatibility of different composing parts and their subcompon The optimisation of kinematics and dynamic param characterising at ransport cycle is decisive considering the energy consumption. Also considring t...

Main pipe flow control of petroleum products transport systems represent an important problem on which the efficient operation of the system depends considering the process imposed requirements respectively the final consumer. As more precise flow control is, realized with a sufficient reaction speed, as more enhanced the energetic parameters and e...

The development of new petroleum products main pipe transport installations, in order to find the optimum choice concerning their architecture and structure, supposes the modeling and simulation of the considered system. Simulation allows the generation, evaluation of instances and establishes the best solution based on performance indicators which...

The operation of vertical transport installations are based on cable systems with electrical adjustable operation, which ensures the technical conditions regarding time variation in speed, the current in the main actuation engines and the acceleration during start-up and breaking. The actuation electrical systems are part of the category of the fas...

The operation of vertical transport installations are based on cable systems with electrical adjustable operation, which ensures the technical conditions regarding time variation in speed, the current in the main actuation engines and the acceleration during start-up and breaking. The actuation electrical systems are part of the category of the fas...

The study sets off the relation between the reliability of an electric drive system and the specific consumption of energy through the efficiency function used as a quantizing analytical element for the medium energy consumption throughout the safe functioning period of the system. The stability moments of the system as well as the collapse moments...

The purpose of this paper is to present a new method for the analysis of the stability of the slopes in open pits when the slide surface is plan or may be approximated by a plan surface. This is why for section works, the used term is breaking curve or falling curve. The stability of the mining works is a major problem, studied because of its techn...

Reliability has recently emerged from the quality concept. If quality represents the total of a product's qualities, which make it good for use according to the destination, the reliability represents the capacity of the product to maintain its quality during the entire usage time. Reliability is the quality of the product extended through time. An...

Reliability has recently emerged from the quality concept. If quality represents the total of a product's qualities, which make it good for use according to the destination, the reliability represents the capacity of the product to maintain its quality during the entire usage time. Reliability is the quality of the product extended through time. Re...

The study sets off the relation between the reliability of an electric drive system and the specific consumption of energy through the efficiency function used as a quantizing analytical element for the medium energy consumption throughout the safe functioning period of the system. The stability moments of the system as well as the collapse moments...

The paper presents a short survey of some topics related to speed control of electrical drives based on fuzzy PI controllers. In the beginning the conventional control systems of the main three motors mostly used in practice: DC motors, induction motors ...

The problem, on which emphasis is laid, is how to maintain the stability and equilibrium of bucket wheel excavators or any other extraction machinery during operation, the main machinery of a technological extracting system employed for coal mining. The balance survey, respectively that of the stability of these machineries is compulsory because th...

For the machineries and installations that have a small bearing surface compared to their height, an efficient control of balance can be done only if the angle of tilt of the superstructure is known, and if the angle does not exceed certain values. The limit values of the angle of tilt are determined by one condition, i.e. the composite force of bo...

The main problem, on which emphasis is laid, is how to maintain the stability of rotor excavators, the main machinery of a technological extracting system employed for coal mining, or any other extraction machinery, in balance. The balance survey, respectively that of the stability of these machineries is compulsory because the bearing surface is r...

Mining transportation is an important element of the economic efficiency rising in mining sector, because the transportation average included in the cost of production for one tone of extracted coal, represents approximately half of it. In order to control the transportation system and to have enough information about the below-ground and the above...

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 problem, on which emphasis is laid, is how to maintain the stability and equilibrium of bucket wheel excavators or any other extractio...

The main problem, on which emphasis is laid, is how to maintain the stability of rotor excavators, the main machinery of a technological extracting system employed for coal mining, or any other extraction machinery, in balance. The balance survey, respectively that of the stability of these machineries is compulsory because the bearing surface is r...

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, the...

The permanent measurement of the mining material volume controlled by continuous transporting equipment machines implies knowing its transversal section profile at a given moment and the instantaneous velocity of the transporting belt conveyor. The approximation of the material profile section is done by measuring the level of the transporting mate...