Mine Pressure Research Articles

Discussion on the Relationship between Mine Pressure and Gas Gushing Quantity in Coal Seam

Referring to the actual test results of mine pressure and gas gushing quantity in a certain mine, this paper presents a discussion on the relationship between them quantitatively. The results show that there is a close relationship between mine pressure and gas gushing quantity that the gas emission is gradually increasing with the increase of mine pressure, but they are not the relationship of the simple linear increase, gas gushing quantity is also influenced by many other factors.

Safety Evaluation of Mine Pressure Based on Dynamic Fuzzy Theory

Safety Evaluation of Mine Pressure Based on Dynamic Fuzzy Theory

Dynamic Characteristics of Rock and Coal during Deep Upper Protective Mining with Short Distance

The studying of the nonlinear dynamical of rock mass has directly effect on the forecast and the prevention of the disasters in coal mining. However, there have very few tests of the large-scale simulation experiments of dynamic characteristics of rock mass in deep mining. This article focuses on the protective seam in Ji14-31010 of Tian’an Twelvth Mine with the experimental prototype. The simulation model test is carried out to study the mining pressure in Ji14. The displacement and stress of the Ji14 is obtained in the excavation process. The displacement and the stress change law of the underlying coal and rock mass are analyzed from the test data. The analysis results give some suggestions to the project design.

Study on Pressure Regularity of the Fully Mechanized Coal Mining Face and Evaluation on Support Adaptability

Based on the theoretical analysis and field testing, for making clear of the roofs strata behaviors characteristics in the fully mechanized coal mining face in Hongliulin coal mine, and evaluating the adaptability of the support to the roof movement of the working face, this paper gives a collection analysis and evaluation of the rock pressure information during the working faces extraction to get the related technical parameters that can reflect the roof activity rule and the support adaptability analysis and meanwhile to provide some references for the mine pressure monitoring under the similar conditions.

The Affection of Ke of Coal Seam on Strata Behavior

Coal seam burst tendency is one of the main factors of rockburst. The impact energy index is an important indicator to evaluate bursting liability of coal. The research on the impact of coal seam impact energy index on the mining pressure behavior regularity is important for the rockburst prediction and prevention. This paper used FLAC3D numerical calculation software to simulate the mining process of seam workface with different Ke and studied the strata behavior regularity with different Ke. Calculations indicated that the vertical stress peak increased in the middle of the seam workface with Ke increasing and the peak position closer to face should implement the anti-impact measures. However, with Ke decrease, vertical stress superimposes at peak stress increases sharply, gradually increasing vertical stress peak distance away from the face and roadway coal wall and the peak position of moves away from face and roadway coal wall. Therefore, the stress in the roadway and face superimposed at the scour protection measures should be implemented.

Effective Filling Rate in Filling Mining’s Influence on Overlying Strata’s Movement

Similarities and differences of overlying strata movement rule and abutment pressure distribution between filling stope and traditional strope was analysied guided by “practical mine pressure control theory ”. The admissible condition of strata’s depending from bending failure to caving was put forward, and caving zone’s height was analysied on the basis of this. Results showed that caving zone’s height and resistant force required by hydraulic pillar would decrease leapingly ,until the lowest strata transfer into the main roof, and when pressure was stable main roof’s maximum subsidence would become smaller. With the increase of the effective filling rate, filling body’s supporting degree to overlying would increase, when the filling rate reaches to a value, Coal wall’s edge would not appear the plastic zone, the abutment pressure curve is monotone decline with the peak near coal wall edge .

About Methods of Additional Mining Pressure Figuring while Reconstruction of Tunnels

About Methods of Additional Mining Pressure Figuring while Reconstruction of Tunnels

Study and application of a new type of foamed concrete wall in coal mines

A new type of airtight wall with the combination of foamed concrete and pier support was designed in this study. Based on the theories and models related to the foamed concrete and blasting shock load, using the numerical analysis method, this study obtains the new material’s mechanical and destruction laws through analyzing its reaction to different conditions of load (mining and shock waves), airtight wall thickness (1.2, 1.5, 1.8, 2.1 m) and steel pipe diameters (400, 450, 500 and 600 mm). The results show that: ① foamed concrete can have very good suspension, and the pier column support is the main carrier of roof pressure; ② the damaged area of foamed concrete decreases as the foamed concrete thickness increases. Under impact loading, the thickness of the foamed concrete wall plays a more obvious role in retaining its integrity; ③ under the same mining pressure, the damage area increases as the steel pipe diameter increases; ④ with additional mining stress increase, under whether static load or impact load, the stress on the foamed concrete and steel pipe will also increase gradually, therefore the actual airtight wall design will need to be based on specific circumstances in steel stress.

Anthracological analysis of fuel wood used for firesetting in medieval metallic mines of the Faravel district (southern French Alps)

This anthracological study of fuel wood used in the Faravel mines is part of a doctorate research programme conducted on the interrelationship between mines and forests of the Southern Alps during the Middle Ages. The study area is situated in the upper Durance valley, a major mining region from the 11th to the end of the 13th century. Man sought and extracted silver-bearing ore from the valley bottoms to the summit of the mountains. He employed firesetting to attack the hard gneiss bedrock. The study of residual charcoal has been used to measure the impact of the mining economy on the development of mountain forests. The example of the small district of Faravel situated in an upper mountainous region (1900–2150 m altitude), illustrates a supply anchored at subalpine level with a gradual extension of the source area towards the timberline. The anthracological spectra document extinction of Pinus cembra L. at subalpine level and the lowering of the upper limit of the dense forest dominated by Larix decidua Mill. These changes are the result of agropastoral and mining pressure, as testified by both surviving manuscripts and archaeology.

Numerical Simulation on the Stress Distribution of Thin Seam Containing Iron-Sulfide-Cores

Fast Lagrangian Analysis of Continua in three Dimensions was adapted to establish numerical model of thin seam with Iron-sulfide-cores, based on the conditions of thin seam in Yanzhou Mining Area, and the influence of existing cores or not, cores in different positions, cores contents on mine pressure was studied. The results showed that, stress concentration and plastic zone is more easily to be formed in the coal around cores. When there are cores in coal, the bahaviors of abutment stress foreside the working face have no significant differences, the abutment stress curve is fluctuation and width or range of plastic zone little changed, but the boundary of plastic zone is fuzzy and radial. The boundary of plastic zone has some difference with the increasing of cores contents, but other macroscopic mine pressure behaviors has no significant differences. It is helpful to understand spalling mechanism of iron-sulfide-cores in thin seam.

Restriction function of lithology and its composite structure to deformation and failure of mining coal seam floor

In order to research the relationship between deformation and failure depth and lithology and its composite structure, in situ test data on the deformation and structure variation of rocks in different depth of the coal seam floor were utilized on Xinglongzhuang Coal Mine and Baodian Coal Mine in Yanzhou Mining Area by strain testing system and ultrasonic imaging technology in the fully mechanized top-coal working face, and the data on the East Main Haulage of −300 m lever in Peigou Coal Mine in Zhengzhou Mining Area in China were also used. There are obviously different deformation and failure characteristics of similarly homogeneous floor and soft–hard composite structure rocks floor under the mining pressure, which are based on the in situ test data. The research shows that the law of deformation and failure of similarly homogeneous floor is relatively simple; the deformation and failure depth are restricted by the strength of floor rock and has a gradual variation from top to bottom. But the deformation and failure of the interbedded soft–hard rock mining floor are more complex; this kind of structure has a obviously restricting function on the failure depth and deformation degree of the mining floor, and the weak intercalation has a strong constraint effect to the depth of floor failure which implies that the soft rocks have a “cushion effect” on the overlying hard rocks and a “stress diffusion effect” on the underlying hard rocks.

Numerical analysis of seepage flow characteristic of collapse column under the influence of mining

Based on the importance of fractured rock mass seepage research, in order to analyze seepage flow characteristics of collapse column under the influence of mining, a method by embedding fractured rock mass flow solid coupling relationship into FLAC3D internal flow models is presented according to fluid–solid coupling theory and strength criterion. A calculation model of numerical analysis was established, and the influences of mining pressure and plastic damage to pore water pressure and seepage vector change rule were studied. The results show that collapse column is the main channel of confined water seepage upward. The impact is not big when the workface is away from the collapse column. But when the workface is nearing a collapse column, there will be a seepage channel on a side near the workface, in which seepage vector and head are comparatively large. With workface pushing through collapse column, the seepage channel transfers to the other side of the column. In addition, when the plastic damage area within the collapse column breaks through, a “pipeline flow” will be formed within the column, and seepage field will change remarkably and the possibility of water bursting will be greater.

Borehole stress monitoring analysis on advanced abutment pressure induced by Longwall Mining

The paper presented the research on the dynamic advanced abutment stress induced by longwall mining with borehole stress meters on mining side coal mass. Twenty vibrating wire borehole stress meters were installed into the extracting coal mass wall of a first mining roadway of 910 m depth in Zhuji Coal Mine, China, and were used to monitor dynamic changes in vertical and horizontal stresses. Three months of continuous monitoring and further analysis showed that the impacting distance of advanced abutment stress induced by mining in the strike of the working face along its central axis was the farthest, greater than 250 m (the face length is 220 m); it gradually decreased in the radial direction of the face from its central axis outward; the pressure peak was located within 24 m in the front of the mining coal wall; non-synchronous caving of the layered mudstone roof at the stope occurred. Comparison between vertical and horizontal stress increments indicated that the horizontal stress was much smaller than the vertical stress in the coal mass of mining side, while the latter’s magnitude determined the drastic degree of mine pressure manifestation. The study has been applied to determine the advanced support length of the working face and further provide a reliable basis to forecast such dynamic disasters as rock burst, coal and gas outburst, etc., as well as to design the asymmetric supports on both sides of a gateway.

Study on Mine Pressure Behavior of Roadway in Highly Irregular Working Face in Daizhuang Coal Mine

The irregular face mechanized mining is one of the difficult problems in the field of mining engineering. In this thesis, the roadways of 4324 extremely irregular face in DaiZhuang Mine were taken as research object. Through on-site mine pressure observation, the deformation characteristics of the surrounding rock and support force was analyzed. Next the mine pressure appeared rule of the roadways was study. This study benefited that the production of 4324 mining face went on wheels, at the same time, it had important significance to production safety of irregular working face with similar conditions.

Regional gas drainage techniques in Chinese coal mines

China’s rapid economic development has increased the demand for coal. These results in Chinese coal mines being extended to deeper levels. The eastern Chinese, more economical developed, regions have a long history of coal mining and many coal mines have now started deep mining at a depth from 800 to 1500m. This increase in mining depth, geostresses, pressures, and gas content of the coal seam complicates geologic construction conditions. Lower permeability and softer coal contribute to increasing numbers of coal and gas outburst, and gas explosion, disasters. A search on effective methods of preventing gas disasters has been provided funds from the Chinese government since 1998. The National Engineering Research Center of Coal Gas Control and the Huainan and Huaibei Mining Group have conducted theoretical and experimental research on a regional gas extraction technology. The results included two important findings. First, grouped coal seams allow adoption of a method where a first, key protective layer is mined to protect upper and lower coal seams by increasing permeability from 400 to 3000 times. Desorption of gas and gas extraction in the protected coal seam of up to 60%, or more, may be achieved in this way. Second, a single seam may be protected by using a dense network of extraction boreholes consisting of cross and along-bed holes. Combined with this is increased use of water that increases extraction of coal seam gas by up to 50%. Engineering practice showed that regional gas drainage technology eliminates regional coal and gas outburst and also enables mining under low gas conditions. These research results have been adopted into the national safety codes of production technology. This paper systematically introduces the principles of the technology, the engineering methods and techniques, and the parameters of regional gas drainage. Engineering applications are discussed.

Mine Detection Technology in Mine Safe Production

Shirengou iron mine of Hebei iron and steel group Co., LTD owns annual production capacity of two million tons, which is one of the domestic major metal mines. The study of underground safety detection and monitoring system aims at realizing of mining safety and efficiency. This system prevents mine safety accidents effectively and improves mining production efficiently. The establishment of detection and monitoring system plays the significant reference meaning for promoting monitor of domestic mine pressure disaster and safe management level.

Evaluation of the spatio-temporal pattern of urban ecological security using remote sensing and GIS

Research in urban ecology has recently focused on the field of ecological security. Ecological security should be assessed at different scales, from global (to understand some processes of global change) to regional (to understand processes in specific areas) to urban (to consider the processes of urban development). Remote sensing (RS) and geographical information systems (GISs) are widely utilized in ecological security evaluation, with remotely sensed images applied to determine the structure and quantitative indicators of urban ecological systems and GIS to manipulate, analyse, and visualize multisource information in urban ecology. This article focuses on urban ecological security assessment based on multitemporal RS information and GIS. As a case study, the changes in spatial patterns of urban ecological security in Xuzhou City are evaluated during its transformation from a coal mining industrial city to a modern one with decreasing mining production. The popular ‘pressure–state–response’ conceptual model is used to construct an evaluation framework according to geographical properties and data availability. A hierarchical weighted model is adopted to take different factors into account and determine the state of ecological security in the study area. Using Landsat Thematic Mapper/Enhanced Thematic Mapper Plus (TM/ETM+) images as the main RS data source, the derived parameters, such as vegetation index, urban thermal information, and landscape pattern, are integrated to depict the structure and properties of the urban ecological system. Other ancillary information, including mining pressure, water pollution pressure, population density, and ecological flexibility are collected and managed by ArcGIS. The GIS is then used to manage ecological factors derived from remotely sensed data, statistical reports, and geographical data, to evaluate and analyse urban ecological security, and to generate quantitative evaluation and spatial patterns of ecological security. The resulting maps of urban ecological security situations in 1987, 1994, 2000, 2005, and 2007 are analysed in both temporal and spatial dimensions. By analysing urban ecological security in both temporal and spatial dimensions, it is concluded that the ecological security of Xuzhou City is under increasing pressure. Influenced by the pressure of urbanization and mining industry development, the unsafe areas of Xuzhou City have greatly expanded, and with accelerating speed. Finally, suggestions for improving urban ecological security are provided.

Water Inrush Prediction in DongShan Coal Mine Based on GIS and Multi-Source Information

Water inrush in coal mine could be considered as one of the major threats to the security of miners. Thus, it is necessary to forecast the risk of water inrush to ensure the safety of mine production. The mechanism of water inrush and the related factors, such as geological structures, mining pressure, water pressure and water resisting layer are analyzed. The water inrush prediction model was proposed and applied to DongShan coal mine based on GIS and multi-information. Compared with the water inrush status of DongShan coal mine, the results obtained from the water inrush prediction model are satisfied.

Research on Thermal-Insulating Material and Roadway Cooling with High Geotherm

The research aims to develop inorganic thermal-insulating materials of high performance, decrease high geothermal emissions from hot rock to the roadway, reduce the roadway airflow temperature, and achieve mine cooling and energy saving eventually. Firstly, the best proportion of inorganic thermal-insulating materials of high performance was designed, and a test model for thermal conductivity and mechanical analysis has been built. And through the test of thermal-insulating of the material and mechanical properties, the relation equations between vitreous micro-bead content (the main agent of thermal-insulating material) and thermal conductivity, uniaxial compressive strength, confined compressive strength have been obtained respectively. Secondly, the feature, the fitting and coupling features between the experimental models and engineering conditions in practice were analyzed comparatively, which could provide theoretical basis for the design and application of thermal-insulating materials of high performance. The industrial test shows that with thermal-insulating materials of high performance in application, the roadway airflow temperature was reduced significantly and could meet the requirements of mine pressure. Therefore, the research could offer an effective way for the mine thermal-insulating and cooling under high geothermal conditions.

Environment Carrying Capacity Evaluation of Coal Mining in Shanxi Province

China will meet an increasing demand of the energy because of the growth of the economy, coal is being mined largely as the most important energy, but the mining brought in a series of construction of ecological environment problems. This paper established a comprehensive evaluation model for environmental impact of coal mining through three aspects of ecological stability, resource and environment carrying capacity, coal mining pressure with analytic hierarchy process (AHP). Based on this model, authors have evaluated the regional difference of ecological environment carrying capacity of coal mining areas in Shanxi province. The study results may be helpful to scientifically draw up the coal resources development strategy.