| Drainage gas, as a gas control method, is a high advanced method whose effect has been recognized and applied. However, high drilling still has some problems, such as the extraction effect is unstable, gas overrun occurs frequently when drilling field changing, gas concentration is too low to be used, few reference when new mine is designed. Problems above make it difficult to reach a high efficiency of gas extraction,and result in the decrease of the safety factor. Based on this problem, optimize the drainage of high drilling of Yangdong mine to reach a better effect.Methods of empirical formula, similar material simulation and numerical simulation and industrial test are used in the research. After the determination of basic parameters,right formula is chosen to preliminarily classify the height division of fractured zone, by using similar material simulation experiment, how the roof cave, and how the roof fall down are clearly to see, and by some other technical means stress changes when the model is mining are more obvious too, numerical simulation is used as a kind of access to make up the shortfall of the measured and the physical model to collect a large amounts of information in the process of overburden rock caving by effective means, because of the means of simulation are limited.Final height of high drilling hole is 22 ~ 52 m after analysis of the three kinds of means above, which is different from actual parameter 30~60m that yangdong mine is adapted, and then industrial test is used as the a way to determine which data is more accurate. The changes of indicators such as gas concentration, flow are observed in the process of gas being extraction through high drilling. Comparing the two results, the experimental results make a better control of the coal gas, it is helpful for the management and utilization of gas. So, experimental optimization should be taken seriously in the design of high drilling, and think less of the past experiences. |
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