Current gob filling devices are mostly bottom-dump scraper conveyors. Due to the structural characteristics of the scraper, the scraper-type Backfilling Slinger has high working noise, high energy consumption, and low conveying efficiency. In response to the above issues, this paper proposes the structural design of a belt-type gob Backfilling Slinger and suggests using a single-sided plow-type unloader for unloading. This paper models the unloading process mathematically, providing two types of unloading models: one that follows the angle of repose for stacking and the other that spreads evenly in the middle section. Subsequently, an experimental platform is used for unloading experiments to verify the correctness of the model. Finally, by comparing the casting performance of scraper-type and belt-type machines, it is found that, without considering the service life, the unloading capacity of the belt-type gob Backfilling Slinger has increased by about 75% compared to the scraper conveyor.
This study aims to develop an analytical method for calculating the parameters of destruction diagrams of cylindrical rock samples experiencing wedge-shaped fractures, facilitating the effective disintegration of rocks. The method employs analytical modeling to simulate the destruction process of cylindrical rock samples, leveraging experimental values of three key rock properties: shear resistance limit, internal friction coefficient and external friction coefficient. The proposed method accurately determines the limit and residual strength of the rock samples using these three indicators, which can be experimentally obtained through straightforward procedures in mining enterprises. This research marks the first instance of analytically modeling the destruction of cylindrical rock samples with wedge-shaped fractures while accounting for both internal and external friction. The practical application of this method allows for the rapid assessment of stress-strain parameters in rock samples, thereby enhancing the efficiency of rock disintegration processes in mining operations.
The study examines the impact of precipitation on the distribution of apparent specific electrical resistivity (rho a) in the soil through statistical analysis of data measured in a direct current geoelectric DipoleDipole (DPDP) electrode array in the park of the University of Miskolc, on an artificially constructed area. Following data filtering, regression analysis (Montgomery et al., 2012) and analysis of variance (ANOVA) (Montgomery, 2012; Kim, 2014) were applied to investigate the relationship between precipitation and rho a. Separate analyses were conducted for each measured depth level as a function of the precipitation amount recorded over the three months prior to the geoelectric measurements. The combined application of statistical methods provides an effective tool for understanding the hydrogeological state of the soil and the dynamics of subsurface water movement, while considering the influence of environmental factors and human activity. The results of the study may be valuable for interpreting data provided by monitoring systems and for shallow geophysical investigations aimed at mapping the hydrogeological functioning of an area.
The article discusses the dripstone structures in underground anthropogenic objects in the Sudety Mts. This region provides a good model area for studying dripstones due to the great diversity of the geological structure and the nature of underground facilities. The examined objects are primarily historical mines, but also military facilities and a pumped-storage power plant in the construction phase. Based on the recognition of 23 objects, the diversity of dripstones in this area is presented - their forms, the types of minerals that compose these deposits, and the environments in which they form. Atypical forms and dripstones not previously described in the literature have been characterized, such as: crystalline splash-cups, equivalents of cave balloons composed of iron oxides, conical stalactites formed by corrosion of steel elements in subaquatic conditions or forms called here stalagmitites. Based on these observations, comments are presented on terminology used to describe dripstones formed in different environments. The introduction of the terms hypogeothem and anthropothem is proposed.
The article presents a simulation model of a conventional and pipe conveyors created in the Tecnomatix Plant Simulation environment. The main objective was to analyse the normal forces, throughput, and energy consumption of both types of conveyors. The model allows for variable input parameters and experimental comparisons. Four experiments were conducted as part of the research, changing the belt filling coefficient and the design characteristics of the idlers. The results showed that a conventional conveyor transports more material than a pipe conveyor with the same belt width. However, the higher productivity of the conventional conveyor is also associated with higher electricity consumption. Conversely, for the same amount of transported material, the conventional conveyor has slightly lower energy consumption compared to the pipe conveyor. The analysis also confirmed the stability of both systems during long-term simulation. The most significant impact on performance was the filling coefficient, which directly affected the amount of transported material. The results provide practical insights for optimising the design and operation of belt conveyors.
This study investigated the effect of temperature (15; 25; 35 degrees C) on the kinetics and flotation efficiency of hardA(ortho-coking) coal using a fixed dose of machine oil as a collector and alpha-terpineol as a frother. The results show that coal flotation occurs fastest and most efficiently at 15 degrees C, achieving a volatile fraction recovery of 77%. At 35 degrees C, the recovery of volatile parts was 66%, or 47% at 25 degrees C. At the same time, hard coal flotation at 15 degrees C was found to reach a recovery of 45% after just five minutes, almost four times faster than flotation at 25 degrees C.
Selecting an optimal mining method is a complex and critical decision in underground mining, influenced by multiple geological, technical, and economic parameters. This study introduces a novel framework that combines Hierarchical Clustering (HC) and Correspondence Analysis (CA) to enhance the selection process by evaluating the consistency and similarity among outcomes from both first-pass methods (UBC and Nicholas) and several multi-criteria decision-making (MCDM) techniques (including AHP, EDAS, PROMETHEE II, AHP-PROMETHEE, TOPSIS, and VIKOR). The proposed HC-CA approach identifies consistent conflicts among the considered mining methods and quantifies the agreement among the initial assumptions of the adopted selection procedures. A case study of a Pb-Zn deposit demonstrates that the framework can effectively detect consistent and co-occurring (i.e., conflicting) solutions, such as Cut-and-Fill Stoping, Shrinkage Stoping, and Sublevel Stoping. The results show that the adopted design criteria align more closely with the UBC selection method, compared to the Nicholas selection procedure for the considered deposit. Additionally, applying the HC-CA approach to the input matrices prior to applying the MCDM methods can yield different results, compared to subjecting the MCDM output scores to the proposed framework. This integrative approach extends traditional selection procedures and links them with commonly used MCDM methodologies and unsupervised machine learning methods by enabling flexible strategy development, with the inclusion of considering mixed-mining-method scenarios tailored to the deposit. Additionally, the approach offers improved decision support in early project stages by visualizing affinities among different assumptions and hence potentially mitigating biases during the following design stage.
Raw materials such as feldspar, kaolin and illitic clay are used in the preparation of ceramic porcelain tile compositions according to their specific properties. Such raw materials are ground in ball mills in order to reduce the particle size to a certain value determined according to the operating conditions. In this study, it was aimed to compare capacity, time and energy spent in the grinding process of porcelain tile composition by using alumina and silica grinding medium from an industrial perspective. In this context, firstly, the grinding properties of the raw materials were determined with porcelain ball mill and Bond mill, separately. Bond Work Index values of magnesite, clay, kaolin and feldspar were determined as 8.7, 7.9, 12.3 and 14.2 kWh/ton, respectively. Then industrial grinding of a porcelain body was executed with a discontinuous horizontal ball mill. The industrial grinding studies showed that porcelain body was ground at 480 and 720 min to reach 2% sieve residue for +45 mu m with alumina and silica ball, respectively, which resulted as 625 ton/h capacity difference. Lastly, the ground materials in alumina and silica medium were compared in terms of water absorption, shrinkage, color and SEM analysis after sintering in porcelain tile conditions.
Economic and social development are inextricably linked to commodities. The attractiveness of a given mining sector in a given country and its economic potential are reflected in the market values of specific mining companies. This study examines the economic potential of Ecuador's mining sector and assesses investment opportunities through intrinsic stock valuation. Recent political developments have created a favorable environment for large-scale foreign mining investment, attracting growing international interest. The study contributes to the existing literature by addressing a notable gap: the lack of quantitative assessments of Ecuador's mining sector and the absence of stock-level valuation analyses specific to this geographic and sectoral context. Using Dividend Discount Models (DDM), Earnings Models (EM), and Cash Flow Models (CFM), it evaluates companies operating in or investing in Ecuador, a country positioned along the Andean mineral belt-one of the world's richest geological zones. By applying established financial models, this research offers a structured approach for evaluating mining-related equity investments in emerging markets. The analysis identifies undervalued and overvalued stocks based on fundamental valuation metrics, with firms such as Dundee Precious Metals, Lundin Gold, and Anglo American demonstrating high investment potential, while BHP group and Silvercorp Metals appears overvalued. These findings are contextualized within broader commodity market dynamics, offering insights into risk-adjusted investment attractiveness.
The samples used for this study were granite and spodumene ore (2000 grams) (divided into four equal parts with 500 g), 500 g for chemical analysis, and granite (500 g) was separately used as reference ores from the Kenticha ore deposit. Each test ore was weighed at 2000 grams, and the reference ore was weighed at 500 grams, and all were ground in a lab ball mill under the same conditions. Size analysis of the feed to the ball mill and the output from the ball mill was performed on test ore and reference ore, with the results properly tabulated. The feed and discharge particle sizes for the samples into the ball mill were calculated using the Gaudian-Schumann formula to ensure an 80% passing rate. The work index for spodumene ore, as cited in the literature, is found in the range of 10.4–11.5 kWh/ton. In this study, the Modified Bond Index method was used to determine the work index of spodumene samples from kenticha ore using granite as a reference ore. The work index of the Kenticha spodumene ore was discovered to be 11.391 kWh/ton.
In response to the failure problem of the roadway support structure for the deep buried mine, the mechanical calculation model was established based on the stress state and the boundary conditions of the composed anchor rod under the large surrounding rock deformation, and the failure discrimination criterion was obtained. Then a structural analysis unit for rock-composed anchor was established using ANSYS simulation software, which intensively researched the single-point and local failure characteristics of anchor rods in gob-side entries, and the optimization measures of the composed anchor rods were proposed. The findings reveal that the higher preload could restrain the axial displacement of the anchor rod, leading to stress concentration, fracture, or loosening of anchor bolts or nuts by the insufficient rock deformation. In addition, the stress concentration and plastic deformation of pallet orifice are significant as the main pressure-bearing part. The increase in the surrounding rock deformation leads to an enhanced combined action of pressure and shear force between the steel strip and the pallet edge, which makes the steel strip prone to failure. Consequently, the optimization measures of reducing prestress and increasing the size of pallet and strip are proposed, which can effectively control the deformation of surrounding rock and reduce the stress concentration, plastic deformation and failure rate of composed anchor rod.
Great problem associated with the Polish underground mining is doing the mining operations at an increasing depth in difficult geological and mining conditions, among others, in the area of remnant impact. The problem with remnants and its effect on the rock mass behavior is an important issue in the Polish underground hard coal mines and copper mines. The main goal of the paper is to investigate how the different sizes of remnants affect the geomechanical situation in the mining field. Numerical simulations were conducted for the case study of a mining field with a room and pillar mining system, where undisturbed remnants 10, 20, 40, 60, 100, and 200 m in width, were left behind. Results of numerical analysis demonstrate that the size of remnant has a great influence on the stress distribution and rock mass stability in the mining field. As the width of the remnant decreases, the values of vertical stress sigma y both inside the remnants and in its surroundings increase and reach very high values for narrow remnants. In contrast to the vertical stress sigma(y), the strength factor S-f decreases as the width of the remnant decreases. Simulations show also that leaving a large remnant in the form of a stabilizing pillar, improves the stability of the roof in the mining field but for remnants with high widths an unstable zone might be formed in the roof layers above the edge of the remnant at the goaf side which may cause sudden fracturing and collapse of rigid roof layers on the edge of the remnant. The results achieve in this paper can be utilized to enhance the safety and efficiency of underground mining.
The ongoing energy crisis highlights the urgent need to utilize coal from existing power plants for electricity generation. The exploitation of geological coal reserves in the Sibovci mine is influenced by the terrain configuration, particularly the roof and floor layers of the coal seam. This paper presents a methodology for coal sampling in the field and laboratory analysis to determine calorific value, bulk density, and natural moisture content. These parameters are crucial for ensuring both geotechnical safety and environmental protection during coal extraction and transportation. The study involved collecting 172 samples from the open coal seam profile, from an elevation range of 550 m to 650 m, using a modified drilling device. The samples were analyzed to determine the average values, variance, and distribution of bulk density and natural moisture content. Additionally, correlation analysis was conducted between the two parameters. This research helps optimize the combustion and transportation process, reducing environmental impacts such as air, water, and soil pollution. Furthermore, the findings have been applied in designing excavation slopes, contributing to improved stability and safety during coal extraction in the Sibovci mine. The study also aids in minimizing the environmental footprint of coal exploitation, ensuring that it aligns with established standards for sustainable energy production.
The composition of water has a significant impact on the flotation. With the increasing salinity of process waters used at the Division of Concentrator Plant (KGHM Polska Miedz SA), it is necessary to investigate the effect of changes in water composition on the flotation of copper ore components from the Legnica-Glogow Copper Basin area (Poland). In this study, the effect of changing water salinity on the flotation efficiency of copper and organic carbon in sulfide copper ore from the Polkowice Concentrator Plant was investigated. In the study, water taken from the processing plant was used. The mineralization and chloride concentration were 54.5 g/L and 23.46 g/L, respectively. The salinity of the process water was changed by concentrating and diluting water (60, 80, 120, 140%), as well as by adding chloride ions (5 and 10 g/L). Based on the study, it was found that with the increase in mineralization, also the chloride ion content of the water is increased, worse flotation of copper carriers and organic carbon was observed at the cleaning flotation stage. Moreover, it was observed that the more the salinity of the process water is increased, the more the efficiency of the rougher flotation improves - while increasing this salinity, the content and loss of Cu in the tailings from this stage decrease. The obtained research results indicate the need to monitor the salinity level of process waters and their composition and perhaps, in the future, the need for modification in this area.
Celem badań była kontrola wpływu eksploatacji górniczej na strukturę jaskiń z wapienia krystalicznego, w sąsiedztwie kamieniołomu w południowej Polsce. Zakres prac obejmował analizę warunków geologicznych i geotechnicznych oraz bezpieczeństwa badanych jaskiń. Badania obejmowały zastosowanie badań sejsmicznych MASW w celu określenia pustek skalnych, parametrów geotechnicznych i stateczności zboczy. Dla wykonania aktualnych map terenu wykorzystano fotogrametrię lotniczą krótkiego zasięgu. Sejsmometry i szklane płytki zainstalowane w pobliżu i wewnątrz jaskiń pozwoliły na scharakteryzowanie parametrów parasejsmicznych, takich jak prędkość drgań, przyspieszenie, przemieszczenie i częstotliwość. Badanie MASW umożliwiło określenie propagacji fal powierzchniowych Vs i wytrzymałości wapieni do gł.20m. Badanie na długości 48 m ujawniło kilka stref o znacznie wyższych wartościach prędkości fali sejsmicznej oraz izolowaną owalną strefę krasową jaskini o niższych wartościach Vs wynoszących 70-90 m/s. Strefy prędkości Vs są bardzo zmienne, przy czym największa zmienność występuje na pierwszych 22 metrach badanego przekroju. Występująca tam strefa znacznie niższych wartości Vs pozwala na identyfikację jaskini w profilu sejsmicznym. Analiza stateczności zbocza, biorąc pod uwagę wyniki badań geofizycznych, wcześniejsze badania i obserwacje terenowe wskazuje, że skarpa jest stateczna. W drugiej części badań zmierzono wielkość drgań parasejsmicznych w funkcji wielkości ładunku i odległości. Przedstawione badania obejmowały również stworzenie modelu 3D kamieniołomu, w celu określenia parametrów robót strzałowych i zminimalizowania ich negatywnego wpływu na chronione jaskinie. Przedstawiono również metodykę monitorowania stanu zboczy skalnych w sąsiedztwie miejsc prowadzenia robót strzałowych. We wnioskach scharakteryzowano parametry geotechniczne i wyniki analizy stateczności zbocza kamieniołomu w bezpośrednim sąsiedztwie chronionych jaskiń. Możliwe było określenie bezpiecznego poziomu drgań sejsmicznych dla badanych jaskiń.
This study analyses the effect of hydrophobicity on the floatability of sulphur, silicon, fluorite and galena. Flotation was performed in a Hallimond tube in distilled water and in the presence of a frother (alpha-terpineol). The results confirm that all the analysed minerals showed floatability in distilled water, with a varying yield, depending on the contact angle and density of each mineral. The introduction of a frother significantly improved the flotation efficiency, mainly for sulphur, silicon and fluorite.
The object of research in the present article is the intensification of the fragmentation of massifs with hard inclusions, by means of dispersed and additional drilling, using cast boosters with cumulative lining. The article presents the obtained dependences of the change in the depth of destruction of solid inclusions, depending on the length of the cumulative jet, its density and the strength of the solid inclusion, which allow to develop a methodology for engineering calculation of the parameters of the drilling-explosive works and the sequence of initiating the charges. The use of cast boosters with a cumulative-funnel, located in the lower part of the borehole, allows, at the expense of managing the action of the blast energy on the lower layers of the blasted massif, to reduce the average size of the fragments by 7.9% and by 1.6 times the resulting oversized fractions.
Choosing the optimal location for building a new or renovating an existing mining warehouse is of great importance, especially when it comes to a company that has multiple mines in different locations and needs to build one main mining warehouse. Multi-criteria decision-making finds wide application in solving many problems in mining, such as selecting the location of a main mining warehouse. When multicriteria decision-making is applied to solve a problem, a larger number of criteria are taken into account that affect the alternatives differently, and the optimal alternative is chosen based on them. In this paper, a methodology for optimal selection of the location of the main mining warehouse will be developed using seven multi-criteria decision-making methods. After the problem has been solved using all seven methods, the resulting rankings will be compared and the optimal location of the main mining warehouse will be selected.
Knowledge about the service life of the splices before they are made is extremely valuable information for the users of belt conveyors because having additional technical data about the conveyor and the place of its installation makes it possible to forecast the working time of the joint. The results of calculations of the service life of joints of multiply textile conveyor belts are presented. The calculations were made using a computer program specially created for this purpose, which predicts the service life of the joints before they are made. The program was created due to the implementation of research grant No. PBS3/A2/17/2015 financed by the National Center for Research and Development (NCBiR). The simulation results were compared with the data showing the working time of the joint in actual conditions of its operation in an underground mine. Comparing the simulation results of failure-free operation of joints with accurate data on the operation time of joints in the analyzed mines, it was noticed that the joints could work longer. Depending on the mine, it was from 3 to 8 months. The simulation did not consider sudden phenomena that could occur during the belt and joint operation. It was assumed that the belt operated smoothly, did not run off the conveyor, did not rub against the conveyor structure, etc. Each such phenomenon shortens its working time. The simulation results also showed that the joint made by hot vulcanization is characterized by a longer working time than the one made by cold gluing.
