This paper presents an analysis of the influence of burden deviation from the designed one on the intensity of blasting vibrations through the use of laboratory and field examinations. By definition, the burden represents the shortest distance from the axis of an explosive column charge to the free surface. It should be measured along the entire hole length, although, in practice, it is often measured only on the bench surface as the shortest distance from the axis of the explosive column charge to the crest. The real surface of the bench slope (free face) can be very irregular and should be considered during every blast. The deviation of burden in the blast pattern represents a serious problem in the field during blasting operation. Burden deviation from the designed one can be greater or lesser, affecting the results of blasting through poor fragmentation and sometimes causes unwanted effects like increased blasting vibrations or fly rock. The influence of burden deviation on the intensity of blasting vibrations was tested on a laboratory model, where 8 mm diameter holes were drilled into blocks with certain dimensions. The small explosive charges placed in blastholes were initiated. The design burden was set at 30 mm, as the distance from blastholes to the free face of the blocks. Any deviation in distance greater than the designed burden was taken as a parameter for comparison. During each initiation, vibrations were measured using a seismic instrument at a distance of 150 mm from the borehole. At the same time, the free face in the front of the blastholes was photographed to create a detailed 3D model of the blasted surface of the blocks for each blasting. Each measurement is presented on a diagram and classified depending on the values of the burden in the cases where the value of the burden is equal to the designed one, as well as any deviation that is smaller or larger than 30 mm. A total of 55 tests were carried out. The results were analyzed, and the model of dependence of each burden deviation from the designed one on the intensity of blasting vibrations was established under laboratory conditions. To verify the model, the same experiments were also applied in the field. The basic parameter of the model, the coefficient K, which represents the ratio of peak particle velocity and the surfaces of the blasted material from laboratory and field testing, indicates that there is a connection between these values. The deviation of the coefficient K, obtained from laboratory and field measurements, was 5.5%.

The increased volume of construction works, which includes the construction of new residential and business buildings, hotels, garages, shopping centers, and similar, is increasingly common in urban areas. Such works are increasingly coming into contact with different types of problems during construction, as one of these problems we single out the appearance of solid rock mass during excavation at the construction sites of future buildings foreseen in the construction project. During the construction of facilities or part of the building, which includes the underground premises of a building, it is necessary to excavate the material on site, however, due to its physical and mechanical characteristics, it is not always possible to excavate this material with conventional machinery. The composition of the material that is removed is sometimes in the form of solid rock, and thus its excavation is more complicated, so other methods must be used: controlled blasting, application of expansive mortars, etc. This paper presents some of the possibilities of removing solid rock material for the purpose of smooth construction of buildings.

This paper presents the technological and structural design solution of a tunnel-shaped underpass constructed for the coal conveyor belt of a combined transport system, serving the Roof Exploitation Zone of the Gacko - Central Field open-pit coal mine. The underpass has a clear opening of 6.1 meters in width and 2.5 meters in height and is positioned at an azimuth of 140 degrees. It is integrated beneath a haul road intended for ultra-heavy-duty mining trucks, specifically BELAZ trucks with a payload capacity of 110 tonnes, used for overburden transport. The underpass is equipped with wing walls on all sides, to ensure structural stability and seamless integration with the surrounding terrain. The solution ensures uninterrupted operation of the conveyor system while maintaining the safety and functionality of the haul road for continuous mining operations.

In the name of a better and safer energy future, it is our responsibility to focus our knowledge and activities to save on imported liquid and gas fossil fuels, as well as coal on which energy security of Serbia is based. The rationalization in the use of available energy resources certainly positively affects economy and the environment of a country. This paper indicates motivations for the application of the underground coal gasification process, as well as surface gasification for Serbia. The goal is to burn less coal, while simultaneously utilizing more gas from the onsite underground coal gasification, or by gasification in various types of gas generators mounted on the surface. In both cases, from the obtained gas, CO2, NOx, and other harmful gases are extracted in scrubbers. This means that further gas combustion byproducts do not pollute the atmosphere in comparison with traditional coal combustion. In addition, complete underground coal gasification power requirements could be offset by the onsite solar photovoltaic power plant, which furthermore enhances environmental concerns of the overall coal utilization.

Changes and deviations from previously defined plans are not characteristic only of mining, but they are an integral part of daily functioning in various areas of human activity. The process of defining plans is based on the facts and information available at the time, which reflect the level of understanding of a particular problem at a given time. By developing the project and expanding the spectrum of influential factors, significant changes can occur that affect the previously defined solution. The impossibility of predicting all relevant factors, as well as the emergence of added information, is not necessarily the result of human error, but also the result of natural processes that take place in parallel with anthropogenic activities. This paper presents a concrete example of the implementation of an investment project of key importance for the functioning of the exploitation system, in which an unforeseen situation occurred during the relocation of the DTD system in the Gacko coal basin. The occurrence of spontaneous coal combustion in the part of the surface mine intended for moving the crusher and other vital objects required a re-analysis, comparison of several variants and selection of the best solution. In the case of a change compared to the previously selected solution, additional and increased costs may occur, but when making decisions, it must be borne in mind that the quality and longevity of stationery and key facilities are of greater importance than the financial aspect itself.