Theory,technology and application of grouted bolting in soft rock roadways of deep coal mines

The grouted bolt,combining rock bolting with grouting techniques,provides an effective solution for controlling the surrounding rock in deep soft rock and fractured roadways.It has been extensively applied in numerous deep mining areas characterized by soft rock roadways,where it has demonstrated remarkable control results.This article systematically explores the evolution of grouted bolting,covering its theoretical foundations,design methods,materials,construction processes,monitoring measures,and methods for assessing its effectiveness.The overview encompassed several key elements,delving into anchoring theory and grouting reinforcement theory.The new principle of high pretensioned high-pressure splitting grouted bolting collaborative active control is introduced.A fresh method for dynamic information design is also highlighted.The discussion touches on both conventional grouting rock bolts and cable bolts,as well as innovative grouted rock bolts and cables characterized by their high pretension,strength,and sealing hole pressure.An examination of the merits and demerits of standard inorganic and organic grouting materials versus the new inorganic–organic composite materials,including their specific application conditions,was conducted.Additionally,the article presents various methods and instruments to assess the support effect of grouting rock bolts,cable bolts,and grouting reinforcement.Furthermore,it provides a foundation for understanding the factors influencing decisions on grouted bolting timing,the sequence of grouting,the pressure applied,the volume of grout used,and the strategic arrangement of grouted rock bolts and cable bolts.The application of the high pretensioned high-pressure splitting grouted bolting collaborative control technology in a typical kilometer-deep soft rock mine in China—the soft coal seam and soft rock roadway in the Kouzidong coal mine,Huainan coal mining area,was introduced.Finally,the existing problems in grouted bolting control technology for deep soft rock roadways are analyzed,and the future development trend of grouted bolting control technology is anticipated.

An integrated technology for the absorption and utilization of CO_(2)in alkanolamine solution for the preparation of BaCO_(3)in a high-gravity environment

In this study,an integrated technology is proposed for the absorption and utilization of CO_(2)in alkanolamine solution for the preparation of BaCO_(3)in a high-gravity environment.The effects of absorbent type,high-gravity factor,gas/liquid ratio,and initial BaCl2concentration on the absorption rate and amount of CO_(2)and the preparation of BaCO_(3)are investigated.The results reveal that the absorption rate and amount of CO_(2)follow the order of ethyl alkanolamine(MEA)>diethanol amine(DEA)>N-methyldiethanolamine(MDEA),and thus MEA is the most effective absorbent for CO_(2)absorption.The absorption rate and amount of CO_(2)under high gravity are higher than that under normal gravity.Notably,the absorption rate at 75 min under high gravity is approximately 2 times that under normal gravity.This is because the centrifugal force resulting from the high-speed rotation of the packing can greatly increase gas-liquid mass transfer and micromixing.The particle size of BaCO_(3)prepared in the rotating packed bed is in the range of 57.2—89 nm,which is much smaller than that prepared in the bubbling reactor(>100.3 nm),and it also has higher purity(99.6%)and larger specific surface area(14.119 m^(2)·g^(-1)).It is concluded that the high-gravity technology has the potential to increase the absorption and utilization of CO_(2)in alkanolamine solution for the preparation of BaCO_(3).This study provides new insights into carbon emissions reduction and carbon utilization.

The Philosophy of He(和):Examined from the Perspectives of Technology and Culture

Pre-modern Chinese crafts,such as iron smelting,cookery,medicine,and the production of vehicles,bows,and arrows indicate the traditional Chinese view of technology as being organic,holistic,and comprehensive.This view of technology is guided by the concept of he(和)and employs the means and methods of he,thus achieving the purport of he.In Chinese,the character he(和)possesses positive connotations.It originated from the meaning of"to season;to add flavoring to"(调和)and that of flavors being"perfectly harmonious"(和美).From this sensory experience,he gradually extended to the abstract levels of materiality,humanity,sociality,"order"(wei位),and "power,situation,force"(shi势).Finally,he was elevated to the supreme level of"qi of great harmony"(taihe zhi qi太和之气),which is comparable to the concept of dao(道).The philosophy of he has exerted wide impact on such areas as technology,art,national character,cultural psychology,and behavior patterns,and has become an integral part of China's inherent culture.The paradoxes and deviations of he hold their own profound philosophical implications that merit further exploration.As humanity confronts significant challenges,such as how we can coexist with others,with technology,and with nature,the ancient Eastern wisdom embodied in he continues to possess practical characteristics and value.

A new horizon for neuroscience:terahertz biotechnology in brain research

Terahertz biotechnology has been increasingly applied in various biomedical fields and has especially shown great potential for application in brain sciences.In this article,we review the development of terahertz biotechnology and its applications in the field of neuropsychiatry.Available evidence indicates promising prospects for the use of terahertz spectroscopy and terahertz imaging techniques in the diagnosis of amyloid disease,cerebrovascular disease,glioma,psychiatric disease,traumatic brain injury,and myelin deficit.In vitro and animal experiments have also demonstrated the potential therapeutic value of terahertz technology in some neuropsychiatric diseases.Although the precise underlying mechanism of the interactions between terahertz electromagnetic waves and the biosystem is not yet fully understood,the research progress in this field shows great potential for biomedical noninvasive diagnostic and therapeutic applications.However,the biosafety of terahertz radiation requires further exploration regarding its two-sided efficacy in practical applications.This review demonstrates that terahertz biotechnology has the potential to be a promising method in the field of neuropsychiatry based on its unique advantages.

KEY TECHNOLOGY OF SEMI-CONTINOUS CONVEYOR SYSTEM IN DEEP SURFACE MINE

The key technology of semi-continuous conveyor system decides the successful using of this system. The key technology includes optimal initial building depth of this system,the crusher moving step and the layout of conveyor system are studied, and their calculating models are built up.

Mechanism and monitoring and early warning technology for rockburst in coal mines

On the basis of the massive amount of published literature and the long-term practice of our research group in the field of prevention and control of rockburst,the research progress and shortcomings in understanding the rockburst phenomenon have been comprehensively in-vestigated.This study focuses on the occurrence mechanism and monitoring and early warning technology for rockburst in coal mines.Results showed that the prevention and control of rockburst had made significant progress.However,with the increasing mining depth,several unre-solved concerns remain challenging.From the in-depth research and analysis,it can be inferred that rockburst disasters involve three main problems,i.e.,the induction factors are complicated,the mechanism is still unclear,and the accuracy of the monitoring equipment and multi-source stereo monitoring technology is insufficient.The monitoring and warning standards of rockburst need to be further clarified and im-proved.Combined with the Internet of Things,cloud computing,and big data,a study of the trend of rockburst needs to be conducted.Further-more,the mechanism of multiphase and multi-field coupling induced by rockburst on a large scale needs to be explored.A multisystem and multiparameter integrated monitoring and early warning system and remote monitoring cloud platform for rockburst should be explored and developed.High-reliability sensing technology and equipment and perfect monitoring and early warning standards are considered to be the de-velopment direction of rockburst in the future.This research will help experts and technicians adopt effective measures for controlling rock-burst disasters.

Surrounding rock control of gob-side entry driving with narrow coal pillar and roadway side sealing technology in Yangliu Coal Mine

Gob-side entry driving can increase coal recovery ratio, and it is implied in many coal mines. Based on geological condition of 10416 working face tailentry in Yangliu Coal Mine, the surrounding rock deformation characteristics of gob-side entry driving with narrow coal pillar is analysed, reasonable size of coal pillar and reasonable roadway excavation time after mining are achieved. Surrounding rock control technology and effective roadway side sealing technology are proposed and are taken into field practice. The results showed that a safer and more efficient mining of working face can be achieved. In addition, results of this paper also have important theoretical significance and valuable reference for surrounding rock control technology of gob-side entry driving with narrow coal pillar under special geological condition.

A novel coating technology for fast sealing of air leakage in underground coal mines

Air leakage in underground coal mines presents a serious hazard for coal production and the safety of miners.Coating technology is commonly used as an efficient means for preventing air leakage.To address existing problems with high dust concentrations in large operations involving complex processes and the high cost of traditional coating technology,a novel coating technology that ensures intrinsic safety by utilizing water pressure and wind pressure was developed.This new coating technology was designed to suction and spray,and the technical parameters of its spray performance was also studied.The experimental tests and evaluation indicated the optimum working range is 0.3–0.7 MPa of wind pressure,1.2–10.2 L/min of water quantity,and 1.0–3.5 m of spraying distance.Moreover,this novel coating technology was tested in the Dashuitou Coal Mine in Gansu Province of China.Compared with conventional counterparts,the proposed new technology is safe,efficient,and convenient to operate.During spraying,dust concentrations were kept at less than 10 mg/m3,and the average rebound ratio resilient rate of solid materials was below 13%.After spraying,the average leakage every 100 m was 4 m3/min,and the oxygen volume fraction in the adjacent goaf was approximately 4%,demonstrating excellent air leakage prevention.

Degradation and mineralization of aniline by O_3/Fenton process enhanced using high-gravity technology

The degradation and mineralization of aniline （AN） using ozone combined with Fenton reagent （O3/Fenton） in a rotating packed bed （RPB） was proposed in this study, and the process （RPB-O3/Fenton） was compared with conventional O3/Fenton in a stirred tank reactor （STR-O3/Fenton） or single ozonation in an RPB （RPB-O3）, Effects of high gravity factor, H2O2 dosage, H2O2 dosing method and initial pH on the AN mineralization efficiency were investigated in the RPB-O3/Fenton process, In addition, the behavior of Fe（Ⅱ） was monitored at different H2O2 dosing methods and pH values. Finally, the optimal operation conditions were determined with high gravity factor of 100, initial pH of 5, Fe（Ⅱ） concentration of 0.8 mmol·L-1 and H2O2 dosage of 2.5 ml. Under these conditions, for aniline wastewater at the volume of I L and concentration of 200 mg· L- 1 ,a fast and thorough decay of AN was conducted in 10 min, and the TOC removal efficiency reached 89% in 60 min. The main intermediates of p-benzoquinone, nitrobenzene, maleic acid and oxalic acid were identified by liquid chromatography/mass spectroscopy （LC/MS）, and the degradation pathways of AN in RPB-O3/Fenton system were proposed based on experimental evidence. It could be envisioned that high-gravity technology combined with O3/Fenton processes would be promising in the rapid and efficient mineralization ofwastewater.

Systematic review of mixing technology for recycling waste tailings as cemented paste backfill in mines in China

The development of industry is inseparable from the support of mining.However,mining processes consume a large amount of energy,and increased tailing emissions can have a significant impact on the environment.In the past few decades,the mining industry developed many technologies that are related to mineral energy management,of which cemented paste backfill(CPB)is one of the representative technologies.CPB has been successfully applied to mine ground control and tailings management.In CPB technology,the mixing process is the key to achieving materials with good final quality and controlled properties.However,in the preparation process,the mixed homogeneity of the CPB is difficult to achieve because of fine tailings,high solid volume fraction,and high viscosity.Most research focused on the effect of mixing ingredients on CPB properties rather than on the preparation process of the CPB.Therefore,improving the performance and reducing the production cost of CPB by optimizing the mixing process are important.This review summarizes the current studies on the mixing technology of CPB and its application status in China.Then,it compares the advantages and disadvantages of multiple mixing equipment and discusses the latest results and research hotspots in paste preparation.Finally,it concludes the challenges and development trends of mixing technology on the basis of the relevant application cases in China to promoting cement-based material mixing technology development.

Study on Semi-Continuous Technology System for Soft Material Stripping in Large Surface Mines

Continuous and semi-continuous mining technology has become the main trend of modern surface mines in the world. According to the deposit characteristics of coal basin in China and Chinese situation,this paper discussed the new semi-continuous technology── shovel - transfer wagon-belt conveyor and its application prospect in large surface coal mines in China.

Monitoring of coal-mine goaf based on 4D seismic technology

The range of coal-mine underground goaf has continuously expanded over time.Caving,fracture,and deformation zones have also changed,thereby inducing coal-mine water inrush and other environmental disasters.In this study,4 D seismic monitoring technology that is effective in reservoir development was used to monitor abnormal changes in coal-mine underground goaf to explore the feasibility of the method.Taking a coal mine in Hancheng,Shaanxi as an example,we used the aforementioned technology to dynamically monitor the abnormal changes in the goaf.Based on the 4 D seismic data obtained in the experiment and the abnormal change characteristics of the coal-mine goaf,the method of 4 D seismic data processing in reservoir was improved.A set of 4 D data processing flow for the goaf was established,and the anomalies in the surface elevation and overlying strata velocity caused by collapse were corrected.We have made the following improvements to the method of 4 D seismic data processing in the reservoir:(1)the static correction problem caused by the changes of surface elevation and destruction of the low-velocity layer has been solved through fusion static correction to comb the low-frequency components of elevation statics with the high-frequency components of refraction statics;(2)the problem of overlying strata velocity changes in the goaf caused by collapse has been solved through the velocity consistency method;(3)the problem of reflection event pull-down in the disturbance area has been solved through space-varying moveout correction based on cross-correlation;and(4)amplitude anomalies in the coal seam caused by the goaf have been addressed using the correction method of space-varying amplitude.Results show that the 4 D seismic data processing and interpretation method established in this study is reasonable and effective.

Support technology for mine roadways in extreme weakly cemented strata and its application

For the engineering geology conditions of bad mine roadway roof and floor lithology in extremely weak cemented strata, the best section shape of the roadway is determined from the study of tunnel surrounding rock displacement, plastic zone and stress distribution in rectangular, circle arch and arch wall sections, respectively. Based on the mining depth and thickness of the coal seam, roadway support technology solutions with different buried depth and thickness of coal seam are proposed. Support schemes are amended and optimized in time through monitoring data of the deformation of roadway, roof separation, l-beam bracket, bolt and anchor cable force to ensure the long-term stability and security of the roadway surrounding rock and support structure. The monitoring results show that mine roadway support schemes for different buried depth and section can be adapted to the characteristics of ground pressure and deformation of the surrounding rock in different depth well, effectively control the roadway surrounding rock deformation and the floor heave and guarantee the safety of construction and basic stability of surrounding rock and support structure.

A remining technology of underground coal gasification at Zhongliangshan Coal Mine

The field trail used a mixture of steam and air with various levels of oxygen en- richment.Steady conditions were achieved in the field trail which produced high quality hydrogen-enriched syngas.To understand and optimize the UCG process,a simplified heat and mass transfer model was presented,providing a predictive tool for temperature and the major constituents of the syngas production.The model is compared with the field trail measurements for air and two levels of oxygen enrichment,showing reasonable agreement for the channel temperature and product syngas concentration profile.

Water source identification in mines combining LIF technology and ResNet

The problem of mine water source has always been an important hidden danger in mine safety production.The water source under the mine working face may lead to geological disasters,such as mine collapse and water disaster.The research background of mine water source identification involves many fields such as mining production,environmental protection,resource utilization and technological progress.It is a comprehensive and interdisciplinary subject,which helps to improve the safety and sustainability of mine production.Therefore,timely and accurate identification and control of mine water source is very important to ensure mine production safety.Laser-Induced Fluorescence(LIF)technology,characterized by high sensitivity,specificity,and spatial resolution,overcomes the time-consuming nature of traditional chemical methods.In this experiment,sandstone water and old air water were collected from the Huainan mining area as original samples.Five types of mixed water samples were prepared by varying their proportions,in addition to the two original water samples,resulting in a total of seven different water samples for testing.Four preprocessing methods,namely,MinMaxScaler,StandardScaler,Standard Normal Variate(SNV)transformation,and Centering Transformation(CT),were applied to preprocess the original spectral data to reduce noise and interference.CT was determined as the optimal preprocessing method based on class discrimination,data distribution,and data range.To maintain the original data features while reducing the data dimension,including the original spectral data,five sets of data were subjected to Principal Component Analysis(PCA)and Linear Discriminant Analysis(LDA)dimensionality reduction.Through comparing the clustering effect and Fisher's ratio of the first three dimensions,PCA was identified as the optimal dimensionality reduction method.Finally,two neural network models,CT+PCA+CNN and CT+PCA+ResNet,were constructed by combining Convolutional Neural Networks(CNN)and Residual Neural Networks(ResNet),respectively.When selecting the neural network models,the training time,number of iterative parameters,accuracy,and cross-entropy loss function in the classification problem were compared to determine the model best suited for water source data.The results indicated that CT+PCA+ResNet was the optimal approach for water source identification in this study.

Development and technology status of energy storage in depleted gas reservoirs

Utilizing energy storage in depleted oil and gas reservoirs can improve productivity while reducing power costs and is one of the best ways to achieve synergistic development of"Carbon Peak–Carbon Neutral"and"Underground Resource Utiliza-tion".Starting from the development of Compressed Air Energy Storage(CAES)technology,the site selection of CAES in depleted gas and oil reservoirs,the evolution mechanism of reservoir dynamic sealing,and the high-flow CAES and injection technology are summarized.It focuses on analyzing the characteristics,key equipment,reservoir construction,application scenarios and cost analysis of CAES projects,and sorting out the technical key points and existing difficulties.The devel-opment trend of CAES technology is proposed,and the future development path is scrutinized to provide reference for the research of CAES projects in depleted oil and gas reservoirs.

A frequency servo SoC with output power stabilization loop technology for miniaturized atomic clocks

A frequency servo system-on-chip(FS-SoC)featuring output power stabilization technology is introduced in this study for high-precision and miniaturized cesium(Cs)atomic clocks.The proposed power stabilization loop(PSL)technique,incorporating an off-chip power detector(PD),ensures that the output power of the FS-SoC remains stable,mitigating the impact of power fluctuations on the atomic clock's stability.Additionally,a one-pulse-per-second(1PPS)is employed to syn-chronize the clock with GPS.Fabricated using 65 nm CMOS technology,the measured phase noise of the FS-SoC stands at-69.5 dBc/Hz@100 Hz offset and-83.9 dBc/Hz@1 kHz offset,accompanied by a power dissipation of 19.7 mW.The Cs atomic clock employing the proposed FS-SoC and PSL obtains an Allan deviation of 1.7×10^(-11) with 1-s averaging time.

Reliability Theory Study of Combined Mining Technology System in Surface Mines

The connection between all the single systems iu combined technology is analysed, and the mine engineering reliability is calculated in any area of the mines using combined technololgy system. The reliability design and distribution method in this system is put forward, thus the basis is set for the decision to raise the total production capability or the surface mines in which the combined system is used.

Preliminary study on treatment of waste organic matter from livestock by bacteria-mineral technology

The present study dealt with relationships between the degradation and humification process that the organic matter underwent during bacteria-mineral technology. An inverse correlation was found between the protein, lipid, and some of the humification indices considered, suggesting that the humification theory is actually humic substances produced from simple-structured natural organic substrates. Weight-average molecular weight （Mw）, number-average molecular weight （Mn）, and the ratio Mw/Mn of dissolved organic matters at different stages of the process were measured by gel permeation chromatography. The results showed that Mn and Mw increased with reaction time from 352 to 17,191, and from 78,707 to 104,564, respectively. The ratio of Mn/Mw decreased from 223.3 to 6.1. This reflected the growth of the polymerization degree of dissolvable organic matters in the process; furthermore, it indicated the formation of complex molecules （humic substances） from more simple molecules. Bacteria-mineral water （BMW） （the effluent of the process） treatments can exert hormone-like activity for enhanced seed germination of wheat and rice and greatly improved chlorophyll synthesis in wheat and rice leaves, Major polyamines （plant regulators） putrescine, spermidine, and spermine, were found in BMW by a high performance liquid chromatography （HPLC） method, which may explain the hormone-like activity of BMW.

NEW FLOTATION TECHNOLOGY OF REFRACTORY GRAPHITE ORES IN PINGHE MINE

Pinghe graphite of Sichuan Province is the fine grain crypto-crystal mixed refractory graphite ores. This paper introduces a new flotation technology on this kind of ores of one time rough grinding-rougher flotation-scavenger flotation-five times regrindings and seven times beneficiations-middlings regrinding and reflotation, which can suc-cessively produce ——325 mesh state standard powdered graphite products.