Theoretic Study On Determination Of Coal's Apparent Density

Cross-cut coal uncovering most likely to lead to outburst, and it's the most prominent risk in outburst. When we want to analyse the outburst risk with the application of the methods of the energy the initial releasing gas, we must guarantee the accurate determination of apparent density. Therefore, this paper does extensive experiments on outburst coal's apparent density. We use some method. Such as theoretical analysis on apparent density test, study on current determination of apparent density, and we seek to increase our research on some new methods in order to test apparent density.This paper puts forward certain simplifications and hypothesis based on analysis research of outburst coal's formation and structural characteristics, and we presented theoretical derivation and analysis. Analysis indicates that the outburst coal's apparent density decreases continuously with selecting grain size of experiments increasing.There are two current methods of apparent density. Such as determination method of pebble apparent density and determination method of coal's apparent density(GB/T6949-1998).We analysis them with proposed standards of determination experiment, and search the advantages and disadvantages of determination.This paper puts forward the experiment scheme of coal seam method and mensuration process. We design and produce coal seam simulator. We conduct the experiment of outburst coal, and analysis on results. Experiment results are not satisfactory, but this method opens a line of our thought. There is a certain sense to experimental study.With the fundamental nature of outburst coal, this paper uses ideal gas equation of state for the theoretical foundation, establishing the law of ideal gas equation of state for the experiment plan of prominent coal's apparent density determination, which standardize the selection of sealing material, the choice of determination instrument, the selection of carrier gas for experimental and so on. First, the experimental steps have been designed with the actual situation of the law of ideal gas equation of state. Second, we select the sealing material, and examination the accuracy of instrument with density determination of the steel ball, etc. Finally the apparent density of five coal samples that is outburst or suspicion was measured, then by carrying evaluation criteria, such as theory rationality, experimental plan utility, test results'stability and duplication, on the experimental plan analysis. It comes to the conclusion that the law of ideal gas equation of state for the experiment plan is extremely high in the usability and the accuracy.We obtained conclusion that the apparent density determination result of outburst coal is a function equation that along with particle size used in the experimental by fitting the test result by using the mathematical software Maple10.0. It accords with ours theory derivative. Simultaneously counter-view the test result of coal seam method, which cause that this method may utilize in the apparent density determination of big piece coal seam, not suitable in the experiment of the initial expansion energy release of gas.