Abstract:In recent years,the rapid economic growth,advancement of urbanization,and continuous improvement of con-sumption levels have led to a significant increase in the generation of urban solid waste,including municipal refuse,con-struction debris,industrial solid waste,medical waste,and electronic waste.This surge has resulted in a range of serious issues,such as land resource depletion,environmental pollution,threats to human health,and resource wastage.In re-sponse,the government has introduced the concept of"waste-free cities"along with corresponding policies aimed at redu-cing the generation of urban solid waste at the source and promoting resource utilization.In this context,the sources,clas-sification,and harmful effects of urban solid waste are systematically summarized.It provides a detailed overview of the relevant technologies for the harmless disposal,recycling,and preparation of high-value-added materials from urban solid waste.Building upon this foundation,the paper highlights various demonstration projects conducted in domestic cities,in-cluding waste classification,municipal solid waste incineration for energy generation,organic solid waste gasification and pyrolysis,and the extraction of valuable elements from electronic waste.Finally,corresponding policy recommendations are provided to address several challenges encountered in these demonstration projects,such as incomplete waste classific-ation,mismatch between regional demand for waste-to-energy facilities,inadequate management of secondary pollution from harmful gases,low recycling rates of construction waste,lack of effective heavy metal extraction or harmless solidi-fication technologies for electronic,medical,and industrial waste,and the underdeveloped preparation technologies for high-value-added materials.

Abstract:According to the research,geotechnical engineering is easy to produce large deformation disasters when subjec-ted to complex geological conditions,and the conventional support materials are unable to tolerate the large deformation and failure damage occurs.To cope with the large deformation disaster,the author's team developed a novel ductile mater-ial NPR(Negative Poisson's ratio)bolt.In this paper,in order to explore the macroscopic deformation characteristics of the novel ductile material NPR bolts,indoor tensile comparison experiments of NPR bolts were carried out.The experi-ment adopts a universal testing machine for NPR bolts,and utilizes a camera to record the deformation characteristic of the whole process.The experimental results found that:NPR bolts have better uniform deformation characteristics,and uni-form deformation begins to occur in the early stage of the whole process of tensile deformation failure;The failure frac-tures classification of different steel bars,which were mainly divided into"delamination-type fracture surfaces"and"frac-ture-type fracture surfaces"where the interface between the fibers and the matrix breaks down;Analyzing the uniform de-formation characteristics of the NPR anchors through the mechanical mechanisms and the reason for the insignificant necking phenomenon:it is found that the radius of curvature of NPR steel is larger at the necking place after tensile de-formation failure,so that the necking phenomenon is not obvious,which is due to the relatively small difference between the maximum uniform strain and the maximum strain;Numerical simulation of the effects of the threaded-rib structure and the light-circle structure on the deformation of the steel bars is carried out by the LS-DYNA algorithm:the analysis results show that the threaded-rib structure makes the steel bars better deformed during the tensile process,which is the result of the numerical simulation.The results show that the threaded rib structure makes the steel better deformed uniformly and absorbs the deformation energy in the tensile process.In summary,the macroscopic analysis of the deformation character-istics of the novel NPR bolt ductile material helps to better reveal its static tensile properties,which provides a valuable reference for quasi-static engineering practice.

Abstract:The ecological risk assessment of mining areas aims to evaluate the likelihood and intensity of adverse effects of mining activities on the ecosystem of the mining area.This assessment is crucial for predicting environmental issues,prevention,formulating ecological protection strategies,and sustainable development of the mining industry.The existing research has constructed an evaluation index system that is difficult to obtain indicators,which is not conducive to dynam-ic or real-time risk assessment.This study takes the Gaotouyao mining area as an example,adopts the"Pressure-State-Re-sponse"model and multi-source remote sensing interpretation methods to establish an ecological risk assessment frame-work for mining areas.The pressure index includes distance to goaf,gully density,etc.,the state index includes ecological quality,structure,and service functions,etc.,and the response index includes the distribution of land reclamation planning.The results show that:The weight of the evaluation layer is pressure 0.68,state 0.2,response 0.12,with pressure indicat-ors being dominant;A 10 m resolution ecological risk assessment of the Gaotouyao mining area has been achieved,and the assessment results indicate that the ecological risk is higher in the central part macroscopically and lower in the sur-rounding areas of the mining area;Compared with a single indicator synthesis,compared with the ecological service func-tions of the unmined period,and compared with field survey data,the evaluation results of this paper are highly consistent with the actual situation.The technical framework developed in this paper contributes to the dynamic or real-time assess-ment of ecological risks in mining areas.

Abstract:In inclined thick coal seam fully mechanized caving mining faces,the passage through abandoned roadways ex-hibits more frequent strata movement and ground pressure manifestations compared to horizontal coal seams due to inclin-ation effects,with significantly exacerbated challenges including rib spalling,roof collapse,and pressurizing of hydraulic support.Taking the 1213-1 fully mechanized caving face in Nancha Coal Mine as an engineering case for roadway cross-ing operations,this research systematically combines theoretical modeling,mechanical computation,numerical simulation,and industrial experimentation to elucidate the failure mechanisms and stress-strain characteristics of surrounding rock masses in steeply dipping thick coal seams during abandoned roadway crossings,with comparative analysis of control effi-ciencies between wooden cribbing support scheme and super-high water material backfill scheme.The results demon-strate:① Through establishing 2 mechanical models analyzing shield load interactions with main roof weighting effects and main roof bending moments at different face-roadway positions,combined with 3D numerical modeling of the 1213-1 face crossing operation,it was revealed that the critical factors controlling surrounding rock failure are the coal pillar width between working face and abandoned roadway along with roadway inclination.Vertical stress redistribution intensifies progressively along the face dip direction during mining advancement,showing reduced stress variation magnitude in areas farther from the abandoned roadway under mining disturbance.However,when the caving face approaches the aban-doned roadway,vertical stress fluctuations become significantly amplified,inducing stress concentration phenomena that trigger substantial rock mass deformation.② FLAC3D numerical simulations indicate that super-high water material back-fill significantly enhances the composite strength of surrounding rock in abandoned roadways,effectively mitigates stress concentration within roadway zones,and substantially reduces roof deformation magnitudes.Conversely,wooden crib-bing support demonstrates limited effectiveness,showing minimal differences in vertical stress distribution and deforma-tion patterns compared to unsupported roadway conditions.③ Field trial comparisons demonstrate that wooden cribbing support scheme yield poor support performance characterized by severe roadway deformation,with structural collapse oc-curring in high-inclination zones and subsequent roof material leakage.In contrast,ultra-high water material filling provides dense roof support,enhances roadway surrounding rock integrity,effectively controls deformation,and ensures safe stability during fully mechanized caving face advancement through abandoned roadways.

Abstract:At present,unconventional crude oil production in China accounts for less than 2%of total oil output,while mature oilfields remain the primary contributors to stable production over an extended period.Re-fracturing is a crucial component of reservoir stimulation,and accurate post-fracturing production prediction plays a key role in the selection of target wells for re-fracturing.However,due to internal discontinuities in the reservoir,heterogeneity in porosity and per-meability,and missing critical reservoir parameters,conventional post-fracturing production prediction methods based on empirical formulas or numerical simulations exhibit limited applicability in mature oilfields.Deep learning models provide a promising alternative.Traditional deep learning approaches,such as Recurrent Neural Network(RNN)and long short-term memory(LSTM)networks,suffer from gradient vanishing and limited capability in modeling long-term dependen-cies,making them inadequate for handling petroleum time-series data characterized by high dimensionality,non-stationar-ity,and noise interference.The Transformer architecture,leveraging its multi-head attention mechanism and parallel com-puting capabilities,effectively captures both short-and long-term dependencies in production time series.A comprehens-ive review of re-fracturing technology advancements and recent progress in deep time-series forecasting models has been conducted.Based on this,a Transformer-based deep time-series prediction model is proposed for forecasting post-refrac-turing production in low-efficiency wells.A case study is performed using historical production data from Block W in an oilfield located in the Junggar Basin.This study represents an innovative attempt to establish a theoretical and methodolo-gical framework for large-scale,efficient,and precise well selection in mature oilfields undergoing re-fracturing,offering novel perspectives and solutions for maintaining stable production.Future research should focus on two key directions.First,to control computational costs,optimizing the attention mechanism in the classical Transformer architecture and in-tegrating time-series decomposition techniques is recommended to enable low-computation refracturing production predic-tion.Second,for multi-block collaborative well selection,incorporating domain adaptation theories—particularly ad-versarial domain adaptation and pseudo-label domain adaptation—should be explored to develop a Transformer backbone with transfer learning capabilities.

Abstract:The construction of green mines in China has gone through the stages of germination,pilot projects,and demonstration leadership,and has now entered the stage of comprehensive promotion.The state and local governments have successively introduced support policies to ensure the comprehensive construction of green mines.However,there are still some problems that restrict the construction of green mines.Focuses on the policy framework and construction situation of green mines.By systematically collecting policy documents,mine lists and other data,it examines the charac-teristics of policy design and regional/mineral construction patterns of green mine,and puts forward problems and sugges-tions for the construction of green mines in China.The results show that there are regional differences in the support policies of green mine in China,but all focus on solving the problems of funds and land faced by mines.At the same time,there are obvious regional and mineral differences in the construction of green mines in China.For example,the construc-tion rate in eastern economically developed regions such as Shandong(56.69％)and Jiangsu(44.70％)is relatively high,while in western ecologically sensitive regions such as Tibet(5.66％)and Gansu(6.23％)it is relatively low,which is highly correlated with policy differences;the mineral differences are manifested in the relatively high construction rate in large-scale industries such as oil and gas(29.87％)and coal(26.47％),while in dispersed industries such as black metals(13.82％)and non-ferrous metals(18.61％)it is relatively low.Finally,based on the above analysis,it is pointed out that the construction of green mines in China is mainly faced with the problems of imperfect policy system,unscientific assess-ment mechanism,insufficient endogenous motivation of enterprises and insufficient economic benefits to support the con-struction of green mines,etc.In response to these problems,it puts forward the suggestions of building a sound policy and standard system,improving the third-party assessment mechanism of green mines,establishing the coordination system of resources and environment,and the green mine management system,etc.,to help China's green mines to be built.In re-sponse to these problems,it puts forward proposals to build a sound policy and standard system,improve the third-party assessment mechanism of green mines,establish a resource and environment coordination system,and a green mine man-agement system,etc.,which will help China's green mine construction to advance comprehensively.