露天矿采空区与火区作业环节安全控制与监管

矿采工作中存在着很多的安全问题,管理得当与否直接关系到人身性命。所以矿采安全问题必须得到很高的重视,尽量避免悲剧的发生。而其中矿采工作中关于采空区与火区的安全问题一直是矿采安全管理当中非常棘手的难题。本文就关于两区安全问题作一些分析。

Study on Critical,Modern Technology for Mining in Gassy Deep Mines

To achieve safe and highly efficient mining in the gassy, deep mines of the Huainan collieries simultaneous coal and gas extraction, and the corresponding ventilation methods were developed. This includes a set of mining procedures and principles which help insure safe and efficient production. Furthermore, green mining, meaning the comprehensive use of emitted gas, proper treatment of the environment and appropriate mine temperature control, is now standard. The concepts of modem mining and the principles of pressure relief are described. Coal-gas simultaneous ex- traction and multi-pressure relief techniques were developed which require a combination of surface and underground gas extraction. The application of Y-ventilation systems, of roadways retained along goafs, of stress control techniques for highly fragile mine roofs and of powerful, automatic and reliable mining equipment contributes to safe operation of modem deep mines. Operating parameters for these techniques are described and the results of their use discussed.

Investigation and characterization of mining subsidence in Kaiyang Phosphorus Mine

In Kaiyang Phosphorus Mine, serious environmental and safety problems are caused by large scale mining activities in the past 40 years. These problems include mining subsidence, low recovery ratio, too much dead ore in pillars, and pollution of phosphorus gypsum. Mining subsidence falls into four categories: curved ground and mesa, ground cracks and collapse hole, spalling and eboulement, slope slide and creeping. Measures to treat the mining subsidence were put forward: finding out and managing abandoned stopes, optimizing mining method (cut and fill mining method), selecting proper backfilling materials (phosphogypsum mixtures), avoiding disorder mining operation, and treating highway slopes. These investigations and engineering treatment methods are believed to be able to contribute to the safety extraction of ore and sustainable development in Kaiyang Phosphorus Mine.

Surface Mine System Simulation and Safety Risk Management

Modem surface mines, either mono-system or multi-systems, need a large fleet of equipment consisting of excavators, loaders, haulers and auxiliary machines. Presently, the complexity of the system, the interference between sub-systems and the lag in management skills has been a bottle neck for improving productivity of the system. Based on the fact that the traditional tools for safety analysis have been insufficient to evaluate systematically and dynamically the safety risks, this paper tries to create a virtual reality tool consisting of human, machine and mines, using Pro/E and the 3D MAX software in order to evaluate visually the operations of typical mining equipment, such as the bucket wheel excavator （BWE）, the shovel, the truck and the dragline. Within this virtual world, the behavior of the system, such as interaction, interference and potential risk can be replayed and reviewed visually. The objective of the study is to identify the critical safety issues of the system and to provide a convenient and powerful tool for safety training and safety management.

Model test of the overburden deformation and failure law in close distance multi-seam mining

Based on characteristic of the associated mining of multi-coal seam and the engineering geological characteristics of overburden,the mining impact pattern of multi- seam mining and the dynamic fracture mechanism of overburden were characterized by applying the engineering geological mechanical model test.The related strata movement parameters and influence area of multi-seam mining were obtained,the strike boundary angle is 61°,the full extraction coefficient is 0.93,the greatest subsidence angle is 81°,the horizontal movement factor is 0.38,the deviation of inflection point/mining deep is 0.11. The development height of caving zone and water flowing fractured zone of multi-seam mining were calculated,is 32 m and 81.5 m separatly.The assess of influence degree of coal layer safety mining is that,there exists the possibility of water and sand inflow when mining,some messures for mine water prevention and control should be used,and the mining thickness should be local strictly limit.

Construction of reasonable pillar group for undersea mining in metal mine

In order to achieve the safe mining in Sanshandao Gold Mine,five schemes of secure pillar group are designed.Using the method of the renormalization group,the failure mechanism of the pillar group is explored,and the safety factor of the pillar system is also obtained.The displacement characteristics,stress-strain laws,distribution of plastic zone and damage range of different pillar group are analyzed using numerical calculation software FLAC3D.To determine a reasonable pillar group scheme,the pillar stability and roof deformation are utilized to evaluate the safety of the pillar group.In addition,the theory of fuzzy comprehensive evaluation is adopted to verify the optimal scheme.The pillar group with the lowest roof deformation value is chosen as the optimal plan,which renders a factor of safety of 2.06 for the pillar group.According to this scheme,pillars with the width of 10 m are set along the strike of undersea deposit with the interval of 50 m.Rib pillars of 15 m in width are set at the location of the exploration line of 127,151 and 167.The analysis can be used to provide guidance for optimal design of pillar structures in undersea mining.

Simulation of Water-Resistance of a Clay Layer During Mining:Analysis of a Safe Water Head

Given previous research and prototypical geological conditions of a mining workface,we simulated fis-sure development in clay layers at the bottom of Quaternary strata and above bedrock,sand and water inrush during mining by model experiments. The results show that V-shaped fissures usually occur in the bottom clay layer at the front top of the active face and that the position of these fissures changes periodically with ground pressure intervals. These fissures occur exactly in the area where the horizontal strain is concentrated. The results also demonstrate that the permeability coefficient of the cracked clay decreases while fissures tend to close. The permeability of the cracked bottom clay layer increases rapidly after a turning point in the permeability coefficient-water head curve (K-H curve) under a certain vertical load. Under static water pressure,the permeability coefficient of cracked clay decreases when load increases. A turning point in the K-H curve showed up and can be seen as a cutoff point to de-cide water inrush under a certain load level. Under an instantaneous water head,the greatest ability of the cracked clay to avoid drastic water inflow is a little higher than that under static conditions.

Safety appraisement on building natural gas pipeline over coal mining subsidence area

The target of the text is to scientifically appraise dynamic development of surface deformation in subsidence area and its influence on groundwork stability of natural pipe and then adopt some technological measures to ensure safe circulation of natural pipeline. Analysed the influence on natural pipeline from coal mining subsidence in the way of pipeline grade variation, vertical curve variation, transverse deformation, horizontal pull and compression deformation and pipe stress variation etc., and described detailed surface subsidence product and its used time among initial phase, active phase and decline phase in the course of surface movement deformation time. In the context of considering surface subsidence that doesn＇t reach basic latter end and residual subsidence quantity, the text confirmed the calculation method of residual deformation in surface subsidence area, and gave the technological measures about building natural gas pipeline in subsidence area finally.

Stability assessment and feature analysis of slope in Nanfen Open Pit Iron Mine

Under the combined influences of special topography and the long term mining in Nanfen Open Pit Iron Mine, many large scale landslide masses appeared in heading side of stope, and tens of millions of iron mine is buried underside, making great economic losses. In order to guide the safety mining and increase the supply quantity, this paper through the use of MSARMA-method and the ''MSARMA evaluation and analytical system for slope stability analysis'' based on this method, which aimed at the quantitative evaluating of the slope stability before and after the actual mining below the slip mass, and the sensitivity analysis for the main influencing factor, providing scientific proof for the parameter optimization of open mine surface slope, the security and sustainable exploitation.

Patterns and security technologies for co-extraction of coal and gas in deep mines without entry pillars

Retaining gob-side entryways and the stability of gas drainage boreholes are two essential techniques in the co-extraction of coal and gas without entry pillars （CECGWEP）. However, retained entryways located in deep coal mines are hard to maintain, especially for constructing boreholes in confined spaces, owing to major deformations. Consequently, it is difficult to drill boreholes and maintain their stability, which therefore cannot guarantee the effectiveness of gas drainage. This paper presents three measures for conducting CECGWEP in deep mines on the basis of effective space in retained entryways for gas drainage, They are combinations of retaining roadways and face-lagging inclined boreholes, retaining roadways and face-advancing inclined boreholes, and retaining roadways and high return airway inclined boreholes. Several essential techniques are suggested to improve the maintenance of retained entryways and the stabilization of boreholes. For the particular cases considered in this study, two field trials have verified the latter two measures from the results obtained from the faces 1111（1） and 11112（1） in the Zhuji Mine. The results indicate that these models can effectively solve the problems in deep mines. The maximum gas drainage flow for a single hole can reach 8.1 m^3/min and the effective drainage distance can be extended up to 150 m or more.

Management present situation and countermeasures of coal mines safety in production

Analyzed of the present situation of Chinese coal mines safety in production and the reasons for coal mining accident,and realized the coal mines safety in production, which should increase the legal safeguards of coal mine safety in production,and safety input,established the comprehensive coal mine safety evaluation system,comprehen- sively enhance quality of coal mine workers,established and improved early warning me- chanism of safety production of coal mine.

Disaster prediction of coal mine gas based on data mining

The technique of data mining was provided to predict gas disaster in view of the characteristics of coal mine gas disaster and feature knowledge based on gas disaster. The rough set theory was used to establish data mining model of gas disaster prediction, and rough set attributes relations was discussed in prediction model of gas disaster to supplement the shortages of rough intensive reduction method by using information en- tropy criteria.The effectiveness and practicality of data mining technology in the prediction of gas disaster is confirmed through practical application.

Similar material simulation of time series system for induced caving of roof in continuous mining under backfill

With the help of similar material simulation test,time series system for induced caving of roof in continuous mining under complex backfill in ore body No.92 of Tongkeng Tin Mine was studied. According to the similarity theory,a two-dimensional similar simulation test-bed was constructed. The stress and displacement that change along with the advance of mining were acquired and analyzed automatically by data system. The processes of continuous mining of ore-block in 5 intervals and artificial induced caving of roof were simulated. The results of the test show that ore body remained as safety roof in thickness of 15 m guarantees the safe advance of stoping work face. Caving of safety roof puts in practice at the first two mining intervals when the third interval of continuous mining is finished,and one interval as the safety distance should be kept all the time between stopping and caving. While mining in the last interval,pre-slotting should be implemented first of all,and the roof of the last two mining intervals is caved simultaneously. Only this kind of time series system can be an efficient and safe way for induced caving of roof in continuous mining.

Orthogonal design and numerical simulation of room and pillar configurations in fractured stopes

Room and pillar sizes are key factors for safe mining and ore recovery in open-stope mining. To investigate the influence of room and pillar configurations on stope stability in highly fractured and weakened areas, an orthogonal design with two factors, three levels and nine runs was proposed, followed by three-dimensional numerical simulation using ANSYS and FLAC3~. Results show that surface settlement after excavation is concentrically ringed, and increases with the decrease of pillar width and distances to stope gobs. In the meantime, the ore-control fault at the ore-rock boundary and the fractured argillaceous dolomite with intercalated slate at the hanging wall deteriorate the roof settlement. Additionally, stope stability is challenged due to pillar rheological yield and stress concentration, and both are induced by redistribution of stress and plastic zones after mining. Following an objective function and a constraint function, room and pillar configuration with widths of 14 m and 16 m, respectively, is presented as the optimization for improving the ore recovery rate while maintaining a safe working environment.

Analysis on produce mechanism and influence factor of CO gas on the coal exploitation working face

Summarized the four main sources of CO gas on the working face based on investigation and local observation: firstly,it analyzed the mechanism that CO gas was produced by spontaneous combustion and oxygenation of gob residual coal;next,it illus- trated the theory that special coal seam deposits natural CO gas,and provided correlative experiment data;and then,it illustrated the reason of the CO gas in working face in- creased relatively in the course of coal cutter's shearing,according to the translation be- tween mechanism energy and inner energy and the rupture of carbon molecule side chain during coal exploitation;lastly,illustrated the reason of CO gas appearance and the rela- tively release quantity during coal mine blasting underground.We find out the source of CO gas on the working face accurately,and provide advantages for appropriate prevention and practical management measures.

Research on new type of numerical method for material creep analysis

Based on the principles of virtual work for continuum medium,the element free Galerkin method to simulate the numerical calculations of steady-state creep was used and the discrete equation was derived in meshlss method for steady-state creep.The es- sential boundary conditions and volume incompressible conditions can be realized by em- ploying the penalty parameters,so the symmetric positive definite system stiffness matrix can be yielded.Results of numerical cases show that element free Galerkin method,with its high accuracy,is much more convenient to deal with the pre-process and post-process, the results by meshless method is in good agreement with the exact solution data.

The impacts of MINER Act of 2006 on the U.S.mining industry

Several high-profile coal mining accidents since 2006 that killed 27 coal miners have prompted the passing of the Mine Improvement and New Emergency Response Act of 2006 (MINER Act) which was signed into law in 2006,and the proposed S-MINER Act of 2007,which passed the House of Representative in early 2008.The four coal mining accidents are described that are believed to be responsible for both the MINER Act and proposed S-MINER Act,and their potential impacts on the U.S.mining industry.

RESEARCH ON RISK OF SPONTANEOUS COMBUSTION IN MINING AREA OF FULLY-MECHANIZED WORKING FACE WITH TOP-COAL DRAWING

Air leakage velocity in intake goaf and distribution of air leakage in mining area are determined by Instantaneous and steady liberation of tracer gas SF6. Gas concentration and temperature in gob are measured and three oxidation areas in goaf are determined. According to oxidation experiment of coal and in-site measurements, the gases of carbon monoxide and dioxide can be produced laraely by coal and oxygen combination at ambient temperature and the temperature of coai and rock In goaf con rise 10℃ due to heat produced by coai and oxygen combination.There is a great risk of spontaneous combustion in neighboring oId gob because of air leakage for pillar mining.

Market-oriented management method of coalmine accident hidden dangers

By analyzing the problems which exist currently in the accident hidden dangers management of the coal mine, this paper proposed a new kind of management method--＂simulating the market＂, in which an operation pattern of simulating the market to transact hidden troubles was constructed. This method introduces ＂Market Mechanism＂ into safe management, and adopts measurable value to describe the hidden dangers such as＂ human behavior, technique, environment, equipments etc.＂. It regards the hidden dangers as ＂the goods produced by labor＂ which are found out by the safety managers and the security inspectors, then sells as ＂commodity＂. By the process of disposing, counterchecking, re-selling, and redisposing. It forms a set of market-oriented closed-form management pattern of coalmine accident hidden dangers. This kind of management method changes the past traditional methods in which the wageworkers treat safety management passively, but to encourage and restrict them to participate in the check-up and improvement of the hidden dangers.

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.