Advanced Materials Research Vols. 1010-1012

Abstract: In order to backfill the west open-pit mine in Fushun which is abandoned soon, the key technology of chute process has been studied. According to the movement rules of materials in the chute, using the method of theoretical calculation and laboratory simulation , U chute with inclination angle of 33°has been determined, mathematical model of material transportation in the chute has been established, the distance and height of materials reaching the bottom of the chute has been determined and the protective wall with hight of 2 m, distance of 24 m to the chute has been designed. Meanwhile, by numerical simulations, rules of dust transportation and diffusion in the chute has been studied , dusts finer than 100µm has been identified as the main pollutants, and the chute process of dust-protected has been put forward .

Abstract: There are many factors which influence the slope stability. In order to analyze the degree of importance of each influence factor on slope stability, this paper establishes a slope stability analysis model based on BP neural network. The computation results showed that the model was reasonable and reliable. On this basis, the sensitivity of various influence factors to slope stability was analyzed by single-factor test, which were internal friction angle of rock, bulk density, pore pressure coefficient, slope angle, rock cohesion and slope height in a descending order of sensitivity.

Abstract: The gas concentration field in goaf of Huangling No.1 Mine 304 fully-mechanized face was simulated numerically by FLUENT software with high fracture drilling or not. The results of numerical simulation were confirmed by fixed sampling method of immersed tube in goaf. Thus, the law of gas concentration field was gained, which provides the important basis for gas control of working face.

Abstract: In order to master the law of ground surface movement and deformation for shallow buried and thick coal seam under condition of fully mechanized caving mining method, and to gain experience of “mining under buildings, water body and railway”, a ground surface movement observation station was established above 14106 and 14107 working face of No.1 Well which belongs to China Coal Pingshuo Group co., Ltd. Then a series of observation was conducted according to the requirements of relevant technology. After that, process of sorting, calculating, analysis was conducted based on the observation data. As a result, characteristics of surface movement and deformation under this mining and geological condition were mastered by author, the surface subsidence calculation parameters and some surface movement angle parameters was calculated. Based on analysis of ground depression velocity and deflection in the period of ground movement, it is concluded that shallow buried depth with fully mechanized caving mining method has a shorter ground movement active period than that of deep mine, at the same time, its maximum subsidence velocity is big, ground movement and deformation is strenuous and subsidence during ground movement active period occupies a huge proportion of the total subsidence.

Abstract: The design construction length of conveyance roadway of the mine working face is nearly 5000m and the section area of driving is 18m², belongs to large section super-long coal roadway. Through advanced mechanized supporting facilities tunneling construction and using reasonable support pattern and labor organization, it ensured the safety of workers, reduced the labor intensity, and realized the safety and rapid excavation with 440m/month. The economic and social benefit is obviously. It could provide reference meaning for other large section coal roadway rapid excavation at home and abroad.

Abstract: Rock bursts are serious threats to safety and production in coalmines, which are becoming more serious with the increase in mining intensity and depth. Electromagnetic radiation (EMR) always occurs along with coal rock deformation and fracture. EMR monitoring technique, the method using the short period changes of EMR signals before rock burst, has been widely applied to monitor and predict rock burst. This paper mainly studied the relationship of EMR generated by coal rock mass to applied loads and monitored the working face and roadways of coalmine by monitoring instrument, the results show that the EMR monitoring method has excellent performance in predicting rock burst.

Abstract: This article describes the basic process of numerical simulation, and an example of Xinyu coal mine roadway numerical simulation research. And the support scheme is proposed by the numerical simulation result.

Abstract: The copper activation mechanism of pyrite surface was simulated by density functional theory (DFT) method. It is shown that copper (Cu) can easily adsorb on pyrite surface, which causes the flotation of pyrite. The adsorbed Cu 3d orbital interacts with surface S 3p orbital forming covalent Cu-S bond. The charge of sulfur dimer increases and the adsorbed Cu is positively charged while the positive charge of surface Fe atom decreased, resulting in the surface capturing electrons from Cu.

Abstract: The Co- and Ni-bearing pyrite (100) surfaces were studied using density functional theory (DFT). The calculated results show that the covalency of the bonds on surface is weakened due to the presence of Co or Ni impurity, especially for the Ni-bearing pyrite surface. Hybridization occurs between Co 3d and S 3p and between Ni 3d and S 3p. The electrical conductivity of surface is enhanced due to the presence of Co and Ni impurities. Surface Co atom is predicted as spin-polarized and surface Ni atom is calculated as low-spin state.

Abstract: During the processing of iron ores, a large quantity of low-grade tailings containing abundant iron values in fine particle size range is produced. A novel HGMS-Centrifuge process is proposed to recover iron values from a low-grade hematite tailings. In this process, the tailings is effectively roughed with pulsating high pulsating high gradient magnetic separator to produce a relatively high-grade iron concentrate, then this concentrate is cleaned with a continuous centrifugal concentrator to produce a high-grade iron concentrate. The results of investigation indicate that this novel process is capable of producing an iron concentrate assaying 58.48% Fe with 21.66% recovery from the tailings assaying 28.12 % Fe. It was concluded that this novel process may be effectively used to recover iron values from low-grade hematite tailings.