Applied Mechanics and Materials Vols. 522-524

Abstract: In order to analyze the stability of the gob roof, the RMR rock mass classification was used for rock quality evaluation to calculate the rock condition and the collapse possibility of the gob roof was proved by the results of the 3D FEM numerical analysis, thus took the-140m level as an example, the monitoring scheme for the gob roof movement was designed, then the time series prediction was analyzed for rock movement. Based on the results of predicting data, the rock movement value of the gob roof was increasing gradually, supporting scheme should be formulated to control the rock movement value.

Abstract: The paper focuses on coalmine safety investment, studies and summarizes theories of safety investment and real option. Based on real option applications on pricing, venture investment, investment decision, estimation and valuation, investment assessment and safety investment, it analyzes the problems in researches on coal mine safety investments and advantages of constructing pricing model that combined real option with fuzzy mathematics theory, and proposes research direction of incorporating fuzzy numbers into real option model.

Abstract: Assessment index system for safety capability of mine team leaders is established to assess their safety capability accurately, after defining its concept. The system is comprised of two layers, with 5 indexes in the first-layer and 14 indexes in the second-layer. Furthermore, the relative weights of indexes are determined by analytic hierarchy process (AHP). The grey relational assessment model for safety capability of mine team leader is constructed based on the indexes system. The safety capability of 4 mine team leaders are assessed by the model, according to the sequences in their safety capabilities. Assessment for safety capability based on AHP and GRA could be a tool for evaluation and decision-making in mining enterprises.

Abstract: According to the characteristics of the tunneling working face dust, the digging machine spray and airflow purifying water curtain linkage automatic spraying dust settling technology, improved the precipitator, research and application of high pressure spray technology, make the tunneling working surface has good dust fall effect, to ensure the workers health and safety in production of coal mine.

Abstract: In this paper, the leaching effect of zinc oxide ore was investigated using ammonium sulfate solution as leaching agent. The effects of temperature, concentration of ammonium sulfate, average particle size and stirring speed on the leaching of zinc oxide ore were studied. The leaching rate increased with increasing solution temperature, concentration, and stirring speed as well as with decreasing average particle size. Ammonium sulfate solution can therefore be used as an effective leaching agent for zinc extraction from zinc oxide ore.

Abstract: Sulfate roasting and dilute sulphuric acid leaching were applied to extract lithium from lepidolite. Several conditions including roasting temperature, roasting time, K₂SO₄ and CaO were investigated to improve the lithium extraction efficiency, the final lithium extraction efficiency could attain 94% with the conditions as follows: roasting temperature 850°C, roasting time 2 h, K₂SO₄ to lepidolite mass ratio 0.15 and CaO to lepidolite mass ratio 0.75.

Abstract: Floatation experimental research is carried out on a certain complicated ore containing mixed sulphides in Yannan province. For the characteristics of the mine and the scene of the test requirements, the use of mixed flotation-separation process has achieved a successful recovery of useful elements. Combination inhibitors can effectively achieve the separation of copper and sulfur .Under the proper process conditions ,the good technical indexes were obtained.

Abstract: In order to test the performance of a vibration lamella thickener, a ZXN32 was applied to a industry experiment.We carried out a series of experiment and measured the test parameter of the equipment which was based on particle size analysis and settlement experiment.The test results show that the calculation of the capacity meets with the practical capacity.The test equipment runs stably and compares with the thickener used in the plant,the test equipment is 2.7~2.8 times as much as thickener in capacity per unit area at the same conditions.

Abstract: Based on the analysis of the properties of a high carbon pyrite from Yunnan, a series tests on gravity concentration and flotation were carried out. According to this basis, a closed-circuit flotation test scheme was worked out, which obtained a fine quality pyrite concentrate with a sulfur grade of 38.24%, comprehensive sulfur recovery of 70.87% and carbon content of only 0.87%.

Abstract: The copper oxide ore is high oxidation ratio and the high combination ratio with a low grade of Cu 0.71%. Copper concentrate of Cu 15.02% with a recovery of 38.55% was obtained by flotation. The optimum acid leaching conditions were investigated. Effects of lixiviant concentration, solid-to-liquid ratio, leaching time were investigated. The acid leaching efficiency was 78.75% relative to flotation tailings. By the combination of flotation and acid leaching flotation tailings, most of the Cu in the minerals can be enriched, the total recovery of copper reached 86.85%.