Advanced Materials Research Vols. 734-737

Abstract: Numerical simulation analysis were done on breaking arch developing and evolving process of both single stope and coal seams mining field by FLAC3D. Results show that in single strope's advancing process, breaking arch's height would be different as strope's length changes, and breaking arch's height was decided by strope's length; in composite strope, as the coal pillar increasing, composite strope's breaking arch gradually develops from superposition state to independent state; as the strope's length changing composite strope's superposition state tend to balance

Abstract: In order to get reasonable pillar position, this paper researched 20 m inclined pillar abutment pressure spread distribution rule on multiple inclined coal seam roof and floor, based on these lower coal seam have three pillar position can be determined, they were in the central or upside or downside. We are from three aspects to respectively analysis degree of pillar relief, pillars peak pressure concentration factor and pressure spread depth of the floor when pillar layout in different location. The results show that pillar abutment pressure concentration factor along the pillar normal and gravity synthesis direction spread, and with flat oval symmetrical decline distribution on roof and floor, also obtain the upper and lower pillar staggered arrangement is beneficial to the upper pillar pressure relief, at the same time, pillar itself abutment pressure peak coefficient is lower, floor propagation depth is smaller. In short, if the coal seam under inclined pillar want to layout pillars, upside better than downside, and downside is better than vertical, which the result has certain guiding significance for inclined coal seam of reasonable choice pillar position.

Abstract: To analyse the outburst hazard of heading face in real time, based on the mechanism of coal and gas burst and its forecasting principle, four real-time predictive indicators were proposed, which involve three aspects: crustal stress, gas, physical and mechanical properties of coal, and had a verification test. The results show that the real-time predictive indicators are in good agreement with the traditional indicators, whose deviation are mainly caused by gas exceeded. With the monitoring data in monitoring system, the outburst hazard of heading face could be predicted in real time, which could help to prevent outburst.

Abstract: The research of slope failure, which is one of the main types of natural disasters, has become a hot topic. Effective landslide forecast can improve the early warning system of landslides and mitigate the landslide disasters. In this paper, a predictive model with the slopes displacement time sequence is established based on the phase space reconstruction theory, where the parameter of the predictive model is obtained by the minimum of prediction error method. The rationality of the evaluation index system is verified through the case studies.

Abstract: Through investigation and test analysis of current situation of testing stope and surrounding filling and isolation layer of mines, understand the basic mechanical characteristics and integrity characteristic of surrounding rock mass and fillings of chamber to be mined; combining with comparative analysis of technical and economic index of mining, considering making full use of the existing personnel, equipment and technology, it is concluded that stoping technology scheme of chamber is large-diameter deep-hole afterwards filling mining method; by using the numerical analysis method, through comprehensive analysis of stress, deformation and failure characteristics of surrounding fillings in mining, finally determine the optimal recovery scheme is mining by recovery unit of upper and lower plate. At present the ore block has been successfully and safely mined. Research results can provide reference for recovery of similar ore block, in order to realize safe and efficient recovery of "island" ore block in mining with filling mining method.

Abstract: In the mining process, if the roof is very hard, it will hang in a large area in the gob. The hanging roof may cave suddenly, which will crash the mining face and generate hurricanes so as to cause casualties and equipment damage. The hard roof control technology has mainly been used in the longwall mining face in coal mines for a long time, and made little use in shortwall mining face. The factors of roof caving is analyzed in shortwall mining area, which mainly consists of the coal pillar size and layout, the length of coal face, roof thickness and strength, the overburden load, the supporting conditions of roof and so on and the relationship of the factor and the limit caving area is studied. And then a new integrated control technology system is put forward, which includes: support and isolation by coal pillars, roof caving pressure relief, monitoring and early warning of roof fall, gob sealing by the stopping walls, and the principle of different technology and the parameter selection method is claimed. This technology is applied in Shangwan Mine of Shendong Group in China and the results shows that the hard roof caves naturally in small area, the hidden danger of large-area roof caving is eliminated completely, so the coal production is guaranteed to be safe.

Abstract: The 5204 transport roadway roof displacement encountered during the tunneling and mining is more than 240mm, which severely damaged the shape of the roadway. The anchor cable of the top is pulled off and supporting failure takes place. According to the analysis of the surrounding rock pressure behavior law, the concept of supporting new technology based on the concept of "coordinating role of long bolt - surrounding rock" is brought up. This technology can achieve a reasonable match of the supporting object with the displacement and support strength of the surrounding rock. Based on this concept, FLAC3D numerical simulation analysis, combined with the engineering analogy method, produces the long bolting parameters on the 5402 transport roadway. The industrial test results show that in the mining face, the force state of the long bolt is good. When larger displacement in the roof appears, the long bolt is not pulled off and the support failure does not occurs .It means the long bolt has adapted the large deformation of the roadway roof. The research results can provide a reference for similar mechanized caving roadway supporting.

Abstract: Multiple regression analysis of coal industry technology innovation is done by using data of years 1990-2008. It is found that technology innovation crowding-out effect do exist at coal industry. It is also found that environmental regulation can motivate coal enterprises technology innovation by adding variable. So the conclusion is got that proper environmental regulation policy is good for coal enterprises to improve competitiveness. Porter Hypothesis is tested. Keywords: environmental regulation, technology innovation, coal enterprise, crowding-out effect, Porter hypothesis

Abstract: In order to study the mechanics of the deformation of the wall rock, the right roadway in Chengshan mining field, Jixi Mine was chosen to determine the physical property, micro-structure, ingredients, clay and the inner-relationships between these properties using scanning electron microscope (SEM) and theoretical analysis. For further understanding the deformation mechanics within the wall rock, hollow inclusion stress release method was used. At the end, mechanism of the wall rock in the deep was established and corresponding deformation control technology was discussed by numerical simulation.

Abstract: Most of the dust control models indicate the line-curtain air reaching the face is limited and does not extend. Lower air quantity at the face helps in containing and concentrating the dust close to the face where no occupations are present. Hence, effective use of hydraulic sprays and directing the face dust-laden air into the scrubber may improve dust control. In this paper, we put forward a field testing of the modified scrubber-modified continuous miner demonstrated significant improvements in visibility and dust and quartz reduction, as compared to what was achieved with the current scrubber-current continuous miner dust control system. This is unfavorable from methane dilution point of view but can be used to advantage for improved dust control.