Advanced Materials Research Vols. 807-809

Abstract: A larger resulfurization took place in converter steelmaking using semi-steel from vanadium-containing molten iron pretreatment as hot metal in the Xichang Steel and Vanadium plant, which results in a serious impact on the improvement and qualified rate of a variety of high quality clean steels production. On the problems were present at the process of vanadium containing hot melt pretreatment, some production process optimization tests and process comparative analysis were carried out. The results showed that: resulfurization results in a difficult control of sulfur content in molten steel in course of vanadium recovery via BOF operation for the first desulfurization next vanadium recovery that is suitable for the production of normal sulfur steels. The first vanadium recovery next desulfurization is in more favor of slag skimming and low iron loss, which is suitable for the production of low sulfur steels. The production costs of the latter reduce 15 to 22 yuan / ton steel than the former, on the basis of cost comparison of plain steels and low sulfur steels, respectively.

Abstract: The principle of roadway layout is in the low stress zone. Roadway will be difficult to support due to the lower seam face in the close multi-seam is affected by dynamic pressure of the upper seam face mining. The distribution of abutment pressure after the upper seam face mining were analyzed,concluded that: The layout of lower seam roadway should avoid the stress concentration area of residual coal pillar; Stress concentration of the coal pillar is related with mining order, and stress concentration degree is higher in the first mining side of the coal pillar; when the upper coal seam is gob, the layout of the roadway in the lower coal seam with the pattern of homodromous alternate interior layout will be easy to support.

Abstract: Under uniaxial compression loading, the failure experiments of plastic and brittle coal are carried out to study the acoustic emission evolution characteristic. The results show that the evolution of acoustic emission during the coal failure process corresponds with the process of coal crack initiation, propagation and coalescence. The acoustic emission event rate of the typical plastic coal displayed the variation of up-peak-down during the failure process. The event rate of acoustic emission increase sharply and then drop steadily is the precursor that the main crack plane of the plastic coal would coalescence and the coal will lose its stability. During the failure process of typical brittle coal, the event rate increased steadily with the increase of stress, showing the variation of up-peak; the down stage of acoustic emission is not obvious because the brittle coal suddenly fail after stress peak. The study results can provide a theoretical basis for explanations of the variation of acoustic emission and the establishment of instability criteria in coal and rock stability monitoring engineering by AE technology.

Abstract: In the process of deep mining, mining roadway has severe deformation and high deformation speed. Arranging mining roadway is an effective way to reduce deep roadway deformation under the mined-out area. This paper uses FLAC^3D Fast Lagrangian Analysis of Continua to make the coal rock geological structure modeling, works out the stress and strain state of coal and rock in different ways when arrange mining roadway under goaf, and then get the influence rule by comparing and analyzing the computed result, providing reliable and efficient theoretical foundation for arranging mining roadway under goaf.

Abstract: The simulation of natural evaporation process of Longmucuo brine in winter was conducted in laboratory, and the original brine was preliminarily concentrated in field. The crystallization sequence of salts, enrichment rule of boron and lithium were obtained. The crystallization sequence of salts of this brine is similar to that of Da Qaidam brine in winter. The boron is enriched in concentrated brine at the same concentration factor with the brine. The concentration factor of lithium is the same as that of the brine at the early evaporating process before the brine is concentrated to 4 times, and it is much lower than that of the brine because of the crystallization of lithium in the late process.

Abstract: With the analysis of key elements on the strain state of coal, a permeability dynamic prediction model which is divided by the critical desorption pressure for undersaturated coalbed methane (CBM) reservoirs was established on the basis of pore pressure and considering the matrix shrinkage effect of coal. The law between permeability and pore pressure was analyzed during production with the new model. Through case study, the rationality of the model was also verified. The research shows that the degree of permeability changes mainly depends on the relationship between the critical desorption pressure and the rebound pressure which depends on the strength of the matrix shrinkage. Under the condition of equivalent matrix shrinkage, the reservoirs permeability rebounds better with high Young's modulus and low Poisson's ratio. Adjustment factor contributes to improve the influence of matrix shrinkage on permeability and the larger the matrix shrinkage strength is, the higher the permeability rebounds. PM model and CB model are similar to the new model. PM model limits the matrix shrinkage strength, and CB model is a special case of the new model. Comparing with the well test permeability, the new model is more reasonable to characterize the matrix shrinkage effect in the development process.

Abstract: Aiming at overcoming the disadvantage of ignoring environment resources value loss caused by mineral resources exploitation in traditional GDP accounting, a new accounting method was put forward. Through analyzing the forms of environment damage caused by mineral resources development, the mine environment problem was divided into seven forms: natural landscape damage, vegetation destruction, geological disasters, air pollution, water pollution, solid waste pollution and noise pollution. Based on this classification system and general principle of value estimate for environment resources, the value loss indexes of each form were identified, and the calculation method for every index was put forward. As a result of the research, an accounting model that can be used for green GDP accounting relative to mineral resources exploitation was obtained.

Abstract: Taking raw coal of China as the investigation object, MIPS method was used to calculate the material input of raw coal in the period of 1990~2008. Numerical calculation indicated that, in the production of raw coal, water input accounted for above 72% of the total material input, and solid non-biological material input accounted for about 25%, while air input accounted for only 0.4%. As for the whole country, the average input coefficients for water, solid non-biological material, and air were 6.13 t/t, 2.13 t/t, and 0.03 t/t, respectively; the average input coefficients for water, solid non-biological material, and air were 6.07 t/t, 2.26 t/t, and 0.03 t/t, respectively, for the state-owned major coal mines; in the local mine, the average input coefficients for water, solid non-biological material, and air were 6.17 t/t, 2.03 t/t, and 0.03 t/t, respectively. The raw coal material input as a whole appeared to be rising.

Abstract: 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.

Abstract: This paper research on the failure mode of a coal mine dump slope in Inner Mongolia. Firstly, there are some brief introductions of the surface mine dump slope failure mode and the basic principles of Lagrangian; Secondly, the collected geological data is shown. We established the dump slope model by FLAC3D program and than draw conclusions. This method can provide an useful safety information for the opencast coal mine.