Browse

This paper reviews a developed technology of mining steeply dipping mineral occurrences by steeply inclined sublayers, taking into account spatial position of sublayers relative to ore shoot. Parameters of phase and steeply inclined sublayers, till reaching final open pit depth, have been justified during studies. An order of steeply inclined layers formation on frontal open pit edges is determined depending on location of mineral resources on footwall and hanging wall. A new method of reactivation of a non-operat...

The scientific paper deals with the multi-criterion optimization of the teeth that are used on the buckets of bucket wheel excavators. From past theory and practice, it is known that geometry of the tooth greatly influences the cutting parameters and the endurance and the strength of the tooth itself. The dependencies between the cutting forces, the penetrating forces, the specific energy on the rake angle and the relation between this last one and the robustness of the tooth are somewhat contradictory, so in the ...

One of the frequent problems that needs to be addressed when mining coal deposits is the presence in the working face of cohesive materials having high mechanical strength in relation to the average rock to be excavated. These are generally called пїЅhard formationsпїЅ or пїЅhard inclusionsпїЅ and are in the form of either continuous layers or boulders. This problem is of particular importance in Europe where lignite deposits are exploited in large opencast mines utilizing Bucket Wheel Excavators (BWEs) as the mai...

This paper presents results for a research of the possibility of applying the combined methods of mining in construction of the underground premises in coal mines in the Republic of Serbia. The purpose of this study is to process the application and effects of combined (standard) methods of a pit remises construction through coal with a goal to find new technology of construction which will result in more productive and rational ways of their building. This study includes the analysis of the construction of pit pr...

Healthy and safe working conditions underground, especially in areas with potentially explosive atmospheres depend mainly on the method of operation and management of the ventilation system. For underground extraction of coal are running a complex network mining vertical, horizontal and inclined role extraction, transportation and evacuation the surface. Associated system of mining works has the air network to ensure the oxygen necessary for workers, diluting explosive gases and toxic substances and preparations t...

The scientific paper proposed deals with the reliability analysis of the average usage time of the brake pads as components of the braking system of the industrial front-end loader and transporter machinery used in mining operations in Romania. The research was conducted at the request of several mining companies in Romania, that are using the front-end loader and transporter machinery in their daily operations. The study is based on the empirical information and the preliminary reliability results that were recor...

Non-electrical equipment has been used for over 150 years in industries in which likely to occur a potentially explosive atmospheres and a great deal of experience has been gained in the application of protective measures for reducing the risk of ignition of such atmospheres to an acceptably safety level. For using non-electrical equipment in potentially explosive atmospheres, it became necessary to produce ignition protection concept standards which clearly defined these protective measures and incorporated the e...

The paper deals with the theoretical and practical analysis of the influence that the cutting direction of the bucket wheel excavator has on the digging forces acting on the wheel. Usually, when the terrace cut technology is applied, the bucket wheel of the excavator cuts vertical chips where mainly the perpendicular to stratification digging method is predominant. All the laboratory trials - done on the test rig - were conducted mainly for this type of vertical chip cutting. In cases when the drop cut method is a...

Jiu Valley represents one of the most important areas for coal mining in Romania, thus industrial development has generated a high level of health and safety at work issues. At work places in mining industry, the staff of the woodworking workshops is exposed to various concentrations of dust, possibly leading, in time, to occupational illnesses. Thus, wood processed in mining unitsпїЅ workshops is utilized for temporary support of coal faces, wrapping underground mining, insulation dams, ventilation doors, etc. Th...

Evaluation of explosion-proof protected electrical equipment in scope of certification is extremely important considering the risk of explosion that has to be minimized in order to ensure life safety and health of workers and to prevent damaging of property and the environment, as well as free movement of goods when they meet the essential safety requirements at European level. The purpose of this paper is to present the tests carried out on the cable entries with type of protection increased safety and flameproof...

In the Czech Republic, the production of energy using fossil fuels - particularly coal - is still a major proportion of total production. The energy sector is and will remain one of the most important areas of the Czech economy, ensuring supply of electricity and heat to the population and industrial enterprises. In the power and heating plants is burned primarily domestic brown coal mined in opencast mines in the north-western part of the Czech Republic, namely, Usti Region. For combustion of biomass in the Czech...

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 excavated rock. In this paper we use a new methodology, based on reliable laboratory data, which make possible to obtain correlation and regression formulas in order to pred...

The use of pneumatic energy in industry as well as in the tertiary system is quite frequent representing 10% of the industrial electricity consumption in the European Union, the life span of compressors being relatively long, namely between 14 and 16 years depending on the installed power. Although the compressed air demand of a coal mine is covered by performant compressors manufactured by well-known producers there still are multiple possibilities to increase their energetic efficiency. The working method is con...

The specific energy consumption is mainly influenced by kinematics and dynamic measures of vertical transport installations as well as by the compatibility of different composing parts and their subcomponents. The optimisation of kinematics and dynamic parameters characterising a transport cycle is decisive considering the energy consumption. Also considering the operation of the vertical transport installations, as well as the character of the variation of kinematics and dynamic parameters during a race, it has b...

The technology of cutting with a plasma arc is today a very advanced solution for thermally cuttable conductive materials. Plasma or also the plasma arc is composed of positively and negatively charged particles, excited and neutral atoms and molecules. As it contains free particles, it is electrically conductive and thus subject to the effects of an electric and magnetic field. This article discusses the use of plasma cutting technology on a CNC machine. The resulting quality of the plasma cutting is determined b...

The open pit Veliki Krivelj is a copper mine which operates within RTB Bor Group in Serbia. In 1998 a combined haulage system involving the initial dump truck haulage, crusher, belt conveyor and a boom spreader for waste disposal was designed and installed in order to reduce the costs on overburden removal. The designed productivity of the system is 4 700 t/h and it will be fully operational in the next few weeks. Up to date it has been capable of achieving maximal 50% of this productivity because only one of two ...

Efficient protection and construction of engine ering and other struct ures in seismically active areas is a series of contradictions, where an optimum solution must be found, which does not comprise a compromise at the expense of safety and security of the people, and which minimizes damage of property. Along with the increase of the needs for energy, the need for open pit mining production increases, which is related to the mass blasting with incr easing quantities of explosive, and nearing to the population cen...

The difficulty in reclamation of the North Bohemian Basin dumps consists in extremely severe properties of rocks in most of the dumps. It mainly concerns the rocks of the overlaying formation and the formation of brown coal seams. Sands, kaolinitic clayey sands and kaolinitic and illitic clays are the main materials bulk to the dumps. The admixtures of the bulk rocks consist of organic coal, siderite and pyrite. These rocks are mechanically unstable against wind and water erosion and they have obtained adverse, ac...

The process of truck shovel assignment for optimization of the transport systems in open pit mining is performed using software models and algorithms. With the aid of the software and hardware mechanisms, great steps can be taken in intelligent assignment and control of truck shovel systems. In this paper, open pit mining transport system has been modeled based on TSP modeling. Using genetic algorithms, the optimized travelling path for trucks has been obtained. The software has the capability of compound modeling...

The truck and shovel transportation system is the most important part of the open pit mining operation because a considerable amount of the total mining costs is related to it. Reducing the transportation cost has a great impact on reduction of the total cost. One method to reduce the cost per ton in transportation systems is the optimization of the truck–shovel assignment. In this paper, software has been developed for optimal assignment of N trucks to M shovels with different grades of the minerals, based on m...

The demands existing at the European Union level impose a new approach of the problems concerning the mining exploitation from the point of view of the effects and pressure exerted by them over the environment and of all the consequences of the socioeconomic development. Starting from the strategic objectives imposed by the European programmes at the environment-protection level, corroborated with the rather slow rhythm of reform of the Romanian mining industry determined by the delay concerning the achievement, i...

There are two methods fixed and real-time assignment for improving the performance of transportation through truck- shovel system in open pit mines. The real-time assignment (RTA) method is a better manner for optimization process of transportation system in open pit mines, especially in the complex transportation systems. The most significant objective of the RTA method is, introducing a transportation system which cause to increasing production per time and decreasing cost per ton. In this study, a software base...

In current paper the purposes of an environmental assessment are described and the method, through which the “Impacting Factors” and “Environmental Components” are determined, is also outlined. Then, according to the definition, possible scenarios, and matrixes of weighting factors, the algorithm which shows the relation between Impacting Factors and Environmental Components is determined. Furthermore, the derivation of matrixes and the method of environmental assessment are described. In order to compare ...

In this paper a combined (hybrid) model of fix and flexible with its software were presented. In the model, initially the trucks assignment operation using the fix approach was done and in the end of trucks operation cycle in the flexible method, trucks dispatching method was started. Results of fix assignment method implementation in each transportation scheduling period were used in the mentioned software and finally the fitness and most suitable shovel and truck combined system for the real-time assignment was ...

The "Propast - Dobrovolec" Mine produces bentonite clay by open pit mine technology. This report presents mining and geology characteristic of the field. Here are given the results from the determination of the physical and mechanical indexes of clay and rocks. The slope angles of the benches are determined by the combined schemes of V. Felenius, and for the general pit edged angles are used Prof.Fisenko’s methods (VNIMI - Sankt Peterburg).