Mining Conditions Research Articles

Regularities of subsidence progress in terms of the repeated earth’s surface undermining in the context of Lviv-Volyn coal basin

Study of deformation manifestation within the undermined rock formation and at the earth’s surface is among the key problems during underground mineral mining. The paper has analyzed the available methods identifying the earth’s surface subsidence in the process of its undermining through underground excavation. The analysis has shown branching as well as different approaches and numerous factors. The researchers believe they influence the results. Hence, the purpose is to substantiate regularities of the earth’s surface subsidence while its undermining by means of longwalls varying in their length. The study was carried out using materials of the actual observations on the subsidence in 31 profile lines under the conditions of SE Lvivvuhillia mines. To identify the functional regularities, the factors were assumed which researchers consider as the most influential ones. The performed correlation and regression analysis demonstrated clear relation only for longwall length and moderate relation between subsidence deviation and longwall length-mining depth ratio. A graphical-analytical technique was applied to define distribution of subsidence deviation points depending upon a longwall length-mining depth ratio; moreover, a coefficient was determined to be used while calculating design subsidence values if the longwall length-mining depth ratio is 0.1-0.7.

Prospects for systematization of lignite deposits to provide Ukraine with raw materials in the postwar period

The contribution of the mining industry to the economy of Ukraine and the current state of coal mining are analyzed on the basis of statistical data on balance sheet reserves of black coal by grade. The indicators of balance reserves and quality characteristics of lignite and associated minerals (coal clays) of the Dnipro Basin are specified. Prospects for the resumption of production are presented and a preliminary economic assessment of the attractiveness of the lignite application is made. The lignite reserves are partially recalculated taking into account the extraction of coal clays to increase the capacity of the country’s fuel and energy sector. The prospects for compiling a catalog of lignite raw materials are determined, taking into account the mining and geological conditions of occurrence and the quality characteristics of the mineral. The scientific novelty of the research is to catalog the deposits of the Dnipro Basin and rank them with a preliminary technical and economic assessment of lignite production. The practical significance is to create a ready catalog of lignite raw materials that will allow a potential investor to implement his or her economically viable project for the development of the deposit.

Monitoring and estimation of mining and geometric indicators of the deposit

The article presents the results of mining and geometric modeling of indicators of mineral deposits. In order to estimate and monitor them, a wide range of geoinformation systems-based methods and techniques of geometrization is applied. The sequence and stages of mining and geometric estimation of deposits are described considering specific mining and geological conditions. The built models are used at Ukraine’s mining enterprises that develop solid minerals. Much attention is paid to processing initial mining and geological data, providing the basis for mining and geometric modeling. Geostatistical methods give high results when processing and assessing reliability of the input modeling data and processing and presenting modeling results. Different types of deposits require different approaches to geometrization. Deposits with high variability of indicators require accounting, data grouping and zoning. For this purpose, a heuristic algorithm is developed, which is an efficient independent method of modeling and enables considering the high level of heterogeneity of the spatial distribution of mining and geological indicators of the deposit. The results of the modeling can be used for deposit estimation and monitoring, reserves calculation, and mining operations planning.

Parametric evolutions of explosive fracture zones in the explosion of series of blasthole charges with a complex structure

The purpose of the paper is to specify calculations of a rock mass fracture zone in the explosion of series of blasthole charges with a complex structure under mathematical modelling of their interaction if parts of the blasting agent are spaced along the well length by means of an inert material. The parts are blasted sequentially. Therefore, dynamic load of exploded rock mass has been analyzed depending upon a blasting order of the charges and their parts. Originality is to define more exactly the regularities of interaction between explosive energy of blasthole charges with the specific design and rock mass enclosing them. The developed methods help identify usability of the explosives, designed by the authors, and simplify calculations of drilling-and-blasting description. It has been proved that selection of charge mass with different ratios of their parts in the sequential wells, and variation in lag intervals between the explosions make it possible to control a process of rock mass loading depending upon the specific mining and geological conditions if features of a force field are known. The findings expand methodological basis as for design of open pits while favouring implementation of explosive charges which structure is proposed by the authors.

Improving the efficiency of gear grinding technology for mine conveyor drives

The aim of this work is to develop a mathematical model of the gear grinding process using the method of high-performance profile copying and determine the optimal parameters of grinding modes according to the temperature criterion. It is shown that in order to ensure defect-free machining of gears under deep grinding conditions, it is necessary to significantly reduce the rate of the feed speed of the grinding wheel along the tooth of the gear wheel. For a grinding depth of 0.4 mm, it should be equal to 2.27 m/min. In this case, the machining productivity can be increased up to 5 times with the simultaneous elimination of the formation of sticking, microcracks and other temperature defects on the machined gear surfaces. This processing effect is achieved by using a modern HOFLER RAPID 1250 gear grinding machine and highly porous abrasive wheels, which are characterized by high cutting capacity. Thanks to the improved quality of gear processing, the quality and performance of manufactured mine conveyor drives (planetary gearboxes with a power of more than 200 kW) have been improved, and the number of repairs required in harsh mine conditions has been significantly reduced.

A new method for layout layer optimization of long horizontal boreholes for gas extraction in overlying strata: A case study in Guhanshan coal mine, China

AbstractThe gases released by underground coal mining pose a threat to mine safety, lead to resource wastage, and contribute to environmental pollution. Employing long horizontal boreholes (LHB) for gas extraction proves to be an effective solution. However, accurately determining the LHB's position within the overlying rock strata is challenging due to complex mining and geological conditions. This study introduces a novel “zone‐position” method for identifying the optimal LHB placement, utilizing both physical simulation tests and theoretical analysis. The approach comprises two steps. Initially, it identifies the appropriate LHB layout zone within the overlying strata. It delineates four subzones within the fractured zone, among which the stable fractured subzone (SFSZ) is identified as the most favorable for LHB placement. The boundaries of the SFSZ are also defined. Subsequently, the method focuses on pinpointing the LHB's precise location within the SFSZ, proposing a criterion that considers gas accumulation, strata permeability, and LHB stability. Application of this method in engineering projects demonstrates that the gas extracted by LHBs accounts for about 60% of the total gas emission. Furthermore, the volume of gas extracted at the optimal LHB location reaches up to 5.52 m3 min−1, triple that of other locations.

Numerical Multifield Coupling Model of Stress Evolution and Gas Migration: Application of Disaster Prediction and Mining Sustainability Development

At present, coal mining is gradually shifting towards deep areas, and coal mines under deep mining conditions are more prone to coal and gas outburst accidents. In this research, we aim to explain the causes and mechanisms of dynamic disasters, which are caused by the combined action of static load, gas, and dynamic load on tectonic regions in complex stress field environments. Through numerical simulation using COMSOL Multiphysics software, based on the geological conditions of a mine in Jilin Province, it was found that faults lead to abnormal stress in tectonic regions. The combined action of dynamic and static loads results in excessive stress, causing the fragmentation and displacement of the coal body, leading to coal mine disasters, thus disrupting sustainability. Additionally, the coal matrix gas entering fractures raises the gas pressure and leads to the accumulation of methane near earthquake sources. Dynamic loads accelerate gas desorption in coal and increase porosity and permeability, facilitating rapid gas migration. This influx of gas into the roadways exceeds safety limits. Then, based on these findings and on-site conditions, a set of sustainable measures for coal mines has been proposed. This research offers theoretical guidance for enhancing safety, stability, and sustainability in coal mining processes.

Hydrodynamic processes in designing diamond drilling tools

Relevance. The rational choice of drilling tools is one of the components of a positive result of exploration, mining, drilling operations. The function of a complex solution of problems arising when drilling wells is assigned to a modern drilling tool. Today there is a great variety of designs of rock cutting drilling tools. However, scientific achievements in improving the material and technical production base contribute to the development of drilling technology and creation of new, more efficient tool designs. The most promising and effective in various mining conditions is a diamond drilling tool. During the operation of such a tool, flushing fluid circulation is of great importance, especially in the bottomhole zone of the well being constructed. When designing the structures of a diamond rock cutting tool, it is necessary to take into account not only the strength, cutting, and stabilizing properties, but also the possibility of an effective fluid flow in its circulation system, i.e. without flow energy consumption to overcome resistance, with sufficient capacity for cuttings removal and the necessary level of cooling, lubrication and implementation of other functions of the flushing fluid, which contribute to improving drilling results. At the same time, modern methods of designing a drilling tool should take into account the influence of the drilling fluid, its properties, and the nature of the flow on the rock destruction mechanism, i. e. require a thorough study of the nature of the fluid flow in the contact zone of the tool cutters with the rock. The article proposes the position of considering the design of a diamond drilling tool cutting surface from the point of view of the influence of hydrodynamic processes on the nature of cutters rock interaction. The results of the study of both the author herself and well-known world manufacturers of diamond drilling tools are given as arguments. Aim. To study the influence of the design features of the existing diamond drilling tool on the nature of the fluid flow in the bottomhole zone of the well during drilling. Objects. Designs of diamond drilling tools, hydrodynamic processes associated with drilling. Methods. Analytical method, computer simulation method. Results. Differences in fluid circulation in certain types of diamond drilling tools are determined. The zones of the diamond rock-cutting tool are distinguished. They differ in the nature of the fluid flow. Directions for reducing hydraulic resistance in the bottomhole zone of the well due to changes in the design features of the drilling tool were established.

The current state of the non-ore mineral deposits mining in the concept of the Ukraine reconstruction in the post-war period

AbstractThe study of quantitative and qualitative indicators of the non-metallic mineral deposits mining based on recognized methods of economic and technological assessment to determine the damages and the development of technical–technological measures for the providing the mining industry of construction and bulk materials from the crisis in the post-war period. To assess the state of non-ore mineral deposits, the authors of the article used the following research methods: critical analysis of literary sources, statistical processing of data on the mines functioning and the probability of their manifestation in specific mining and geological conditions. Based on the selected UNIDO method, which is used for the evaluation of high-budget projects, the quantitative performance indicators of the selected quarries of non-ore raw materials have been established. Systematization and visualization of the obtained results were carried out with the help of Excel calculation tables from the available software product MS Office. The main problems associated with the activity of mining enterprises that develop deposits of non-ore useful minerals are highlighted. Qualitative and quantitative values of the work of the selected mines have been prepared according to European standards, which serve as initial data for assessing the economic attractiveness and the possibility of their restructuring in the post-war period. A forecast of the development of the industry is provided on the example of individual technological units of entrepreneurial activity for the nearest period. Dependencies of changes in production capacity indicators of mining enterprises developing non-ore mineral deposits have been established. Data on the spatial distribution of reserves of construction and backfill materials (gravel, sand, clay) were studied. Using generally recognized international methods of assessing the efficiency of enterprises, changes in the priority of mine development were determined depending on the needs of the Ukrainian economy and the destruction of territories caused by military actions, that appeared due to the aggression of the RF. The effectiveness of the methodology was proposed and confirmed, which allows determining the operative parameters of mines, which are mining non-ore mineral deposits. It gives the possibility to assess the economic attractiveness of individual mines and subsequently predict the possibility of their restructuring for the introduction of the innovative equipment and technologies in accordance with generally recognized international standards.

Machine learning‐assisted wearable sensor array for comprehensive ammonia and nitrogen dioxide detection in wide relative humidity range

AbstractThe fast booming of wearable electronics provides great opportunities for intelligent gas detection with improved healthcare of mining workers, and a variety of gas sensors have been simultaneously developed. However, these sensing systems are always limited to single gas detection and are highly susceptible to the inference of ubiquitous moisture, resulting in less accuracy in the analysis of gas compositions in real mining conditions. To address these challenges, we propose a synergistic strategy based on sensor integration and machine learning algorithms to realize precise NH3 and NO2 gas detections under real mining conditions. A wearable sensing array based on the graphene and polyaniline composite is developed to largely enhance the sensitivity and selectivity under mixed gas conditions. Further introduction of backpropagation neural network (BP‐NN) and partial least squares (PLS) algorithms could improve the accuracy of gas identification and concentration prediction and settle the inference of moisture, realizing over 99% theoretical prediction level on NH3 and NO2 concentrations within a wide relative humidity range, showing great promise in real mining detection. As proof of concept, a wireless wearable bracelet, integrated with sensing arrays and machine‐learning algorithms, is developed for wireless real‐time warning of hazardous gases in mines under different humidity conditions.image

Lora Based Coal Mine Safety Monitoring and Security System Using Smart Helmet

The process of removing coal from the earth is called coal mining. Coal is used as fuel by the steel and cement industries to extract iron from iron ore and to make cement. The category that includes the underground mining business includes all factors that require routine monitoring, including methane gas, high temperatures, fire accidents, and so on. The safe production level of coal mines is still low, and frequent tragedies there result in significant losses of life and property. It is crucial to keep an eye on the working conditions in coal mines since the variety of work done there and the complexity of the mine environment are the main causes of disasters. The coal mine based on LoRa Long-Range Wide Area Network (LoRaWAN) technology is used by the Safety Monitoring and Security System to improve security and safety in coal mines. This system incorporates cutting-edge sensors to continuously monitor the surrounding environment, gas concentrations, and worker welfare. LoRa enables seamless communication and quick identification of potential risks because to its long range capabilities.

Комплексная оценка геоэкологических рисков при ведении открытых и подземных горных работ

Introduction. Geo-ecological risk is the probability of adverse events leading to a violation of the stability of the existing ecological system or the natural and technical geo-system “rock mass – technology – mining”, formed as a result of mining activities. The main elements of geo-ecological risk in mining are dangerous geological (landslides, rock collapses, suffusion-erosion processes, karst, etc.) and hydrogeological processes. The purpose of the research. Development of a method for integrated assessment and management of geo-ecological risks in open-pit and underground mining operations. Methodology. The paper calculates the geo-ecological risk in relation to each technological process. At the same time, the ranking of the possibility of a negative process in mining activities is determined on the basis of an expert approach, taking into account the specifics of mining and technological operations. Statistical data and expert assessments formed the basis for determining the quantitative values of geo-ecological risks in mining operations. Results and discussion. The obtained quantitative values of geo-ecological risks indicate that a management system is needed. The developed geo-ecological risk management system makes it possible to conduct a comprehensive assessment of them in the conditions of mining and mining and construction production and, based on forecast calculations, determine the distribution zones of the most dangerous processes in the “rock mass – technology – mining” system. Conclusion. Research has been conducted on the formation of a comprehensive assessment of geo-ecological risks, as well as their forecasting during open-pit and underground mining operations. It is determined that the geo-ecological risk in open-pit mining consists of the risk of alienation and degradation of soil, the risk of pollutants into the atmospheric air, the risk of pollution and depletion of the water basin, and in underground mining – from the risk of atmospheric pollution of the working area, the risk of changes in the groundwater regime and the risk of geo-mechanical transformations of the rock mass.

Снижение биокоррозии деталей оборудования, эксплуатируемого в подземных выработках за счет применения детонационного Ti-Cu напыления

Introduction. The wide distribution of microorganisms in the natural and technogenic environment, in the conditions of underground mine workings, is explained by their phenomenal adaptation capabilities. The high activity of microorganisms at significant depths under extreme conditions is due to the peculiarities of their metabolism. The maximum number of these factors is typical for underground mining. The lithosphere, in which underground structures are built to ensure the development of deposits, in addition to its well-known characteristics, is also a habitat for microorganisms. The waste products of these microorganisms significantly influence the rate of corrosion of metals. Often the scale and speed of bio damage are so significant. Therefore, the study of microbial bio damage processes and their prevention under these conditions is an extremely urgent task. Materials and methods. The corrosion rate in an aggressive biological environment of three types of samples was studied. The first type of samples were ordinary plates made of St 3. The second type of samples was the same St 3 but with antimicrobial enamel XC-5286 applied to the surface. And the third type of samples were samples made of St 3 with a detonation coating applied to their surface from a mixture of Ti (PTN-8VT10) and Cu (PMS-1) powders. These samples were exposed to a biologically active corrosive environment for one month. Then the level of damage and corrosion development on the surface of the samples was measured. Results. The results of the study showed that the use of the method of detonation thermal spraying makes it possible to form a protective Ti-Cu composite coating with anti-corrosion properties on the surface of low-carbon steel. The rate of biological corrosion of steel samples with Ti-Cu coating is 40% less than on control samples without such a coating. The anti-corrosion efficiency of the XC-5286 coating was 80%. Discussion. The antimicrobial effectiveness of Cu ions primarily depends on their concentration adjacent to the coating surface, which in turn is determined by the rate of release of biocide ions. When immersed in an aqueous solution, copper (I) oxide (Cu2O), which is part of both the XC-5286 coating and the Ti-Cu composite coating formed by thermal spraying, is unstable and, under the influence of chlorine, hydrogen and oxygen ions, quickly oxidizes to more stable divalent copper ions Cu2+. To maintain the required level of antimicrobial effect, the average rate of release of copper ions from contact-type coatings (which includes XC-5286) must be at least 50 μg/cm2 day. The rate of release of Cu ions from a composite Cu-Ti coating formed by plasma spraying is about 20.5 μg/cm2 day, which is almost 2 times less than the required level. This explains the lower antimicrobial efficiency (AE) of Ti-Cu composite coatings compared to XC-5286 enamel, which has an AE value of 80.5%. As shown by full-scale tests, even at low values of the release rate of Cu ions, the coating under study provides effective inhibition of the development of bio corrosion. Conclusions. The work established that the use of the method of detonation thermal spraying made it possible to form a protective Ti-Cu composite coating with anti-corrosion properties on the surface of low-carbon steel. Resume. The work established that the use of the method of detonation thermal spraying made it possible to form a protective Ti-Cu composite coating with anti-corrosion properties on the surface of low-carbon steel. Such Ti-Cu-based coatings can be used not only to protect mechanisms, structural elements and structures operating in mining conditions, but also for their operation in humid climates subject to periodic wetness.

Predicting the magnitude of technogenic earthquakes during underground mining of the Zhezkazgan ore field

Purpose. Determining a relationship between the shear/failure of the rock mass and the technogenic earthquakes caused by them during underground mining of ore deposits with the derivation of an equation for the dependence of the technogenic earthquake indicators for the conditions of the Zhezkazgan copper-ore field. Methods. The research methodology consists of studying and analyzing early research on technogenic earthquakes by the method of statistical data processing. Calculation of rock mass deformation distribution in the study area is based on numerical modeling in the Comsol Multiphysics 5.6 and MATLAB 2020 software package environment. Calculations are performed based on solving a plane problem using the Finite Element Method (FEM). Findings. Based on the transition from the failure area to subsidence and shear values of the overlying rock mass stratum, an equation for the dependence of the earthquake magnitude on the numerical values of the mass subsidence or shear has been obtained. Originality. For the first time, based on the physics and geomechanics of rock mass shear processes, empirical-analytical formulas have been obtained that make it possible to predict the technogenic earthquake magnitude during underground mining of ore deposits in the conditions of the Zhezkazgan copper-ore field. Practical implications. Preliminary predictive calculations made by the obtained formulas for the conditions of the active mine No. 31 of the East-Zhezkazgan mine, ТОО Kazakhmys Smelting, show acceptable results of magnitude value, comparable to in-situ measurements during field mining. This prediction makes it possible to pre-calculate the technogenic earthquake magnitude at the stage of designing mining operations and make appropriate scientifically sound decisions during further mining of the field.

Substantial composition and technological treatment of potassium rocks of the Upper Pechora salt basin

The material composition of potassium and potassium-magnesium salts of the Upper Pechora salt-bearing basin was studied, their lithological variability was established over the area of productive strata, depending on the tectonic features of the foundation. The main mining and geological conditions that complicate the possibility of their extraction and the environmental conditions for organizing mining and processing production of mineral salts were established. The basic physical and technological properties of sylvinite and carnallite rocks mined by the mine method were studied for their enrichment by halurgical and flotation methods. The objectives of the work were: determining the material composition, studying textural and structural features and assessing the technological processing of potassium rocks in the Upper Pechora salt-bearing basin. When solving the problems, the following methods were used: a study of the textural and structural features of sylvinites using the petrographic method; the chemical composition of samples and solutions was analyzed by AES spectrometry; the mineral composition of the water-insoluble residue is determined by X-ray quantitative phase analysis.

Accuracy of the application of mobile technologies for measurements made in headings of the Kłodawa Salt Mine

Abstract The “Kłodawa” salt mine, due to geological conditions and continuous salt extraction, is subject to a range of measurements documenting the speed of changes in the geometry of the chambers. Cyclic surveys are conducted under challenging conditions several hundred metres underground. Consequently, measurement methods used for determining the parameters of the ongoing clamping should be of high precision but also be resistant to dense dust (in fields of active mining) and strong gusts (near ventilation shafts). The research presented here concerns the analysis of the possibilities of solutions offered by modern technologies in mine conditions. Test measurements were conducted at observation stations using linear bases stabilized with metal pins. The base points were located in the aisles, ceiling, and bottom of the chamber in Field 1 of “Kłodawa” salt mine at the depth of 600m. Point clouds mapping the object were acquired using a Leica RTC360 3D laser scanner and two mobile devices: Motorola G100 smartphone and iPad Pro with LiDAR technology using the Pix4Dcatch application. The accuracy of the point cloud from the Leica RTC360 3D laser scanner was determined by comparing it with classic measurements taken with a Leica Disto laser rangefinder. The repeatability and accuracy of the point cloud from a smartphone were examined using statistical analysis based on Pearson’s correlation coefficient and cross-correlation. An attempt was also made to approximate the correlation between the obtained errors and two parameters: the number of images and the size of the object.

Реалізація положень статті 13 Конституції України

The work analyzes the method of implementing the provisions of Article 13 of the Constitution of Ukraine in accordance with the norms of the Tax Code of Ukraine. It was revealed that the Ukrainian people's ownership of the subsoil is improperly implemented and requires radical changes. This issue is solved in the work by determining the components of the price of raw materials extracted in Ukraine. It is proposed to define the sale price as the sum of two components: the extraction price plus rent. Such a price structure automatically monitors the global market situation for each type of raw material, the mining and geological conditions of its extraction in Ukraine, and is universal for all types of raw materials. The work substantiates the necessity of transition to world prices for raw materials and defines the way to implement this possibility. The transition to world prices for raw materials provides a universal way of determining the rent for all types of raw materials as the difference between the world price for the corresponding raw material and the price of extraction of the corresponding raw material in Ukraine. Due to the policy of low wages in Ukraine, most consumers are unable to pay for natural gas and utilities at such rates. To ensure the possibility of applying world prices for energy resources, it is proposed to introduce a discount, the amount of which is equal to the amount of rent. The discount is calculated for each protected consumer depending on the volume of gas consumed according to the readings of his metering devices. The source of funds for granting the discount is part of the rent paid by mining companies in Ukraine. The rest of the consumers must pay the cost of raw materials at world market prices. It is also proposed to change the directions of the use of annuity. Part of the rent should be used to eliminate the budget deficit of the Pension Fund of Ukraine. Most of the rent should be used to form a sovereign national fund and the rest must be transferred to the State Budget.

Optimization of the Layer Location of Extraction Wells Based on the Unpressurized Gas Transport Law.

Protective layer mining is one of the most effective measures to control outbursts of coal seam gas in coal mines. Accurately grasping the overlying rock movement and pressure-relief gas migration patterns under protective layer mining conditions is a prerequisite for efficient surface coalbed methane extraction; it is the basis for green emission reduction in coal mines. A physical model was established using the Ji15-33200 working face of Pingmei Shi Mine as the research object, and a method combining theoretical calculation and numerical simulation was used to obtain the overlying rock movement. In situ stress distribution characteristics of the stope after the upper protective layer was mined to explore the upper protective layer migration rules of pressure-relief gas after mining. On this basis, the location and layer of surface coalbed methane production wells was determined. The research results show that the coal and rock formations on the floor of the goaf experienced a deformation process of compression → expansion → rebalance during the mining process; the stress changes of the overlying and underlying coal strata in the goaf have experienced a process of increasing → decreasing → rebalance; and gas migrates upward through the fissure zone in the coal layer and slowly diffuses in other microfissure areas. When the pressure reaches a certain value, it is enriched in the crack development area and the upper part of the fissure zone; combined with the relevant geological conditions of the study area, it was determined that the upper part of the roof of the Ji16-17 coal seam is a gas-rich area. By comparing three mining vertical wells at different positions in the horizontal direction, it was found that the extraction effect was significant in the "O″ ring, near the excavation face.

Optimizing Retention Bunkers in Copper Mines with Numerical Methods and Gradient Descent

This study examines the optimization of ore receiving bins in underground copper mines, targeting the reduction of rapid wear and tear on bin components. The investigation identifies the primary wear contributors as the force exerted by the accumulated ore and the velocity at which ore particles move. By altering design and operational parameters, the objective is to decrease wear at key points such as transfer areas, thereby improving the efficiency and service life of retention bunkers. A Discrete Element Method (DEM) model of the bin was created and validated against actual mining conditions to study the impact of material flow on wear. The optimization approach used a constrained gradient descent algorithm to minimize factors like particle velocity and pressure force, while maintaining the efficiency of the bin. The findings provide valuable insights for the future design enhancements, potentially improving the operational performance of retention bunkers in the mining industry.

Detection of Safety Signs Using Computer Vision Based on Deep Learning

Safety signs serve as an important information carrier for safety standards and rule constraints. Detecting safety signs in mines is essential for automatically early warning of unsafe behaviors and the wearing of protective equipment while using computer vision techniques to realize advanced safety in the AI and IoT era. This work aims to propose an improved YOLOV4-tiny safety signs detection model applying deep learning to detect safety signs in mines. The dataset employed in this study was derived from coal mines and analogous environments, comprising a total of ten types of safety signs. It was partitioned into training, validation, and test sets following a distribution ratio of (training set + validation set) to test set = 9:1, with the training set to validation set ratio also set at 9:1. Then the attention mechanism ECANet was introduced into the model, which strengthened the network’s learning of places that need attention. Moreover, the Soft-NMS algorithm was used to retain more correct prediction frames and optimize the detection model to further improve the detection accuracy. The Focal Loss function was introduced to alleviate the problem of category imbalance in one-stage safety signs detection. Experimental results indicate that the proposed model achieved a detection precision of 97.76%, which is 7.55% and 9.23% higher than the YOLOV4-tiny and Faster RCNN algorithms, respectively. Besides, the model performed better in the generalization because it avoided the over-fitting phenomenon that occurred in the YOLOV4-tiny and the Faster RCNN. Moreover, the advantages of the improved model were more prominent when detecting small target areas and targets under dim conditions in coal mines. This work is beneficial for the intelligent early warning system with surveillance cameras in coal mines.