Iosif Andras

• PhD
• Professor (Full) at University of Petroșani

The innovative development of the fossil mineral resource exploitation industry requires the existence of well-trained specialists both theoretically and practically. It is mandatory today for an engineer - whatever his technical specialty is - to have important digital knowledge in addition to the knowledge strictly related to his specialization....

Mining machinery and equipment have changed little in recent decades, from the point of view of the principle of operation, construction and structure. But in terms of dimensions, performance and stresses they have made a lot of progress, experiencing unprecedented sophistication and complexity. In order to fulfil the new requirements imposed by 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 paper deals with an overview of the state of art on using microwaves for assist hard rock cutting with mechanical means. The information provided consist on actual findings from the literature review, and the results of researches performed in this field by the team of the University of Petroșani. Tests have been carried out to determine the ph...

The bucket wheel excavators (BWE), when operating in faces with hard intrusions (rock structures with increased cutting resistance) are submitted to loads exceeding those arising during the operation in normal conditions. The most vulnerable structural element of the BWE from the point of view of these loads is the boom. The unexpected occurrence o...

The bucket wheel excavator (BWE) is a continuous working rock harvesting device which removes the rock by means of buckets armoured with teeth, mounted on the wheel and which transfers rock on a main hauling system (generally a belt conveyor). The wheel rotates in a vertical plane and swings in the horizontal plane and raised / descended in the ver...

The quality of bucket wheel excavators (BWEs) operations is largely influenced by the physical-mechanical (structure, mineralogical composition, plasticity, anisotropy, degree of fracturing etc.) and technological properties (compressive strength, tensile strength, shear strength, compaction, consolidation, cutting resistance etc.) of the rocks. If...

The paper deals with the study of Powered roof support analysis, taking into account the interaction with surrounding rocks. In this respect, an analytical model of kinematics and load of the shield, a differential model of the shield-rock system equivalent stiffness and a Fuzzy logic based analysis of the parameters variation are presented. In the...

The performances of the excavation machines depend largely on the tool and overall machine characteristics and on the other hand on physical mechanical characteristics of the excavated rock. There were more theories based on analytical deductions to explain the main cutting parameters on the basis of basic physical mechanical properties of the exca...

The paper shows the results of a lab model for strain gauges based measuring system for multiple measuring heads of the mechanical stress in lattice structures of the bucket wheel excavator for open pit mines-harsh environment. The system is designed around a microcontroller system. Because of specific working conditions, the measuring system sends...

The paper is a summarizing the validation stage of the strain gauges based remote measurements in bucket wheel lattice structures. The validation process is required when multiple and synchronized measurements are required in harsh environment. The authors propose virtual models with specific interaction facilities demanded in dynamic measurement s...

The proposed paper shows some experimental results of a research in metallic structures inspection by using a high definition camera controller by high processing capabilities. The dedicated ARM Cortex-M4 initializes the ARM Cortex-M0 system for image acquiring. Then, by programming options, we are action for patterns (abnormal situations like meta...

This study was conducted based on the considerations set out in the National Strategy for the Management of Sewage Sludge as well as in the Mining Law and Mining Industry Strategy (focusing on the obligation of ecological restoration of mining waste dumps). In the first part of the paper is briefly described the area where the studied objectives ar...

The mining production systems, both for underground and open pit extraction consist mainly in a string of equipment starting with the winning equipment (shearer loader, in case of underground longwall mining or bucket wheel excavator in case of open pit mining), hauling equipment (armored face conveyor in longwall mining or the on-board belt convey...

The future of coal mining in Jiu Valley is acutely conditioned by a multitude of factors, arising from the interference of force lines of different decision centres, the effects of which – often cumulative or even antagonistic – may lead to irreparable consequences. The failure to take into account the totality of all the economic, social-geographi...

The traditional design of mining machinery manages separately the structural and functional parts of the design object (mechanical, electrical, hydraulic and control units). The mechatronics, as a design philosophy may offer an innovative approach in the design of plant and equipment used in open-pit or underground mining. The multi-domain nature o...

Considering the specific features of the Transilvania salt mine ventilation system, the projected evolution of the mine workings network and the hazards related to the increased moisture content in air during the summer period, a three-years extended research study was carried, aiming at the global Ocna Dej salt mine’s ventilation system optimizati...

The inadequate comprehension of specific hazards, mainly related to their nature and magnitude, have lead in the past to the occurrence of several catastrophic events in the Romanian mining industry. The mining industry, like other major global industries, must consider and manage risks to business objectives, to remain successful. Management of ri...

The objective of mine closure is to prevent or minimize long-term environmental damage, and to create a self-sustaining natural ecosystem or other land use based on an agreed set of objectives. The Romanian mine closure legislation should be enforced in the coming years for taking best follow up actions and management of post mining closure. The mi...

This paper presents the power and energy characteristics with the view to defining and analyzing the working mode of the rotor excavators in operation at Jilt Sud and Jilt Nord lignite open casts, for lignite mining and for mining of the predominantly overburden rock, i.e. the sandy clay.

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 ...

This paper presents the power and energy characteristics whit the view to defining and analyzing the working mode of the rotor excavators in operation at Oltenia lignite open casts, for lignite mining and for mining of the predominantly overburden rock, i.e. the sandy clay. The forces which act on a bucket and wheel, the force needed for the excava...

The paper deals with a comparative assessment of the different variants of tunnel ventilation systems in case of strong (heavy) fires. The longitudinal, the transversal and combined ventilation systems are presented and analyzed. It is concluded that the most sure systems are the transversal and combined ones, because always exists separate channel...

The optimization of the coal winning process using different mechanical and alternative cutting techniques using appropried mathematical models is an up to date reserch methodology. In the paper, two kind of such models are presented, first using deterministic analytical relations evaluated by numerical calculus, and the second using Monte-Carlo si...

The paper deals with the outlining of the strategies for the future development of mining and energy sector in Romania, taking into account the relational balance between supply security and environment protection. The issues regarding the harmonization with EU legislation and the requirements of the concurrence driven market economz and globalizat...

The authors establish the value and position of the maximum lift and the connective forces between the elements of indigenous powered supports, taking into account, on the one hand, the ease of their selection, and on the other, their dimensioning.

The paper presents three alternatives for the graphical and analytical synthesis of the lemniscate mechanism of the powered roof support units. The first alternative uses the rod plane corresponding to its middle position; the second one uses Ball's point (of the longest inflexion) and the third one uses a particular case of degeneration into simpl...

A method is presented for the Synthesis of a Cam Profile for the Kibble Guiding Sledge to Open and Close the Safety Platform Doors of a Sinking Mine Shaft.

The authors presents the synthesis of the kibble guiding sledge cams used for the automatic opening and closing of the safety platform doors in the sinking mine shafts. The results are given for seven movement laws obtained on a computer for a practical example as well as a nomogram for graphical cam determination.

The present tendencies in glass industry are reduction of energy consumption in glass manufacturing, considering that the highest expenses are the energy used to reach the high temperatures in the furnace. The paper presents the research on the furnace work condition, with direct glass melting flow in SC STAR GLASS SA Tg. Jiu.

Taking into account the advantages of the rotating drilling versus the percussive one, it is necessary to manufacture removable drilling bits for rotating drilling in hard rocks. The actual level of the knowledge regarding the rock cutting does not allow an adequate mathematical description of the interaction between the tool and the rock in case o...

The paper shows the results that have been obtained during the elaboration of a main transportation system at Ocnele–Mari Salt Mine and who are going to replace the transportation by vehicles with a continuous -type transportation that uses belt conveyor.

This paper analyses the operating condition for the transportation system used in the National Hard Coal Company in Petrosani. This analysis is made for each mine apart and underlines the directions that have to be followed so as to achieve a well-structured revamping that is going to be efficient from an economic point of view. The study of the st...