Scientific substantiation of the technology of explosive demand of gold-bearing quartzite
Вантажиться...
Дата
2026
Автори
Науковий керівник
Назва журналу
Номер ISSN
Назва тому
Видавець
Igor Sikorsky Kyiv Polytechnic Institute
Анотація
SHUKURLU E. Scientific substantiation of the technology of explosive demand of gold-bearing quartzite. – Qualification scientific work as a manuscript. Dissertation for the degree of Doctor of Philosophy in Specialty 184 “Mining” (18 - Production and Technologies). — National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, 2026.
In the dissertation, a new solution to an urgent scientific and technical problem is presented, namely the scientific substantiation of an improved technology for the explosive fragmentation of gold-bearing quartzites based on an enhanced composition of foam stemming, using mathematical modelling and geographic information systems to optimize the directions of mining operations. The current stage of development of the gold-mining industry in Azerbaijan is relatively new; however, it is already characterized by an active increase in production, expansion of the mineral resource base, and the opening of new open pits for the extraction of gold-bearing quartzite-containing rocks. Under such conditions, the application of modern geoinformation technologies becomes particularly relevant, as they make it possible to substantiate the directions of mining development, refine reserves, and optimize the volumes of rock mass extraction. At the same time, the significant volumes of gold-bearing rock mass fragmentation determine the need to improve the efficiency of drilling-and-blasting operations while ensuring the required particle-size distribution of the blasted rock. This is because the quality of fragmentation directly affects loading, transportation, and subsequent crushing processes, as well as overall production costs. Considering the possible consequences of blasting operations in open pits, one of the main technological tasks in the development of gold-bearing quartzites is to ensure the required fragmentation of the rock mass and to minimize the negative environmental impact. If blasting operations cannot be avoided, it is necessary to implement modern, scientifically substantiated organizational and technological measures aimed at achieving the required quality of rock mass fragmentation and reducing the environmental burden. In this dissertation, this task is solved by selecting an effective stemming material and conducting mathematical modelling aimed at evaluating the ejection time of the stemming from the borehole charge. Therefore, the research carried out in the dissertation and the obtained scientific and practical results are undoubtedly relevant. Chapter 1 substantiates the relevance of the study in the context of the strategic importance of gold deposit development for the mining industry of Azerbaijan. It is shown that increasing the efficiency and environmental safety of mining operations requires the use of modern tools for investigation and optimization of extraction processes, including the integration of geodetic monitoring with GIS technologies. Geodetic monitoring provides high-accuracy spatial data necessary for surface condition control, deposit parameterization, and analysis of changes within the mining area, whereas GIS technologies make it possible to integrate, process and interpret these data, build three-dimensional models, estimate mineral reserves, and forecast the consequences of mining operations. The dissertation develops a methodology for analyzing a gold deposit and assessing the prospectivity of mining direction based on geodetic monitoring and GIS, using the Tulallar deposit (Azerbaijan) as a case study and applying Surfer and Google Earth software tools. Chapter 2 examines the role of stemming as one of the key elements of the borehole charge structure, which determines the efficiency of explosive energy utilization. It is shown that reliable stemming ensures the retention of detonation products within the borehole during the critical stage of gas expansion, thereby increasing the initial pressure and the duration of the action of explosive gases on the rock mass. This contributes to the improvement of crack formation, displacement, and fragmentation of the rock mass, while also reducing unproductive energy losses into the atmosphere. It is substantiated that stemming performs not only the technological function of ensuring fragmentation quality but also prevents the premature release of gases from the borehole, which may lead to incomplete detonation, increased toxicity of post-blast gases, uncontrolled flyrock from the collar zone, and intensification of the air blast wave. In this regard, stemming should be considered an important factor not only in the efficiency of explosive rock breaking but also in the safety and environmental performance of drillingand-blasting operations. The chapter also establishes that the efficiency of stemming is determined not only by its length but also by its mechanical properties, structure, and geometry. The physical behavior of stemming during blasting is analyzed, including successive stages of shock compression, decompression, free movement, and ejection, which together determine the duration of borehole sealing and the time of pressure action on the surrounding rock mass. It is shown that optimal stemming should be technologically convenient to use and capable of delayed deformation under the action of expanding gases, thereby ensuring an extended retention time of detonation products. It is noted that traditional clay-sand mixtures remain a widely used solution due to their plasticity and adhesion; however, for short boreholes, improved stemming designs have significant potential. The presented analytical and numerical estimates confirm that even a slight increase in the retention time of detonation products can significantly improve blasting results, in particular by increasing fragmentation efficiency and reducing the specific consumption of explosive material. Special attention in the chapter is paid to the environmental aspect of stemming application. It is shown that, under open-pit mining conditions, the choice of stemming material significantly affects not only the particle-size distribution of the blasted rock mass but also the level of dust-and-gas emissions during mass blasting. In this regard, modern approaches to stemming improvement are focused on achieving two interrelated objectives: extending the retention time of detonation products to improve fragmentation and reducing dust-and-gas emissions through the use of materials capable of absorbing dust and neutralizing harmful gases. In this context, foam stemming is identified as a promising direction, as it ensures longer pressure retention, reduces the spread of the dust-and-gas cloud, improves muckpile characteristics, and may contribute to increasing the productivity of excavation and loading equipment. It is established that further improvement of foam stemming materials, including through the addition of 5% chalk, is a scientifically and practically justified direction for increasing the efficiency and environmental performance of blasting operations in open pits. In the third chapter, a numerical model of explosive loading in a gold-bearing quartzite massif was developed and implemented using the ANSYS Explicit Dynamics software package. As a result of the modeling, it was established that the decisive factor influencing the efficiency of explosive rock fragmentation is not so much the peak pressure value, but rather the duration of detonation product retention within the borehole. It was shown that, for both stemming variants, the maximum pressure of the detonation products is similar in magnitude; however, the subsequent pressure decay differs significantly. In the case of sand stemming, the pressure decreases much more rapidly, indicating earlier gas escape and the loss of part of the explosive energy. In contrast, in the case of foam stemming, a slower pressure decrease is observed, which means a longer preservation of the force effect on the borehole walls and the surrounding rock mass. An important scientific result of this chapter is the establishment of a polynomial relationship describing the variation of detonation product pressure over time for the two types of stemming. The obtained approximation made it possible to move from a qualitative analysis of the pressure curves to a quantitative assessment of the energy effect of the explosion. It was on the basis of these polynomial relationships that the average pressure values, the average forces exerted by the detonation products on the stemming, and the work of the detonation products along the stemming ejection path were determined. Thus, the polynomial approximation served not only as a tool for describing the dynamics of the process, but also as a basis for further engineering calculations characterizing the efficiency of explosive energy utilization. The quantitative assessment showed that the average pressure in the case of foam stemming is higher than that in the case of sand stemming and, accordingly, the average force exerted by the detonation products on the stemming is also greater. The calculations showed that the average force in the case of foam stemming increases by approximately 41% compared with sand stemming. This indicates that, when foam stemming is used, a significantly larger portion of the explosion energy is directed toward fragmentation of the rock mass rather than being lost due to premature gas escape from the borehole. The analysis of the stress state of the rock mass showed that foam stemming forms a more favorable stress distribution pattern. While in the case of sand stemming the explosive effect is concentrated mainly along the borehole axis, the use of foam stemming provides a wider and more uniform radial propagation of the affected zone. The effective area of stress distribution in the foam-stemming model is larger, which creates better conditions for uniform crack development and subsequent quartzite fragmentation. Chapter 4 summarizes the theoretical and applied aspects of controlling the quality of explosive rock fragmentation under open-pit mining conditions and substantiates the expediency of applying modern approaches to regulating the particle-size distribution of the blasted rock mass. It is shown that fragmentation quality is determined by the combined influence of geological and structural factors, in particular the physical and mechanical properties of rocks, fracturing, blockiness, and layering of the rock mass, as well as bench geometry, drilling parameters, charge design, initiation schemes, and unloading conditions. It has been established that, due to the multifactorial nature of the process, universal theoretical prediction of fragmentation without taking into account the actual heterogeneity of the rock mass and without verification based on the results of industrial or field blasts is limited. This confirms the need to combine calculation-based approaches with systematic monitoring of the actual results of drilling-and-blasting operations. It has been confirmed that the requirements for the quality of explosive fragmentation are determined primarily by the parameters of mining, haulage, and crushing-and-screening equipment, while the main evaluation criteria are the yield of oversized fractions, the average fragment size, and the uniformity of the particle-size distribution. Within the framework of this chapter, field studies were carried out on the use of foam stemming as an alternative to traditional sand stemming during the fragmentation of gold-bearing quartzites. A comparison of the two technological variants showed that the use of foam stemming provides a noticeable improvement in fragmentation performance. In particular, it was established that when foam stemming was used, the yield of oversized fractions decreased to 5%, whereas when conventional sand stemming was used, this indicator was 9%. Thus, the application of foam stemming made it possible to reduce the percentage yield of oversized material by 4%, which confirms its higher technological efficiency compared with traditional sand stemming. To ensure the objectivity of the comparison, the chapter applied a methodology of digital photo analysis of the particle-size distribution using specialized software. Unlike traditional methods of visual assessment or manual measurement, digital photo analysis makes it possible to promptly obtain quantitative fragmentation characteristics, including the average fragment size, the proportion of oversized material, and distribution uniformity indicators, as well as to expand the sample by analyzing multiple photographs. Importantly, this methodology is suitable for field conditions, does not require interruption of the production process, and can be used to form a statistical database for further optimization of drilling-and-blasting parameters.
Опис
Ключові слова
drilling and blasting, borehole charge, stemming, sand stemming, foam stemming, detonation products, pressure dynamics, pressure retention, stress–strain state, rock fragmentation, particle size distribution (PSD), oversized fractions, numerical simulation, ANSYS Explicit Dynamics, WipFrag, буро-вибухові роботи, свердловинний заряд, забійка, піщана забійка, пінна забійка, продукти детонації, динаміка тиску, утримання тиску, напружено-деформований стан, подрібнення порід, гранулометричний склад, негабаритні фракції, чисельне моделювання
Бібліографічний опис
Shukurlu E. Scientific substantiation of the technology of explosive demand of gold-bearing quartzite : dissertation submitted for the Doctor of Philosophy degree : 184 Mining / Shukurlu Elnur. – Київ, 2026. – 152 p.