Stability of waste spoils in an area strip mine—geological and geotechnical considerations

Results of investigations into the stability of coal mine spoil consisting of thick clay, saturated sand, and shale overburden in an areal strip mine are presented. Atterberg limits, particle size distributions, and compaction tests were performed to provide index characteristics of the materials. Unconsolidated undrained and consolidated undrained triaxial compression test results on 10·2 cm diameter samples of compacted shale and shale-soil mixtures were used to investigate the short-term and the long-term conditions respectively of the spoil slope. There is evidence that the failure envelope of mine spoil made up of shale or shale-soil mixture is curved. However, stability analyses reveal that the use of strength parameters defined by a linear Mohr-Coulomb envelope yields results that are comparable with those obtained when the non-linear failure envelope is used, provided that such strength parameters are defined at the operating normal stress level on the failure surface. The study illustrates a very good case of spoil instability resulting from very thick overburden soils of low strength and high water content. Results show that the key to achieving stability in such areas lies in an almost total segregation of the soils from the rocks.     

The mechanism of small mining tremors from amplitude inversion

A method of inverting seismic wave amplitudes from mining tremors is proposed to reveal their mechanism. A simple shear-implosive model of a mechanism is proposed. The shapes of theoretical and observed radiation patterns are compared in the least squares norm and the parameters describing the shear-slip together with the ratio of implosive and shear dislocations are optimized. The efficiency of the method, even in the case of a small number of stations, is demonstrated by applying it to weak mining tremors from two mine regions in Czechoslovakia.The weak mining tremors are found to be of a predominantly shear mechanism with a clear coincidence of nodal planes to local tectonics, which could imply their tectonic nature.     

Optimization of the rate of return of the mine production process

Summary The basic foundations of an integrational method of modelling and estimating the economic effectiveness of a deep coal mine production process is presented. The method is founded on the concept of integration of smaller structural elements into larger ones in order to obtain a representational model of the whole mine production process. It involves analysis of the spatial, engineering and time structures of the mining process. The basic structural unit of the production process is the elementary time interval,T, together with a linear function of the approximate intensity of financial outlays or effects. The repeated integration of these elementary time intervals within the spatial, engineering and time structures of the mine production process can be extended to model the whole mine or discrete spatial structure elements.The model may be used to investigate the trends of financial outlays and effects, and their current values updated for arbitrarily assumed updating moments. The model can also be used as an investigation tool for analysing the economical effectiveness of the mine production process.     

A generalized probabilistic approach for slope analysis

Summary A new probabilistic approach is introduced for slope stability analysis, which is general in types of variable distributions and correlations or dependency between variables, and flexible enough to include any adverse impact analysis for blasting vibrations and groundwater conditions.The material strength within a slope area, given in terms of the internal friction angle (ø) and cohesion (c), is randomized in the bivariate joint probability analysis. To be a completely general engineering method, the new probabilistic approach employs the random variable transformation technique: the Hermite model of the Gaussian transformation function, which transforms the experimental histogram of shear strength parameters to the standard Gaussian distribution (=0, ²=1.0).Because a binormal joint probability is analysed on the true probability region projected on the plane of the Gaussian transformed variables, it is an exact solution of slope stability based on the available sample data. No assumption on the shape of the experimental histogram or independency between two random variables is made as in the current probability methods of slope analysis.     

Reinforcement analysis and design of mechanical roof bolting systems in horizontally bedded mine roofs

Summary In order to design roof bolting systems safely and economically, it is essential to understand the flexural behaviour of the immediate roof. Based on the strata sequence, the strata in the immediate roof are divided into three types. The flexural behaviour of the three strata types are investigated in terms of the following effects: roof span, horizontal stress, thickness and Young's modulus of the lowest strata.The suspension reinforcement mechanism is analysed using beam-column theory. The equations for the maximum bending stress, deflection and transferred bolt load for the bolted strata are derived. In the analysis, the bolt load is assumed to be a point load and a horizontal stress is uniformly applied to each stratum. The friction reinforcement mechanism is also investigated. The major function of roof bolting in this case is to create frictional resistance by tensioning the roof bolts so that the individual layers are combined into one single thick layer.A computer program and nomographs are developed for the determination of proper bolting pattern and bolt tension. It is hoped that this development can lead to maximum safety with minimum cost for the design of roof bolting systems in underground coal mines.     

Validation and error analysis of a strata modelling technique

Summary Sources of error are investigated for a two-dimensional finite difference computer program designed to model strata deformation. The program calculates the displacements of a mesh of mass points, by the iterative solution of equations of equilibrium for the stresses acting on each mass point. The effect of errors on both displacement estimates and stress estimates is considered.Round-off errors are discussed analytically, while the effect of choosing too coarse a mesh density is demonstrated by comparison of two runs of the program with identical material properties, but different mesh densities. The influence of boundary conditions and the result of incomplete relaxation of the finite difference equations is estimated by comparison with Kirsch's analytical solution for a thin plate of finite width with a circular hole under unidimensional load.As a result of the analysis, estimators for stresses and displacements are derived, which make allowance for some of the sources of error; suitable boundary conditions for first and subsequent runs of the program are proposed; and a convergence criterion for the iterative process is suggested. These results are then applied to simulations of mining situations, together with various refinements of the basic model, such as separation and slip between adjacent strata, and an allowance for failure of material.     

基于数据挖掘探讨江柏华治疗肺结节的用药规律

目的：运用数据挖掘技术探讨江柏华主任医师治疗肺结节的用药规律。方法：收集2021年12月1日至2022年10月31日于江柏华主任医师门诊首次就诊的肺结节患者的病案资料。采用Excel 2021进行中药频数分析,SPSS Modeler 18.0进行药物关联规则分析,Cytoscape 3.9.1进行网络化展示,SPSS 26.0进行药物系统聚类分析。结果：纳入处方384首,中药165味,总使用频次为13803次,频次＞120次的药物有45种,排前5位者有陈皮、党参、麸炒白术、黄芪、丹参,排前4位的药物功效为补虚、活血化瘀、清热、化痰止咳平喘。药物四气以寒、温、平为主,五味以苦、甘为主,辛味次之,归经以肺、肝、脾经为主,胃经次之。结论：江柏华主任医师认为肺结节的主要病机是正气亏虚、痰瘀内聚,治疗该病以补虚药、活血化瘀药、清热药、化痰止咳平喘药为核心组方。     

基于数据挖掘探析经方治疗晚期肺癌的辨治规律

目的：探讨经方治疗晚期肺癌的辨治规律及处方用药。方法：收集中国知网（CNKI）中运用经方治疗晚期肺癌的病案,通过Medcase V5.2仓公诊籍国医脉案数据记录挖掘系统,运用频数分析与关联规则分析,从临床症状、舌象、脉象、病机、处方用药等多方面对经方治疗晚期肺癌的病案进行数据挖掘。结果：晚期肺癌的主要临床表现有咳嗽、疲倦乏力、食欲不振、胸闷、易醒、入睡困难等;频数较高的舌象有舌质暗红、舌质红、舌质淡红、舌质淡、苔薄白、苔黄腻;频数较高的脉象有细、弦、滑、沉、数、弱;病机主要为癌毒郁肺、肺脾气虚、肺失宣肃、肝郁化火、痰热壅肺、水饮停肺;常用药物有茯苓、法半夏、炙甘草、大枣、桂枝、柴胡等;通过关联规则分析,得到30组关联症状、28组关联病机、30组病机与临床症状关联。结论：应用数据挖掘法能够反映经方治疗晚期肺癌的辨治规律,具有一定的临床指导意义。     

东北矿区资源开采诱发的工程地质灾害与环境损伤特征

以东北老工业基地矿产资源型城市为基础，通过大量的实例和数据介绍了矿产资源开采诱发的工程灾害与环境损伤的内容和特点 ，并指出矿产资源开采诱发的工程灾害与环境损伤中的几个关键科学问题和所应当采用的分析研究方法。