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Coal mining causes undesirable terrain subsidence due to caving in of the overlying rocks into the already excavated space. Subsidence deforms the terrain, damages structures on the surface and water flows, which results in the formation of inaccessible wetlands and swamps, and these areas need to be reclaimed. The problem of large flooded areas as a result of mining activities also concerns an area known as пїЅKozinecпїЅ, which is located between KarvinпїЅ and Doubrava in the Czech Republic. That territory has lo...

Since the beginning of deep mining for the acquisition of minerals or driving galleries, later tunnels, man has faced the problem connected with draining used and polluted air (the so-called mine air), and transport of fresh air to the workplace. Since time immemorial, mine air has influenced and prevented the work of miners and drifters, as well as of the mechanized technology. The most significant factors of air pollution include exhaust fumes of mechanisms used in the performance of work, blasting fumes and, ob...

According Act No. 157/2009 Coll., on mining waste management, the Czech Geological Survey carried out a project of the Operational Programme Environment in 2010пїЅ2012. The project was entitled пїЅInvestigation of closed and abandoned mining waste facilities posing a serious threat to the environment or human healthпїЅ. The aim was to create an inventory of hazardous mining waste facilities and to develop a methodology for their assessment. In the Czech Republic, 300 potentially hazardous mining waste sites were i...

This paperwork is based on the data emerged from a conducted research related to a moisture influence on ignition sensitivity of air-methane gas mixture. For the purpose of this demarche it were used method of signal processing approach as it is data filtering and mathematical transform of the experimental data. In the first part of the paper, it was presented the spark test apparatus used for the experimentation and the results of the experimental data obtained during the tests with mixture air-methane and moistu...

The balancing devices in cable tension, DEC's, linking the extraction vessel (SKIP) and cables binding devices, DLCпїЅs, and are designed to equalize the tension in cables of extraction plant (multicable). The paper presents a new solution design of the screw-nut mechanism of initial tension cable for the uniformity tension and horizontal positioning of the rocking mechanism. The extraction vessels cables are attached to those by means of binding devices and equipment. Binding devices and equipment should be safe ...

Hydraulic fracturing is a widely used in the hydrocarbon production industry to stimulate oil and gas flow from traditional and shale formations. This technique is one of the essential elements of borehole mining technologies and is designed for controlled impact on the rock mass during the development of solid, liquid and gaseous mineral resources. The creation of a system of traversing cracks in the rock mass that are parallel to each other is of great practical interest for many geotechnical issues such as impr...

The process of Underground Coal Gasification involves risks of uncontrolled/unpredictable course of the gasification process. To minimize the risks of contaminants leaking outside the georeactor zone in the event of emergency is of a significant importance when aiming to maintain safe course of the process. The article presents methods and measures aimed at reducing the risk. These methods are based on reduction of the impact of released gaseous contaminants generated during the process. In order to achieve it, a ...

Dust is one of the major hazards that affect workers in the mining industry. Currently, there are many technologies that help reduce the dust load on the miners. But looking at the statistics of professional and profession-related diseases, it can be seen that the incidence of diseases caused by various industrial aerosols is not reduced. This indicates that the existing methods are not sufficiently effective. It is not excluded that the very method of estimating the dust load on workers is not correct and needs t...

The problem of stress state evaluation is really actual for the underground structures been exploited for a long time. Stress and deformation monitoring give opportunity for hazard prevention and planning operation mode of the underground facility. One of the most common methods of deformation control is convergence measurement, but transformation of measured data into stress state of underground structures is quite difficult. A technique for stress state evaluation of underground structures on the base of the ana...

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 excavated materials are relatively homogenous, without intercalations with excessive cutting resistance, it is not difficult to conduct the technological process. I...

Schemes of mining and construction operations have been developed for inclined trenches on the open pit edge, where transport platforms and safety benches using the drilling and blasting method of rock mass preparation are located. The volume of mining operations is calculated taking into account the dislocation of a part of the open pit edge of the deep open pit mine for placement of loading points at the bottom of inclined workings. A new scheme of conducting mining operations implementing steeply inclined conve...

The worldwide development of studies concerning volcanic-related deposits caused renewed interest in epithermal mineralizations in Sardinia and a prospecting program was developed in the eighties. A series of field surveys showed that hydrothermal alteration halos are widespread in the Tertiary volcanic terrains, and AuпїЅAg bearing mineralized outcrops were detected in a few localities. An exploration program was performed which reached the ore evaluation stage in two areas. The first economically viable gold dep...

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 first two models, the classical approach of shield mechanics, the loading scheme was modified by taking into account the horizontal force acting between the roof and th...

The authors propose a method for automated processing of seismic data obtained in high-stress rock masses structured as hierarchy of blocks with a view to detecting seismically active zones and seismic event clusters within a mine field. The processing algorithm is developed based on the statistical theory of classification and cluster analysis. Suitable for zoning of seismic data, FOREL family algorithms include algorithms based on the idea of incorporating objects in the zones of their highest concentration into...

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...