Mining Hazards Research Articles

Взаимосвязь геомеханики и недропользования с позиций законодательного определения термина «Недра»

The article presents a historical overview of the development of Geomechanics as a science in the re-search school of the Institute of Mining of the Ural Branch of the Russian Academy of Sciences. A par-ticular attention is given to research into the stress-and-strain state of the rock mass and its changes in the course of operating the mining facilities, which plays a crucial role in securing the stability of struc-tures, mining safety, and prevention of major accidents. To ensure the safety of mining, a complex of research methods is used, including theoretical studies, physical and computer modeling, geophysical sensing of rock masses, ground-surface and satellite geodetic studies of the deformation processes. Geomechanical studies carried out at the Institute of Mining helped to gain new insights into the struc-ture of rock masses, variability of the stress-and-strain state, its mosaic structure as determined by the self-organization process within hierarchical block mass, to reveal the sources of emergencies and cat-astrophic events in mining. Current geomechanical research at the Institute is dedicated to the development of a scientific approach and execution of territory zoning using the criterion of technogenic and natural disasters in mining, studying regularities in the self-organization processes within the rock mass, development of technology to select favorable locations for hazardous and critical mining facili-ties. A special role is played by the prediction of possible changes in the stressandstrain state over time. The Geomechanics Department of the Institute of Mining uses field studies of the rock mass structure, geodetic studies of its mobility, remote sensing using satellite interferometry, and computer simulation of the properties and processes that take place within the rock mass.

Hazards and Control Measures among Artisanal and Small-Scale Gold Miners in Zimbabwe.

Background:In 2017 around 14–19 million miners were exposed to multiple hazards in artisanal and small-scale gold mining (ASGM). ASGM is characterized by basic and compromised mining methods with either very limited control of hazards or none at all. There is little knowledge about health and safety among artisanal and small-scale gold miners in Zimbabwe.Objective:This study explores the interaction between hazards, control measures, and health and safety in Zimbabwe’s ASGM.Methods:Triangulation and mixed methods were applied using standardized questionnaires, Hazard Identification and Risk Assessment (HIRA), focus group discussions (FGDs), and summary notes from in-depth interviews (IDIs). Data were analyzed using descriptive statistics, regression analysis, and thematic analysis.Findings:Quantitative data were collected through HIRA, which was conducted on 34 mining sites. 401 participants, selected through multi-stage sampling, were assessed through standardized questionnaires. Qualitative data was collected through six FGDs, and existing summary notes from 84 IDIs. The most prioritized hazards from the questionnaires were silica dust, noise, and workplace violence as indicated by 238 (62.0%), 107 (26.8%), and 104 (26.7%) respondents (respectively). HIRA identified noise, dust, unsafe shafts, violence, poor sanitation, and poor hygiene as key hazards requiring urgent attention. A key finding of this study was the poor application of the hierarchy of controls in managing workplace hazards. After adjusting for confounders, association with experiencing health and safety challenges was working underground (AOR = 2.0, p = 0.03), workplace violence (AOR = 3.3, p = 0.002), and long working hours (AOR = 2.8, p = 0.019). Injuries and fatalities were common without mitigation strategies.Conclusions:ASGM in Zimbabwe is characterized by underground mining, long working hours, and workplace violence. The poor application of the hierarchy of controls is characterized by increased workplace injuries and fatalities. We recommend following the hierarchy of control measures in ASGM: elimination, substitution, engineering, administrative, and personal protective equipment.

A Trial Evaluation of Rock Core DCDA Absolute Differential Stress Measurement for Routine Quantitative Mining Hazard Assessment in Deep Underground High Stress Mines

A Trial Evaluation of Rock Core DCDA Absolute Differential Stress Measurement for Routine Quantitative Mining Hazard Assessment in Deep Underground High Stress Mines

Characteristics and contributing factors of major coal bursts in longwall mines

AbstractCoal burst has become one of the most serious hazards in longwall coal mines of many countries, and extensive studies have been conducted on the mechanism, prediction, and prevention of coal bursts. However, most of these studies focus on qualitative descriptions of burst environments and specific case analyses. Few studies have been carried out to explore knowledge through a number of past coal bursts in longwall mines. The main objective is to quantitatively analyze the current burst‐prone conditions in longwall coal mines of China and to summarize corresponding lessons. A database consisting of 54 major coal bursts was established. The characteristics and contributing factors of involved coal bursts were analyzed quantitatively, and high‐risk areas that are common in coal mines were then identified. Finally, some suggestions and lessons were proposed. This study may help for identifying controlling factors and high‐risk areas at a specific mine, and it might provide insights into the control of coal bursts in longwall coal mines.

TRAM: A Graphical User Interface for Risk Analysis in the Underground Coal Mines

Over the last few decades, the Australian, New Zealand, Canada, UK, USA and South African mining industries have applied risk management techniques to regulate the hazards in mines. In the Indian mining industry, it was mandated only after the revision of the Coal Mines Regulations in 2017. An effective risk assessment is required to develop a practical risk management plan. TRAM (Tool for Risk Assessment in Mines) is a Graphical User Interface (GUI) that acts as a risk analysis and ranking tool for underground coal mines. This study aims to describe the structure and application of TRAM developed. TRAM is based on the proposed methodology which incorporates Fuzzy logic, the Analytic Hierarchy Process (AHP) and VIKOR, which stands for Multi-Criteria Optimization and Compromise Solution. In the proposed methodology, three risk parameters, consequence (C), exposure (E) and probability (P) were used to assess the risk of identified hazards, hazard groups and overall mine. A case study of risk analysis of an underground coal mine is used to illustrate the application of the TRAM. The developed TRAM has a user-friendly interface, allowing even inexperienced experts to perform effective risk analysis for mines in a short period of time.

CO2 Gas Fracturing in High Dip Angled Coal Seams for Improved Gas Drainage Efficiency at Hashatu Coal Mine

Effective gas drainage for the gassy coal seam is a technological measure to prevent excessive gas outing and gas related mine hazards. CO2 gas fracturing (CO2-Frac) is a new technology for coal mine gas control, and its effectiveness has been proven from many coal fields across China. CO2-Frac has been successfully implemented for gas drainage in single gently inclined coal seam, but it has not been experimented in steeply inclined multicoal seam. In this study, a pilot CO2-Frac project was carried out in Hashatu coal mine, a steeply inclined multicoal seam formation. To attain an effective gas drainage, three different types of CO2- Frac boreholes were drilled and experimented for a long-period gas drainage. One borehole type is the penetrating borehole through two seams, and other two types of in-seam boreholes include strike borehole and up-dipping borehole. With continuous field gas drainage and observation results, the gas drainage efficiency was found to be significantly improved in in-seam borehole and penetration borehole with CO2 fracturing, and the maximum methane flow rate increased 2.4 times for a given borehole length and the efficient drainage radius increased 3–4 times. In addition, the drainage effect of original drainage boreholes within the CO2-Frac circle influenced region was also significantly improved due to the borehole interference. The fractures radius of CO2-Frac in the penetrating borehole was larger than the two types of in-seam boreholes in the steeply inclined seam formation. This may be closely related to the developing property of bedding and cleat system in coal seam. This study provides both theoretical and practical evidence for effectiveness CO2-Frac in the area with steeply inclined angle and multicoal seam formations.

Ground motion characteristics and their cumulative impacts to burst risks in underground coal mines

Ground motions resulting from seismic waves are one of the main factors to trigger coal burst hazards in underground mines. Ground motion induced dynamic impacts may apply to the highly stressed coal/rock mass and initiate dynamic failure. Although ground motion analysis has been widely used in burst-prone hard rock mines for designing support systems, there are only few studies focusing on the understanding ground motion characteristics in coal mines and their relationship with the coal burst damage. Therefore, based on nine-months seismic monitoring in a case study coal mine, this paper conducted a thorough analysis on quantifying ground motions to roadways in both far-field and near-field zones and correlating strong ground motions to actual coal burst damage. The results showed that most far-field ground motions were insignificant, which were less likely to initiate coal burst damage. However, with the same energy levels and hypocentral distances, the seismic events in coal mines can produce higher far-field ground motions than those in hard rock mines. Compared with the far-field ground motions, the near-field ground motions had much higher intensities. The strong dynamic impacts induced by the near-field ground motions may trigger dynamic failure in coal or rock mass when it is already critically stressed. An index called the number of high ground motions (NHGM) was developed to link ground motions with burst risks in roadways. The roadway zone that had experienced a long history of intensive ground motions, indicated by a higher degree of NHGM, were more likely to expect coal bursts in the future.Article highlightsQuantify ground motions to roadways in both far-field and near-field zones in underground coal mines.Demonstrate the relationship between ground motion intensity and coal burst damage.Develop a method to forecast potential burst damage zones in roadways based on historical ground motions.

Effects of ultrathin igneous sill intrusion on the petrology, pore structure and ad/desorption properties of high volatile bituminous coal: Implications for the coal and gas outburst prevention

As the one of the most catastrophic mining hazards, coal and gas outburst seriously threatens the mining safety of collieries. Previous studies indicate that lots of outbursts are closely related to igneous intrusion. Thus, to further understand the influence of igneous intrusion on coal’s physical properties and outburst risk (especially the impacts from ultrathin igneous sill intrusion, which is hard to be detected underground), the combined analyses of petrographic, proximate, pore structure and methane ad/desorption are applied. Results indicate that with the approaching to the ultrathin igneous sill, physical properties of coal change significantly. Due to thermal evolution effect from intrusion, metamorphic grade of coal increases from the high volatile bituminous coal (Ro = 0.6949) of unaffected normal region to the low volatile bituminous coal (Ro = 1.6684), and the altered range of thermal evolution zone is larger than 3 times of the sill thickness but of which the range of strong thermal evolution zone only reaches 0.8 times of the sill thickness. Within the thermal evolution zone: moisture content of coal decrease while the ash content increase when approaching to the sill; micropore volume and specific surface area of the coal are nearly unchanged in the weak thermal evolution zone but reduced in the strong thermal evolution zone, however, methane adsorption capacities of the coal are generally enhanced when comparing to the normal region sample; the transition pores and mesopores pore of the sample close to distal boundary of thermal evolution zone is seriously suppressed (which are 49.21–68.32 % and 20.14–63.31 % of the normal sample, respectively). By comprehensively considering the impact of igneous intrusion on coal, coal locates near the distal boundary of strong thermal evolution zone (about 0.5 times of sill thickness away from the intrusion boundary) seems to have the most serious threat of outburst risk. Additionally, the moisture, ash contents and the gas desorption property of coal has the feasibility to be used as the signs for the hard-detectable small-scale igneous intrusion ahead during roadway tunneling process. Meanwhile, due to the correlation between igneous intrusion and outburst, which can also be regarded as the early warning indicator for outburst prevention.

Mining Hazards to the Safety of Segment Lining for Tunnel Boring Machine Inclined Tunnels

The segment lining is a new type of support structure for mining tunnels. The disturbance of coal excavation leads to the deformation of segment lining and has great hazards to the safety of the tunnels. Based on the tunnel boring machine (TBM) inclined tunnels in Xinjie mine, the ultimate span L0 of the rock beam on the top slab of the coal seam was calculated according to the bending (tension) damage theory. A numerical model was built to simulate the bottom area of the inclined tunnels. During the coal mining, the additional displacements and additional stresses of the segment lining were analyzed, and then the safety factors of the support structure were calculated. Finally, the width of the coal pillar to protect the inclined tunnels was determined. The results showed that the ultimate span of the rock beam on the top of the coal seam is 31.7 m, the deformation of the inclined tunnel has a fish-belly shape, and the deformation leads to the increase of maximum axial force and bending moment. For the inclined tunnels in Xinjie coalmine, a total width of 91.3 m of coal pillar must be reserved to keep the safety factor of the structure higher than 2.0 and prevent the inclined tunnels from the mining hazards.

Prediction and Treatment of Water Leakage Risk Caused by the Dynamic Evolution of Ground Fissures in Gully Terrain

Groundwater leakage in the loess gully terrain is one of the main hazards of coal seam mining at shallow burial depth. The burial depth of the 5−2 coal seam is less than 50 m from the ground in the gully of the study site. The fissures that expand upward after mining can easily penetrate the ground to form a water-conducting channels. During rainy periods, there is a potential risk of groundwater leakage. In order to reveal the characteristics of plane development and the dynamic evolution of gully ground fissures, the typical U-shaped gully in the northern Shaanxi coal mine was studied using the field measurement methods of “On-site measurement” and UAV aerial photography. Based on the experimental platform of ground fissure leakage developed and designed by the team, an indoor test model corresponding to the actual situation was established. In addition, the mathematical models of actual flood inrush, fissure width, and flood flow in the channel were established. The actual mine water flow and the mine drainage capacity were compared and analyzed, thus proposing criteria for classifying gully mining ground fissure collapsed water hazards. These criteria can provide theoretical references for predicting fissure leakage hazard zones in the ground gully of shallow buried coal seams. According to the development height of the water-conducting fissure zone (WCFZ), the treatment methods of ground fissures in gullies under different security conditions were designed, which was applied in the field with good results. The results showed that the treatment methods in this paper could effectively prevent the leakage of groundwater in the gullies along the ground fissures.

Application of Nanoporous Super Thermal Insulation Material in the Prevention and Control of Thermal Hazards in Deep Mining of Metal Mines

As an important energy material, mineral resources have an important role in the rapid growth of the national economy. In recent years, with the enhancement of mining strength and the improvement of mechanized production level, the depth of mining has also increased year by year. Therefore, the number of heat hazards in deep mine mining has increased year by year, and the problem of heat loss in deep mines has become increasingly prominent, which has seriously affected the safe and efficient production of mines. In this paper, the application of nanoporous super insulation materials in the prevention of thermal damage in deep mining of metal mines is studied, and the related theories of nanoporous super insulation materials and the prevention of thermal damage in deep mining of metal mines are understood on the basis of literature data. Nanoporous thermal insulation materials refer to thermal insulation materials with pore diameters in the nanometer range. This material can effectively prevent the collision of gas molecules and prevent the heat conduction of the gas. Then, the application experiment of nanoporous super thermal insulation materials in the prevention and control of heat damage in deep mining of metal mines is carried out. Through experiments, it is concluded that the room temperature thermal conductivity of the experimental material decreases with the increase of the addition of SiO2 aerogel, and the downward trend is linear, and when the heat source temperature is 200°C, the coating surface temperature of the thermal insulation material (excluding aerogel) is 100°C, and the thermal insulation temperature difference is 100°C, while when the coating surface temperature of the aerogel thermal insulation coating is only 60°C, the thermal insulation temperature difference is 140°C. From these data, it can be seen that the thermal insulation performance of nanoporous super thermal insulation materials is better, which verifies the feasibility of its application in the prevention of heat damage in metal mine mining.

Sea Defence Project and a UNESCO World Heritage Monument in Coastal Ghana

Coastal erosion, sand and gravel mining, and open defecation threaten the sustainability and outstanding universal value (OUV) of heritage monuments dotted along the coast of Ghana. A sea defence project has been embarked upon in some areas in Ghana to, among other reasons, safeguard coastal resources, including the historic heritage monuments—castles and forts. This study examined the implications of the project for the sustainability and OUV of a UNESCO World Heritage Site (WHS) along the Ghanaian coastline. The study used a qualitative research design. In‐depth interviews and focus group discussions were conducted to collect data from key stakeholders and analyzed using the thematic method. It became evident that the project has helped reduce oceanic effects, sand and gravel mining hazards, and open defecation in the direct neighbourhood of the site. These have increased the resilience and protective capacity of the monument and enhanced the aesthetic value and sanitation at the site, thereby shoring up the integrity and authenticity of the site and culminating in its enhanced sustainability and OUV. UNESCO, the State Party, Ghana Museums and Monuments Board, Municipal Authority, and Community Leaders should ensure that the advantages that have accrued to the site from the sea defence project are safeguarded and maximized. Additionally, the project should be extended to other coastal areas in the country where similar monuments are located to enable those monuments to derive similar benefits for sustainable development. The study contributes to understanding the protective and aesthetic nexus between coastal engineering and sustainable coastal heritage management.

Integrating Historic Mine Hazard Scoring for Comprehensive Assessment of Abandoned Mine Rehabilitation in the Philippines

Abandoned mines remain a social, environmental, and health-risk problem for the Philippines. These abandoned sites are generally characterized by water-filled pit lakes surrounded with disturbed and exposed soils and sediments containing elevated values of heavy metals and other environmental contaminants. Previous studies with abandoned mines in the Philippines have initiated the use of integrated methods for the assessment of existing abandoned mine site conditions as a tool for decision-making. To further provide a numerical basis for rehabilitation prioritization, this paper aimed to utilize the modified Historic Mine Site Scoring System (HMS-SS) for physical and environmental hazard assessment of the abandoned mercury mine located in Barangay Sta. Lourdes, Puerto Princesa City, Philippines and to produce hazard classification maps based on the generated scores. Results identified the pit lake to be extremely hazardous physically, however, the liquid material (rainfall accumulation in the pit) yielded very low environmental hazard scores with only a few identified points that exceed the regulatory limit. Moreover, the two (2) identified mine tailings sites were found to be physically moderately hazardous but are categorized as extremely hazardous for the environmental aspect. The hazard scoring, coupled with the integrated environmental methods for characterization and development of hazard maps, is recommended as a scientific and quantitative basis for providing decisions in priority of actions to be taken with regards to abandoned mine sites.

Integrated Underground Mining Hazard Assessment, Management, Environmental Monitoring, and Policy Control in Pakistan

This study focused on the significance of underground mining in Pakistan, resulting in the employment of operational staff to undertake the primary tasks of this sector, such as explosions, rock excavation, mineral research, mining-supporting walls, and mine compactivity. Occupational accidents and illnesses arise due to the activities mentioned above because the working circumstances are not optimal. The decision-matrix risk-assessment (DMRA) approach, in which incidents are evaluated according to their severity and probability, was also utilized to improve working conditions, including public health and environment protection. To assess the risks and to select which actions should continue in the same manner, we highlighted hazards that need control measures and, as the last option, those that must be stopped. By taking into account the results of the study, corrective actions were proposed that can help avoid the occurrence of the presented accidents through applying occupational safety and health regulations issued by the Department of Minerals and Mines, which is a governmental entity responsible for both the issuing and the compliance to those regulations. The current study also outlined the requirements that must be reported under mining-related laws.

Predicting roof displacement of roadways in underground coal mines using adaptive neuro-fuzzy inference system optimized by various physics-based optimization algorithms

Due to the rapid industrialization and the development of the economy in each country, the demand for energy is increasing rapidly. The coal mines have to pace up the mining operations with large production to meet the energy demand. This requirement has led underground coal mines to go deeper with more difficult conditions, especially the mining hazards, such as large deformations, rockburst, coal burst, roof collapse, to name a few. Therefore, this study aims at investigating and predicting the stability of the roadways in underground coal mines exploited by longwall mining method, using various novel intelligent techniques based on physics-based optimization algorithms (i.e. multi-verse optimizer (MVO), equilibrium optimizer (EO), simulated annealing (SA), and Henry gas solubility optimization (HGSO)) and adaptive neuro-fuzzy inference system (ANFIS), named as MVO-ANFIS, EO-ANFIS, SA-ANFIS and HGSO-ANFIS models. Accordingly, 162 roof displacement events were investigated based on the characteristics of surrounding rocks, such as cohesion, Young's modulus, density, shear strength, angle of internal friction, uniaxial compressive strength, quench durability index, rock mass rating, and tensile strength. The MVO-ANFIS, EO-ANFIS, SA-ANFIS and HGSO-ANFIS models were then developed and evaluated based on this dataset for predicting roof displacements in roadways of underground mines. The results indicated that the proposed intelligent techniques could accurately predict the roof displacements in roadways of underground mines with an accuracy in the range of 83%–92%. Remarkably, the SA-ANFIS model yielded the most dominant accuracy (i.e. 92%). Based on the accurate predictions from the proposed techniques, the reinforced solutions can be timely suggested to ensure the stability of roadways during exploiting coal, especially in the underground coal mines exploited by the longwall mining. • Roof displacements in underground coal mines were investigated. • Physics-based optimization algorithms were applied in this regard. • ANFIS was applied to determine the relationship of surrounding rocks. • Four AI techniques were proposed to predict roof displacements. • The SA-ANFIS model provided the highest accuracy in predicting roof displacements.

Geological hazards of the Gerecse Hills (Hungary)

ABSTRACT Landslides and related mass movement processes actively pose a threat in the Gerecse Hills (Hungary, Transdanubian Range) by endangering residential and agricultural areas. Several closed or abandoned mining sites and waste deposits are also located in the area. Most of these sites have not been fully remediated, which makes their surroundings dangerous and unsuitable for other use. A multi-hazard map (1: 60,000) was prepared about the geological hazard sources of the Gerecse by collecting and synthetizing data from individual thematic maps and databases. The aim of the map is to provide a comprehensive look at the different but often-interrelated hazard sources of the area. The thematic content of the map consists of three main parts: the result of a statistical landslide susceptibility analysis marking the most landslide-prone slopes, the documented slope failure events, and the areas of hazardous mining sites and their waste deposits.

Quantification study of working fatigue state affected by coal mine noise exposure based on fuzzy comprehensive evaluation

Noise has become a major occupational hazard in coal mines as the level of mechanization has risen. The present paper adopts the analytic hierarchy process and fuzzy comprehensive evaluation to quantitatively evaluate miners’ work fatigue with noise exposure. A fuzzy comprehensive evaluation model of fatigue states is established and validated using the rating of perceived exertion. Results show that with longer exposure to noise, the evaluated fatigue of participants during a continuous work shift increases, and the effect is greater for night-shift miners. The application of fuzzy comprehensive evaluation in fatigue evaluation provides a new scientific method for research on coal mine occupational health and the quantification of the physiological fatigue state of miners. The results of this study can guide evaluations of the fatigue state and improvements to the safety of coal miners exposed to noise.

MLP-Based Model for Estimation of Methane Seam Pressure

One of the principal indicators of the methane hazard in coal mines is gas pressure. This parameter directly affects the methane content in the seam as well as the rate of its release resulting from mining operations. Because of limitations in the existing methods for methane seam pressure measuring, primarily technical difficulties associated with direct measurement and the time-consuming nature of indirect measurement, this parameter is often disregarded in the coal and gas outburst forecasts. To overcome the above-mentioned difficulties, an attempt was made to estimate the methane seam pressure with the use of artificial neural networks. Two MLP-based models were developed to estimate the average and maximum methane seam pressure values, respectively. The analyses demonstrated high correlation between the values indicated by the neural models and the reference values determined on the basis of sorption isotherms. According to the adopted fit criterion, the prediction errors for the best fit were 2.59% and 3.04% for the average and maximum seam pressure values, respectively. The obtained determination coefficients (exceeding the value of 0.99) confirmed the very good predictive abilities of the models. These results imply a great potential for practical application of the proposed method.

Understanding Human Behaviors and Injury Factors in Underground Mines using Data Analytics.

This study aims to understand human behaviors and associated injury causing factors in underground mines using data analytics of historical mining data. Decision tree and association rule were used to provide a statistical analysis of leading factors of hazards in underground mines. Based on the results, we were able to explore hazard feature identification using image feature recognition aiming to provide real-time monitoring for miners to secure healthy and safety operation via wearable computing.

Preliminary sources identification of nitric oxide (NO) emissions in underground mine

Gas hazards in Polish underground mines are a major problem for the ventilation service. Ensuring appropriate environmental conditions is becoming increasingly difficult, especially with the introduction of new, more stringent restrictions on the concentration limits of harmful gases. According to [1], the most dangerous gases in underground mines are carbon monoxide, hydrogen sulfide, nitrogen oxides, c arbon dioxide, sulfur dioxide, and m e thane. T ogether with the introduction of new limit values for the above-mentioned gases by the European Union, it is necessary to accurately identify the sources of their emission in mine workings in order to select an appropriate reduction method. This article presents daily measurements of nitric oxide (NO) concentrations in the workings of one of the copper ore mines owned by KGHM Polska Miedź S.A. The measurement results were used for preliminary analysis of sources of gas emissions to underground workings. The analysis is carried out through a graphical interpretation of the measured values. Knowing the details of the technological processes carried out in the mine under consideration (blasting, diesel engine machines, natural oxidation of nitrogen to NO) the graphs were interpreted by assigning individual values of NO concentrations over time to a specific t echnological process.