Mining Construction Research Articles

Этапы технического совершенствования центробежных насосов шахтного водоотлива

The article shows the timeliness of an in-depth analysis of changes in the main hydrodynamic parameters of centrifugal pumps for the main drainage of mines, depending on their depth and time history, as well as for processing plants of various technological processes. The requirements for the characteristics of drainage pumping equipment, determined by modern needs for mining in the conditions of technical and economic possibilities for mining, taking into account the geological features of the most accessible deposits explored and accepted for development are determined up by the authors. The aim of the research is to correlate dependencies of the operated centrifugal sectional pumps characteristics with the depths of mines, determined by the needs of mining operations for the extraction of minerals using the underground method. Research objectives are as follows: to establish the main historical stages of the technical development levels of centrifugal pumps for mine drainage and their relationship with the actual depths of mining operations; to propose design solutions to increase energy efficiency and hydrodynamic loading of centrifugal pumps using vortex methods to control the flow of flow into the pump impeller. As a result three main stages of technical improvement of centrifugal pumps for mine drainage over the past 80 years have been established. The criteria for assessing the level of technical excellence of centrifugal pumps for mine drainage in this study are their efficiency, which characterizes the energy efficiency and cost-effectiveness of the equipment, and the pressure coefficient, as an indicator for assessing the level of hydrodynamic loading of the impeller of a centrifugal pump. It has been established that there is a correlation between the pressure and efficiency coefficients depending on the depths of the mines of the corresponding historical period of time. Theoretical dependencies are constructed and the prospects for changes in the pressure coefficient and the effective action of centrifugal pumps in the next decade are shown to ensure their high energy efficiency given the current dynamics of development of mine construction. Correlation dependences between the efficiency coefficient, efficiency of centrifugal sectional pumps and the required height of mine drainage water lifting have been obtained. From the impeller designs analysis of the considered centrifugal sectional pumps, developed according to the theory of L. Euler, it follows that further increase of the stage head coefficient by classical methods has reached its limit and its further increase is possible only through the improvement of hydrodynamic processes with the use of vortex methods of flow control in the flow-hydraulic part of the pump. With the help of correlation equations the predicted values of head coefficients and efficiency are presented based on the analysis of required parameters of centrifugal sectional pumps determined by the dynamics of mine construction development.

The Educational Value and Implementation Strategies of Sports Data Mining Techniques in Physical Education Courses

Abstract Driven by science and technology, the amount of information in today’s society has increased at an unprecedented rate, and the explosion of big sports data has brought challenges to the development of sports data mining. For the education of physical education courses, in order to comply with the educational requirements of the times, based on the rise of the sports recognition model in recent years, this paper carries out sports recognition and evaluation on the basis of data mining to achieve the auxiliary efficacy of physical education course teaching. The study first conducted an in-depth analysis of the data mining technology, and then in order to guarantee the accuracy of the sports behaviour data, this paper compared and analysed different processing methods so as to select a third-order low-pass filter. Subsequently, a sports recognition and assessment model based on the random forest algorithm is proposed, and in the comparative analysis of the algorithms, it can be seen that the recognition method in this paper has the best recognition and assessment effect, and the average recognition rate is as high as 0.924. Based on this, this paper constructs an education management system for the education of physical education courses, which is composed of a data source, a data access layer, a data storage layer, a data analysis layer, an application layer, and a support function, and finally, it takes 30 students of M Physical Education College as the experimental objects to carry out the teaching experiment and to analyse the actual performance base of the students. Before and after the teaching experiment, the experimental group based on the teaching system of this paper to assist in teaching the performance of all indicators by a significant improvement, and P is less than 0.05. At the same time, after the teaching experiment, its average performance is much higher than the control group, which shows that this paper is based on the data mining construction of the physical education teaching system that can actually improve the effect of physical education courses.

Mathematical aspects of occupational risk and its classification considering statistical indicators

Occupational risk emerges as a comparatively novel concept within the regulation of social and labor relations in the Republic of Kazakhstan, serving as an indicator of the risk for loss of work capacity or the death of an employee during the execution of their work-related (official) duties due to an occupational accident. This article elucidates the statistical aspects of оccupational risk content, affirming the mathematical ubiquity and the validity of the scientific framework employed. The methodological foundation for assessing оccupational risk incorporates universally accepted statistical methods for comparison, grouping, and systematisation through the juxtaposition of credible statistical data. The purpose of the study is to employ one of the mathematical approaches to categorise types of economic activity into classes of occupational risk within the mandatory insurance system against accidents for workers fulfilling their occupational duties. The application of machine learning theory with big data across 132 types of economic activities (two-digit, including some five-digit codes) facilitated the execution of a classification procedure, resulting in the segmentation into 22 classes of occupational risk. It revealed the necessity for introducing a five-digit classification and further detailing the types economic activities as the class of оccupational risk increases, such as including the five-digit codes 07101 "Underground mining of iron ores" and 43991 "Mine construction" into class 22 (the highest), delineating from the two-digit codes of the mining and construction industry accordingly. The scientific results were obtained within the framework of program-targeted funding by the Ministry of Labor and Social Protection of the Population of the Republic of Kazakhstan (scientific and technical program No. BR11965728 "Economic problems of safe work and institutional transformations of the insurance mechanism in the Republic of Kazakhstan").

Spatio-temporal evolutionary analysis of surface ecological quality in Pingshuo open-cast mine area, China.

The open-pit mining area is highly affected by human activities, which aggravate soil erosion and disturb surface ecology, bringing many problems and challenges to its environmental management and restoration, which has received widespread attention. The establishment of an objective, timely and quantitative remote sensing monitoring, and evaluation system for the spatio-temporal evolution of the surface ecological environment in the open-pit mining area is of great significance for its environmental protection, management decisions, and sustainable social development. Based on the Google Earth Engine (GEE) platform, this paper uses Landsat images to construct and calculate the remote sensing ecological index (RSEI) of the Pingshuo open-cast mine area (POMA) from 1990 to 2020 and monitor and evaluate its surface ecological environment. Combined with the Theil-Sen median, Mann-Kendall test, and Hurst index, the spatio-temporal process was analyzed. The results showed that the ecological environmental quality of the mining area first decreased and then increased from 1990 to 2020. 1990-2000 was a period of serious ecological degradation, followed by improvement. The overall improvement area reached 87.03%, and the degradation was concentrated in the coal mining area. Between 1990 and 2020, the Hurst index of the mining area was 0.452, indicating that the region has a fragile ecological environment and has difficult maintaining its stability. The global Moran's I mean value of the RSEI of the study area is 0.92, which combined with Moran's scatter plot to indicate that there is a strong positive spatial correlation rather than a random distribution of its ecological environment. During the study period, the impact on the climate of the ecological environmental change of POMA was weak, and human factors such as coal mining, land reclamation, and social construction were the main driving forces for the change in ecological quality. The results of this study reveal the changing trend of surface ecology in the mining area over the past 30 years, which is helpful for understanding its impact mechanism on ecological quality and provides support for the management of the region.

Entity recognition in the field of coal mine construction safety based on a pre-training language model

PurposeSafety management plays an important part in coal mine construction. Due to complex data, the implementation of the construction safety knowledge scattered in standards poses a challenge. This paper aims to develop a knowledge extraction model to automatically and efficiently extract domain knowledge from unstructured texts.Design/methodology/approachBidirectional encoder representations from transformers (BERT)-bidirectional long short-term memory (BiLSTM)-conditional random field (CRF) method based on a pre-training language model was applied to carry out knowledge entity recognition in the field of coal mine construction safety in this paper. Firstly, 80 safety standards for coal mine construction were collected, sorted out and marked as a descriptive corpus. Then, the BERT pre-training language model was used to obtain dynamic word vectors. Finally, the BiLSTM-CRF model concluded the entity’s optimal tag sequence.FindingsAccordingly, 11,933 entities and 2,051 relationships in the standard specifications texts of this paper were identified and a language model suitable for coal mine construction safety management was proposed. The experiments showed that F1 values were all above 60% in nine types of entities such as security management. F1 value of this model was more than 60% for entity extraction. The model identified and extracted entities more accurately than conventional methods.Originality/valueThis work completed the domain knowledge query and built a Q&A platform via entities and relationships identified by the standard specifications suitable for coal mines. This paper proposed a systematic framework for texts in coal mine construction safety to improve efficiency and accuracy of domain-specific entity extraction. In addition, the pretraining language model was also introduced into the coal mine construction safety to realize dynamic entity recognition, which provides technical support and theoretical reference for the optimization of safety management platforms.

Cross-sensitivity analysis of land use transition and ecological service values in rare earth mining areas in southern China

Exploring the cross-sensitivity between land use transformation and ecological service values in rare earth mining areas is of great significance for the development of ecological protection and restoration in rare earth mining areas. To study the impact of land use changes on ecosystem service functions in rare earth mining areas, firstly, the land use change trends in the study area from 2009 to 2019 were analyzed using the land transfer matrix; then the distribution of ecosystem service values and the flow direction of ecosystem service values in the study area were measured based on the ecosystem service value equivalents; a spatial autocorrelation analysis was done on the ecosystem service values to explore their spatial distribution patterns; and finally, the cross-sensitivity coefficient was used to quantitatively assess the extent and direction of the impact of land use change on ecosystem service values. The results show that the land use types in the study area are mainly forest land and farmland, with woodland accounting for the highest proportion of the study area. The ESV changes in the study area are consistent with the trend of land use transformation, with the overall increase and decrease being comparable, and the decrease in ESV is mainly concentrated in the areas with a large increase in mining land and construction land; during the study period, the study area was significantly reduced with low—low cluster areas and the ecological environment was improved; from 2009 to 2014, the ecological sensitivity coefficient is more variable, and is more sensitive to the net conversion between water and desert, from 2014 to 2019, the ecological sensitivity coefficient is less variable, and the most sensitive is the net conversion between cultivated land and water. The study area should be reasonably developed for rare earth resources and the ecological environment around the mining area should be reasonably protected to build an ecological security pattern.

Evaluation of green mine construction level in Tibet based on entropy method and TOPSIS

Green mine construction is a systematic project involving the whole life cycle of mineral resources exploitation and utilization, representing the overall level of development potential. As an important strategic mineral resources reserve base in China, Tibet is rich in mineral resources. In order to calculate the level of green mine construction in Tibet, we obtained different data sources such as statistical yearbooks and mine construction information through field research and discussion. We establish the EMUCIMH evaluation system, select a total of 20 indexes from seven aspects(ecological mining environment, scientific mining method, efficient resource utilization, standardization of energy conservation and emission reduction, intelligent mine construction, standardization of enterprise management and harmonization of mining community),using the Entropy Weight TOPSIS Method to study the problems existing in the process of green mine construction, expecting to provide some references for government departments to make management decisions and for mining enterprises to improve green mine construction. The results show that among the 11 national green mines in Tibet, the construction status is uneven, and there are large differences in the mining methods, the comprehensive utilization of resources, and the ecological environment of mining areas. In contrast, The difference of standardization of enterprise management, intelligent mine construction and the harmonization of mining community is small. Among the specific indicators, in terms of exhaust emissions, mining community harmony and corporate culture are doing well, while they are relatively poor in terms of environmental management and monitoring, technological innovation, and intelligent mine, which need to be improved. Large and medium-sized mines, especially metal mines, the overall level of green mine construction is high, followed by small and medium-sized metal mines and individual Non-metal large mines, and mines with more historical problems faced more difficulties and challenges.

Numerical and theoretical study of load transfer behavior during cascading pillar failure

To further study the load transfer mechanism of roof–multi-pillar–floor system during cascading pillar failure (CPF), numerical simulation and theoretical analysis were carried out to study the three CPF modes according to the previous experimental study on treble-pillar specimens, e.g. successive failure mode (SFM), domino failure mode (DFM) and compound failure mode (CFM). Based on the finite element code rock failure process analysis (RFPA2D), numerical models of treble-pillar specimen with different mechanical properties were established to reproduce and verify the experimental results of the three CPF modes. Numerical results show that the elastic rebound of roof–floor system induced by pillar instability causes dynamic disturbance to adjacent pillars, resulting in sudden load increases and sudden jump displacement of adjacent pillars. The phenomena of load transfer in the roof–multi-pillar–floor system, as well as the induced accelerated damage behavior in adjacent pillars, were discovered and studied. In addition, based on the catastrophe theory and the proposed mechanical model of treble-pillar specimen–disc spring group system, a potential function that characterizes the evolution characteristics of roof–multi-pillar–floor system was established. The analytical expressions of sudden jump and energy release of treble-pillar specimen–disc spring group system of the three CPF modes were derived according to the potential function. The numerical and theoretical results show good agreement with the experimental results. This study further reveals the physical essence of load transfer during CPF of roof–multi-pillar–floor system, which provides references for mine design, construction and disaster prevention.

Research to establish the equation of the principle of claystone breaking under the seabed

The rule of breaking rock has practical significance in the process of controlling the blasting for the optimization of mine production or construction of blasting works. The equations describing the particle size distribution after the explosion are established in an experimental form corresponding to the specific conditions of the blasting work. It only has the meaning of a mathematical regression function and does not reflect the characteristics of the rock type, explosive conditions and explosive results. This research has exploited the theory of rock breaking from the point of view of probabilistic energy to establish the equation of rock breaking of claystone in water. This is a form of semi-empirical equation, which contains 4 empirical coefficients reflecting rock characteristics, explosive conditions, explosive energy absorption characteristics of rocks and actual destruction volume, determined for each type of rock. Through conducting experiments, processing experimental data and solving a system of four equations, four coefficients of the equations that characterize the breaking properties of claystone under the seabed have been found. The error of the average particle size between the actual and calculated values from the equations is less than 7% to 10%. Tt is possible to confirm the accuracy of the semi-empirical equation describing the particle size distribution rule when the claystone is exploded underwater.

Analysis of Carbon Sequestration Effects in Green Mining Construction

This article underscores the significance of the mining industry while acknowledging the detrimental environmental and social repercussions typically associated with conventional mining practices. This paper introduces the transformative concept of green mining construction, which seeks to seamlessly merge the mining sector with environmental stewardship, social responsibility, and economic viability. The article highlights that the adoption of sustainable strategies within green mining construction can amplify carbon sequestration effects, concurrently curbing carbon emissions and bolstering carbon absorption and storage within ecosystems. This holistic approach serves as a potent weapon against climate change, safeguarding the environment, and propelling progress towards sustainable development goals.

Evaluation and dynamic monitoring of ecological environment quality in mining area based on improved CRSEI index model

Large-scale open-pit mining in mining areas will cause serious damage to the ecological environment. Building a “green mine” is an essential part of implementing sustainable development. In order to explore the changing characteristics of the environmental quality of the open-pit mining area and provide a scientific basis for improving the ecological environment of the mining area. Taking Sijiying open-pit mining area as the research area, based on four Landsat images from 2000 to 2022, the four index components of greenness, humidity, dryness and heat were integrated, and an improved remote sensing ecological index CRSEI was constructed by principal component analysis to dynamically evaluate and monitor the ecological environment quality of the mining area. The results show that the average correlation between CRSEI and the index components is higher than the average correlation between the components, indicating that it has a favorable expression effect on the ecological quality of the mining area. The ecological environmental quality of the study area experienced a shift to the poor grade, and the poor ecological quality area was mainly distributed in industrial and mining land and construction land, with the mean CRSEI of 0.668, 0.474, 0.460 and 0.494, respectively. The results of dynamic monitoring showed that the proportion of ecological improvement area (41.43 %) was greater than that of ecological deterioration area (33.29 %) in the study area in the past 22 years, and additional restoration efforts should be made to achieve sustainable development of the ecological environment.

Exploring the Role of Different Cell-Death-Related Genes in Sepsis Diagnosis Using a Machine Learning Algorithm.

Sepsis, a disease caused by severe infection, has a high mortality rate. At present, there is a lack of reliable algorithmic models for biomarker mining and diagnostic model construction for sepsis. Programmed cell death (PCD) has been shown to play a vital role in disease occurrence and progression, and different PCD-related genes have the potential to be targeted for the treatment of sepsis. In this paper, we analyzed PCD-related genes in sepsis. Implicated PCD processes include apoptosis, necroptosis, ferroptosis, pyroptosis, netotic cell death, entotic cell death, lysosome-dependent cell death, parthanatos, autophagy-dependent cell death, oxeiptosis, and alkaliptosis. We screened for diagnostic-related genes and constructed models for diagnosing sepsis using multiple machine-learning models. In addition, the immune landscape of sepsis was analyzed based on the diagnosis-related genes that were obtained. In this paper, 10 diagnosis-related genes were screened for using machine learning algorithms, and diagnostic models were constructed. The diagnostic model was validated in the internal and external test sets, and the Area Under Curve (AUC) reached 0.7951 in the internal test set and 0.9627 in the external test set. Furthermore, we verified the diagnostic gene via a qPCR experiment. The diagnostic-related genes and diagnostic genes obtained in this paper can be utilized as a reference for clinical sepsis diagnosis. The results of this study can act as a reference for the clinical diagnosis of sepsis and for target discovery for potential therapeutic drugs.

Embedding extreme events to mine project planning: Implications on cost, time, and disclosure standards

Extreme events, characterized as infrequent and catastrophic occurrences, can present significant challenges in various industries. These events can be associated with earthquakes, landslides, hurricanes, floods, rainfalls, and wildfires. The mining industry is also highly vulnerable to extreme events because it threats operation sustainability, employees' safety, and environmental compliance. This paper presents a comprehensive analysis of earthquakes in a mining area and evaluates their impacts on a mining operation through a case study based on a mine construction project. To this end, Extreme Value Theory (EVT) using both the Block Maxima (BM) and Peaks Over Threshold (POT) methods was employed to analyze the historical earthquake data and estimate the return levels corresponding to the planned mine project completion time. Furthermore, a Discrete Event Simulation (DES) model was developed to perform a comprehensive risk assessment, allowing for a detailed examination of the potential consequences that a specified magnitude earthquake could have on the project's cost and duration. 1000 earthquake scenarios for the period covering the project life were generated for a thorough risk assessment. The case study focused on a hypothetical open pit mine construction project located in the province of British Columbia, Canada. Historical earthquake data specific to the selected region were analyzed, and the potential consequences of earthquakes on the project were evaluated. According to the results, the return level of 4.7 ML earthquake was obtained corresponding to the return period defined as the planned project completion time. In the event of an earthquake with this specified magnitude, simulation results revealed that there is a 95% probability that the project will experience a delay of at least 6.28% of the project completion time, ultimately leading to project costs exceeding the normal project cost by a minimum of 4.85%. The study highlights the importance of considering extreme natural events, such as earthquakes, in mining project planning and risk mitigation. The results provide valuable insights into the likelihood and potential consequences of earthquakes, contributing to better risk assessment, strategic planning, informed decision-making, and improved project management practices in the mining industry.

Influence of partial cement substitution by ground blast furnace slag on the mechanical properties of phosphogypsum cemented backfill.

Phosphogypsum (PG) stockpiles occupied a large amount of land resources, and serious environmental pollution problems have attracted the attention of countries around the world. Cemented backfill can reduce the environmental problems caused by tailings stockpiles and is an important development trend in green mine construction. To investigate the effect of binder type on the performance of PG cemented backfill, this paper used ground granulated blast furnace slag (GGBFS) to substitute part of Portland cement (PC) as binder and studied the effect of different ratios of binder on the uniaxial compressive strength (UCS), surface crack extension, acoustic emission (AE) characteristics, and microstructure of PG cemented backfill. The results show that substituting part of PC with GGBFS is beneficial to improve the mechanical properties of PG cemented backfill. When PC was substituted by 50% of GGBFS, the 28d UCS of the backfill was increased from 1.535 to 4.539 MPa. Furthermore, the UCS of the backfill gradually increased as the GGBFS substitution level increased, and more AE signals could be monitored during uniaxial compression. Compared with PC, the sulfate in PG participates in the hydration reaction of GGBFS, more hydrated calcium-aluminum-silicate-hydrate (C-A-S-H) gels and ettringite (AFt) are formed, and the microstructure of the backfill is denser, and the required strength can be obtained with less binder. Thus, substituting part PC with GGBFS as a binder can provide an economical and environmentally friendly alternative for the consumption and reuse of large quantities of PG.

Cemented backfill using Ca(OH)2-pretreated phosphogypsum as aggregate: Hydration characteristics, structural features and strength development

Impurities present in phosphogypsum (PG) limited its use as an aggregate in underground mining construction materials. This study pretreated PG with varying Ca(OH)2 contents, and investigated the effect of pretreated PG on the strength development of cemented PG backfill from the perspective of hydration characteristics and structural features. The results show that although a higher Ca(OH)2 content promoted the early-age hydration and therefore increasing unconfined compressive strength (UCS) after 7 days of curing, inappropriate Ca(OH)2 content was found adversely effected the UCS with the extension of curing age. After 28 days of curing, UCS exhibited a decrease over the 2.2–3.2 wt% Ca(OH)2 content range and an increase over the 3.2–6.0 wt% Ca(OH)2 content range. Interestingly, with the extension of curing age to 28 days, little differences were observed in hydration degree between backfill samples, which was incompatible with UCS results. The differences in UCS gain occurred was primarily due to pretreatment-induced structural features changes rather than hydration characteristics influences. Among the various Ca(OH)2 contents, 3.2 wt% Ca(OH)2 resulted in the poorest structural features and therefore lowest UCS (0.30 MPa) after 28 days of curing. These findings provided valuable insights for the optimization of PG pretreatment in cemented PG backfill.

Hub Gene Mining and Co-Expression Network Construction of Low-Temperature Response in Maize of Seedling by WGCNA.

Weighted gene co-expression network analysis (WGCNA) is a research method in systematic biology. It is widely used to identify gene modules related to target traits in multi-sample transcriptome data. In order to further explore the molecular mechanism of maize response to low-temperature stress at the seedling stage, B144 (cold stress tolerant) and Q319 (cold stress sensitive) provided by the Maize Research Institute of Heilongjiang Academy of Agricultural Sciences were used as experimental materials, and both inbred lines were treated with 5 °C for 0 h, 12 h, and 24 h, with the untreated material as a control. Eighteen leaf samples were used for transcriptome sequencing, with three biological replicates. Based on the above transcriptome data, co-expression networks of weighted genes associated with low-temperature-tolerance traits were constructed by WGCNA. Twelve gene modules significantly related to low-temperature tolerance at the seedling stage were obtained, and a number of hub genes involved in low-temperature stress regulation pathways were discovered from the four modules with the highest correlation with target traits. These results provide clues for further study on the molecular genetic mechanisms of low-temperature tolerance in maize at the seedling stage.

Large-scale surface water-groundwater origins and connectivity in the Ordos Basin, China: Insight from hydrogen and oxygen isotopes

The sustainability of water resources is a major challenge for the Ordos Basin and Loess Plateau of China. The basis of effective water management is an understanding of the water cycle process. This study investigated the surface water-groundwater origins and connectivity using stable isotopes (δD and δ18O) of surface water and groundwater in 11 river basins in the Ordos Basin. It was found that the surface water-groundwater origins and hydraulic connection were characterized by regional differences, mainly induced by climatic characteristics, hydrogeological conditions and human activities. Specifically, the impact of thick loess deposits caused surface water and groundwater to take long time to produce a hydraulic connection. In contrast, areas with thin loess deposits and frequent human activities showed a good connectivity between surface water and groundwater. As for water origins, summer precipitation was a common source of surface water and groundwater in the study area, and groundwater discharge was another source of surface water. However, surface water and groundwater were subjected to different degrees of evaporation during receiving precipitation recharge. Notably, thick loess deposits had an impact on groundwater evaporation because both the recharge of precipitation to groundwater and the discharge of groundwater to surface water took a long time. In addition, it was found that frequent human activities (mining, irrigation and urban construction) could weaken the impact of evaporation. This large-scale analysis provided new insights into the origins and connectivity of surface water and groundwater in areas with thick unsaturated zones for water resources management.

Application and characterization of new polymer dust suppression foam in coal mine and tunnel construction space

Severe dust pollution is common in tunnel, coal mine, and other construction sites. Dust suppression foam is a feasible method for dust suppression, but its single function makes it difficult to adapt to complex construction sites. Driving by reconstructing the molecular structure of ecological raw materials and strengthening the network function, a new method of SPI based gel foam dust suppression was proposed in this study. This method was realized through improving the performance of soy protein isolate (SPI) gel by glycosylation and further enhancing the fluidity and foaming performance of SPI by enzymatic hydrolysis. Afterwards, its reaction mechanism and dust suppression mechanism were analyzed. It was found that after the glycosylation of 0.4% SPI with 0.2% xanthan gum (XG) and the subsequent addition of 0.15% transglutaminase (TGase), a relatively stable double reinforcement network structure was generated. This structure was confirmed by Fourier transform infrared spectroscopy and other experiments; to be specific, its viscosity was reduced to 28.3mPa·s, and the foaming multiple was improved by 16.8% than SPI. The particle size of foam was observed to reduce to 20-60μm through a three-dimensional microscope, which is more conducive to wetting and capturing coal dust. Then, the prepared solution was compounded with 1.0% dodecyl dimethyl Amine oxide (OA-12) to develop a dust suppression gel foam and it was sprayed on the coal dust. Through experiments on the mine airflow-dust environment simulation platform, the dust suppression gel foam reached a PM10 suppression efficiency of 98.42%, and remained a total dust suppression efficiency of above 98% after 75 days. Moreover, the validity of the molecular model was confirmed by X-ray photoelectron spectroscopy. The molecular dynamics simulation showed that coal molecules with negative potential attract positively charged OA-12 molecules, and the tail group of OA-12 contacts the hydrophobic sites of the coal at an inclined angle, allowing water molecules to fully contact the coal molecules and improving the wettability; while gel molecules are adsorbed on the surface of coal molecules to play the role of bonding and filling. This research provides a theoretical support for the application of SPI based gel in the field of dust suppression, and develops an environmentally friendly and efficient feasible scheme for dust control in the construction site.

Differential Energy Criterion for Brittle Fracture: Conceptualization and Application to the Analysis of Axial and Lateral Deformation in Uniaxial Compression of Rocks.

This paper discusses modeling the behavior and prediction of fracture of brittle materials. Numerous publications show that progress in this area is characterized by the emergence of a number of new models that meet the requirements of the mining industry, construction and other engineering practices. The authors focus only on one class of models, paying special attention to the compromise between simplicity of solution and versatility of the model. A new version of the model is proposed, taking into account the advantages of previous models. We present a differential energy criterion for brittle fracture substantiated, according to which, fracture occurs at a certain ratio of dissipated and stored (elastic) energy. Fracture is considered as the end of the deformation process with a virtual transformation of the initial material almost without cracks into a real material with cracks. The highest and lowest elastic moduli are analytically determined, respectively, on the ascending and descending branches of the stress-strain curve. A graphical version of the algorithm for determining the brittle fracture point on the post-peak branch of the stress-strain curve is proposed. The modeling results are consistent with the experimental data known from the literature.

Analysis of Eco-Environmental Quality and Driving Forces in Opencast Coal Mining Area Based on GWANN Model: A Case Study in Shengli Coalfield, China

Opencast coal mine production and construction activities have a certain impact on the ecological environment, while the development and utilization of large coal bases distributed in semi-arid steppe regions may have a more direct and significant impact on the eco-environment. Therefore, in-depth studies of the ecological impacts of human activities and natural environmental elements in opencast coal mines in typical semi-arid steppe regions and analyses of their driving forces are of great significance for protecting and restoring regional fragile steppe ecosystems. In this paper, the mining area southwest of the Shengli coalfield, a typical ore concentration area in eastern Inner Mongolia, was selected as the research object. Its remote sensing ecological index (RSEI) was calculated using the Google Earth Engine (GEE) platform to analyze the eco-environmental quality in the mining area and its surrounding 2 km from 2005 to 2021. The geographically weighted artificial neural network model (GWANN) was combined with the actual situation of mining activity and ecological restoration to discuss the driving factors of eco-environmental quality change in the study area. The results showed that: (1) the proportion of the study area with excellent and good eco-environmental quality increased from 20.96% to 23.93% from 2005 to 2021, and the proportions of areas with other quality grades fluctuated strongly. (2) The change in eco-environmental quality in the interior of the mining area was closely related to the reclamation of dump sites and migration of the mining area. (3) The maximum contribution rate of the mining activity factor to the external eco-environmental quality of the mining area reached 43.33%, with an annual average contribution rate of 34.48%; as the distance from the mining area increased, its contribution gradually decreased. This quantitative analysis of the driving forces of RSEI change in the mining area will complement future work in ecological evaluations of mining areas while also improving the practicality of ecological evaluation at the mining scale, thereby further helping the ecological management of mining areas.