矿山牵引变电所供电容量选择的探讨

本文就如何确定矿山电力机车供电容量大小问题，分析了以前采用的“需用系数法”的不足，论述了必须加修正系数的依据，可供同行参考．

理论学习给一个车间带来的变化——记彭县湔江水泥厂矿山车间

湔江水泥厂矿山车间,有干部、工人五十五人,担负着全厂水泥生产原料矿石供应任务。最近,该厂党委到这个车间召开了现场会,通过耳闻目睹,到会同志都异口同声地说:“矿山变了!的确变了!!”在这里,大学无产阶级专政理论蔚然成风,大批修正主义群情激愤,大干社会主义热火朝天。请看看以下几个方面的简单对比,我们就会一目了然。

化腐朽为神奇——评魏继新的新笔记小说

几乎没有人怀疑魏继新在小说创作中会不断沿着其《小镇十条街》系列以及反映川北农村,矿山变革的《望娘滩》、《白岩》等中篇小说系列的现实主义传统开掘下去。然而,当他突然笔锋一转,在《当代》、《四川文学》、《芒种》、《时代文学》等刊物上,于近年一举推出数十篇新笔记小说,从斜刺里杀出一枪时,多少还是令人感到有些意外。

Microseismic signal denoising by combining variational mode decomposition with permutation entropy

Remarkable progress has been achieved on microseismic signal denoising in recent years,which is the basic component for rock-burst detection.However,its denoising effectiveness remains unsatisfactory.To extract the effective microseismic signal from polluted noisy signals,a novel microseismic signal denoising method that combines the variational mode decomposition(VMD)and permutation entropy(PE),which we denote as VMD–PE,is proposed in this paper.VMD is a recently introduced technique for adaptive signal decomposition,where K is an important decomposing parameter that determines the number of modes.VMD provides a predictable eff ect on the nature of detected modes.In this work,we present a method that addresses the problem of selecting an appropriate K value by constructing a simulation signal whose spectrum is similar to that of a mine microseismic signal and apply this value to the VMD–PE method.In addition,PE is developed to identify the relevant effective microseismic signal modes,which are reconstructed to realize signal filtering.The experimental results show that the VMD–PE method remarkably outperforms the empirical mode decomposition(EMD)–VMD filtering and detrended fl uctuation analysis(DFA)–VMD denoising methods of the simulated and real microseismic signals.We expect that this novel method can inspire and help evaluate new ideas in this field.

Numerical simulation of rock deformation during the mineralization of the Xiangshan uranium deposit, Jiangxi province, south China

The Xiangshan uranium deposit in Jiangxi province is one of the most important uranium deposits in China. The aim of our study is to obtain a better understanding of rock deformation and dilation associated with mineralization, to predict the most favorable locations of mineralization, and to assist with future mineral exploration in this deposit. On the basis of geological and structural data from previous studies, we have constructed a coupled deformation and fluid flow numerical model and simulated the faulting deformation and major mechanical factors controlling mineralization in the deposit. Particular attention has been paid to variations in regional stress, distributions of shear strain, volumetric strain and pore pressure. The relationship between the struc-tural/faulting movement and mineralization is obtained through analyzing the deformation state of fault zones. The results suggest that the mineralization is related to volumetric strain, shear strain and pore pressures. The locations displaying all these factors rep-resent the most favorable sites for mineralization. These model results are important for guiding the exploration of new uranium deposits in Xiangshan.

Bioleaching of chalcocite by mixed microorganisms subjected to mutation

Mixed microorganisms with elevated activity of chalcocite-leaching were screened by mutation methods. The original microorganisms collected from acid mine drainage of different sites were mixed and then treated with mutagens NO2^- , diethyl sulfate （DES）, UV and their combinations, respectively. Five groups of mixed microorganisms with much stronger ore-leaching ability were obtained by screening on the leaching media. Among them, group E of mixed microorganisms （treated with 1% DES for 60 min） with the best perfonnance on chalcocite-leaching, increases the content of Cu^2＋ by 101.4% in 20 d of leaching compared with the control culture. In addition, group E is more tolerant to Cu^2＋ in media than the control without mutation treatment. Analysis for the diversity of microbial clones indicates that half of operational taxonomic units （OTUs） in group E are Acidithiobacillus ferrooxidans. These observations suggest that group E might have potentials for industrial application.

Intelligent back analysis of geotechnical parameters for time-dependent rock mass surrounding mine openings using grey Verhulst model

In this paper,we present a new method of intelligent back analysis(IBA)using grey Verhulst model(GVM)to identify geotechnical parameters of rock mass surrounding tunnel,and validate it via a test for a main openings of−600 m level in Coal Mine“6.13”,Democratic People's Republic of Korea.The displacement components used for back analysis are the crown settlement and sidewalls convergence monitored at the end of the openings excavation,and the final closures predicted by GVM.The non-linear relation between displacements and back analysis parameters was obtained by artificial neural network(ANN)and Burger-creep viscoplastic(CVISC)model of FLAC3D.Then,the optimal parameters were determined for rock mass surrounding tunnel by genetic algorithm(GA)with both groups of measured displacements at the end of the final excavation and closures predicted by GVM.The maximum absolute error(MAE)and standard deviation(Std)between calculated displacements by numerical simulation with back analysis parameters and in situ ones were less than 6 and 2 mm,respectively.Therefore,it was found that the proposed method could be successfully applied to determining design parameters and stability for tunnels and underground cavities,as well as mine openings and stopes.

Chaotic time series prediction for surrounding rock's deformation of deep mine lanes in soft rock

Based on the measured displacements,the change laws of the effect of distance in phase space on the deformation of mine lane were analyzed and the chaotic time series model to predict the surrounding rocks deformation of deep mine lane in soft rock by nonlinear theory and methods was established.The chaotic attractor dimension(D) and the largest Lyapunov index(Emax) were put forward to determine whether the deformation process of mine lane is chaotic and the degree of chaos.The analysis of examples indicates that when D>2 and Emax>0,the surrounding rock's deformation of deep mine lane in soft rock is the chaotic process and the laws of the deformation can still be well demonstrated by the method of the reconstructive state space.Comparing with the prediction of linear time series and grey prediction,the chaotic time series prediction has higher accuracy and the prediction results can provide theoretical basis for reasonable support of mine lane in soft rock.The time of the second support in Maluping Mine of Guizhou,China,is determined to arrange at about 40 d after the initial support according to the prediction results.

A CUSP CATASTROPHE, PRECURSORS PATTERN AND EVOLUTION PROCESS OF ROCKBUST OF COAL PILLAR UNDER A HARD ROCK SUBJECT TO ELASTIC SUPPORT

The rockburst of the poal pillar under a thick hard roof stratum is modelled as the instability failure problem of coal pillars under strata subject to elastic support. The instability mechanism of rockburst is studied by applying cusp catastrophic theory. The effects of the stiffness ratio of the system and loads imposed on the system on the rockburst are explicated.The factors affecting rockbursts are discussed. Based on them, the evolution process, the forewarning regularity arid forewarning sings of rockbursts are studied. It is indicated that the subsidence velocity of roof stratum, which increases quickly and tends to infinity, is the forewarning measurable signs of the rockbursts of coal pillar.

The application of modern surveying technology in mining survey

With the unceasing appearance and widespread application of new surveying technology,the present age mining survey has meet huge change.However,lots of prob- lems occurred while using the new techniques since the number of mine is large in China and condition of the mine district is complex,it in some sense influenced the mine exploi- tation and management of China.Summarized the present situation of new technical ap- plication in mining survey,including the advanced instrumentation equipment,the '3S' technology,the information and the network technology and the information fusion tech- nology and so on,and analyzed the problems which exists in the current mining survey,it also provided new ways to present age mining survey from the sustainable development angle.

Determination of volumetric changes at an underground stone mine： a photogrammetry case study

Photogrammetry, as a tool for monitoring underground mine deformation, is an alternative to traditional point measurement devices, and may be capable of accurate measurements in situations where technolo- gies such as laser scanning are unsuited, undesired, or cost-prohibitive. An underground limestone mine in Ohio is used as a test case for monitoring of structurally unstable pillars. Seven pillars were pho- tographed over in a 63 day period, punctuated by four visits. Using photogrammetry, point clouds of the mine geometry were obtained and triangulation surfaces were generated to determine volumes of change over time. Pillar spaUing in the range of 0.29-4.03 m3 of rock on individual rib faces was detected. Isolated incidents of rock expansion prior to failure, and the isolated failure of a weak shale band were also observed. Much of the pillars remained unchanged during the monitoring period, which is indicative of proper alignment in the triangulated surfaces. The photographs of some ribs were of either too poor quality or had insufficient overlap, and were not included. However, photogrammetry was successfully aonlied to multiole ribs in auantifving the oillar geometrv change over time.

Numerical simulation on deformation character of surrounding rock masses of Changjiashan tunnel through the gob of coalmine

Based on the construction project of the Changjiashan tunnel of the freeway,the variety rule of surrounding rock masses of the tunnel through the gob of coalmine wasstudied by using of finite element methed(FEM).The status of the stress and strain,thevariety of the plastic area were simulated in the whole rock mass before and after thetunnel was excavated.The characters of stress and deformation of surrounding rockmasses were analyzed when the tunnel was built.It concluded from the numerical simula-tion that the influence on the tunneling is great when the tunnel passing through the gob ofcoalmine is excavated,and the relative measures should be taken.

Research on monitoring system for slope deformation

The monitoring system for slope deformation which bases on Leica （TCA series） was researched and developed. This system consists of electronic total stations, high precision thermometer, digital barometer, photoelectric frequency adjustor and other related instruments and data collection and processing software. The system can monitor a series of targets automatically to obtain accurate data of distance at predetermined time, besides, it can timely display targets＇ coordinates and deformation value, velocity, etc. in graph as well. To compare of the results of different monitoring time, we can find the problems of mine slope deformation rapidly and accurately.

Mining-induced variation in water levels in unconsolidated aquifers and mechanisms of water preservation in mines

Phreatic water resources are widely found in thick unconsolidated surface layers in western China, where water levels respond sensitively and quickly to large-scale underground mining in conjunction with shallow coal seams. Longwall face #32201 of the Bulianta Coal Mine, in the Shendong coalfield was selected as an industrial trail base, where field observations on ground-water levels were conducted when the working face was below a water-rich area. The space-time variation in the behavior of un-consolidated water levels in response to underground mining and its relation with of advance were observed through the field trials. The basic conditions for water preservation in mines are presented and the mechanisms of water preservation in mining analyzed, given the geological condition of two key strata and a severely weathered layer buried in the overburden. The field trails show that water preservation in mining shallow coal seams can be successful under suitable conditions, providing new technology for envi-ronmental protection in the desert coalfields of northwestern China.

Hazard development mechanism and deformation estimation of water solution mining area

Based on the hazard development mechanism, a water solution area is closely related to the supporting effect of pressure-bearing water, the relaxing and collapsing effect of orebody interlayer, the collapsing effect of thawless material in orebody, filling effect caused by cubical expansibility of hydrate crystallization and uplifting effect of hard rock layer over cranny belt. The movement and deformation of ground surface caused by underground water solution mining is believed to be much weaker than that caused by well lane mining, which can be predicted by the stochastic medium theory method. On the basis of analysis on the engineering practice of water solution mining, its corresponding parameters can be obtained from the in-site data of the belt water and sand filling mining in engineering analog approach.

STUDY ON THE RECLAMATION TECHNIQUE IN A SURFACE MINE WITH CROSS-PIT SYSTEM

A cross-pit system (CPS) could combine the excavation of coal and the reclamation of land together, thus it has been widely used in many countries. Based on a field experiment at Horse Creek mine in Illinois State of the United States, this paper deeply studies the reclamation technique of surface mining by a CPS and comprehensively evaluates its reclamation effect. Problerns and improvements of the reclamation technique are also discussed in this paper.

Analytical solution for stress and deformation of the mining floor based on integral transform

Following exploitation of a coal seam, the final stress field is the sum of in situ stress field and an excavation stress field. Based on this feature, we firstly established a mechanics analytical model of the mining floor strata. Then the study applied Fourier integral transform to solve a biharmonic equation,obtaining the analytical solution of the stress and displacement of the mining floor. Additionally, this investigation used the Mohr–Coulomb yield criterion to determine the plastic failure depth of the floor strata. The calculation process showed that the plastic failure depth of the floor and floor heave are related to the mining width, burial depth and physical–mechanical properties. The results from an example show that the curve of the plastic failure depth of the mining floor is characterized by a funnel shape and the maximum failure depth generates in the middle of mining floor; and that the maximum and minimum principal stresses change distinctly in the shallow layer and tend to a fixed value with an increase in depth. Based on the displacement results, the maximum floor heave appears in the middle of the stope and its value is 0.107 m. This will provide a basis for floor control. Lastly, we have verified the analytical results using FLAC3 Dto simulate floor excavation and find that there is some deviation between the two results, but their overall tendency is consistent which illustrates that the analysis method can well solve the stress and displacement of the floor.

Research on evolution of mining pressure field and fracture field and gas emission features

The relation between mining pressure field-fracture field and gas emission of working face is analyzed, and the concept that there is a stress point （or strain point） among permeability of coal is presented. It is believed that the mutation of coal permeability caused by the sudden loading or unloading of working face roof as periodic weighting occurs is the main reason that a lot of gas pour into the working face. Based on the above concept, the relation is established among abutment pressure during periodie weighting, permeability of coal seam and gas emission, and relation graph is drawn. Then the loading and unloading features of coal at the moment of fracture and non-fracture of main roof are revealed. And finally it is presented that the process of sudden loading or unloading as periodic weighting occurs plays an important role in rupture propagation of coal, analytical movement of gas and gas emission.

矿山守护神

江西省武宁煤矿,有一支在抢险中敢打敢拼,与邪恶势力敢于较真的民兵值勤分队。他们为矿山发展排险解难,积极维护矿区正常的生产、生活秩序,受到人们称赞。

高山上的雄鹰

高山上的雄鹰张国录在海拔三千米以上的一个矿山工地上，有一群英姿勃勃的保安队员在训练，在巡逻，警惕地守卫着矿山的一草一木。这就是青海省大通自治县保安服务公司青海水泥厂某矿山的「保安小分队」。冬去春回，万象更新。山脚下万物欣欣向荣，大地换上了春装，而矿山...