Retaining gob-side entryways and the stability of gas drainage boreholes are two essential techniques in the co-extraction of coal and gas without entry pillars （CECGWEP）. However, retained entryways located in deep...Retaining gob-side entryways and the stability of gas drainage boreholes are two essential techniques in the co-extraction of coal and gas without entry pillars （CECGWEP）. However, retained entryways located in deep coal mines are hard to maintain, especially for constructing boreholes in confined spaces, owing to major deformations. Consequently, it is difficult to drill boreholes and maintain their stability, which therefore cannot guarantee the effectiveness of gas drainage. This paper presents three measures for conducting CECGWEP in deep mines on the basis of effective space in retained entryways for gas drainage, They are combinations of retaining roadways and face-lagging inclined boreholes, retaining roadways and face-advancing inclined boreholes, and retaining roadways and high return airway inclined boreholes. Several essential techniques are suggested to improve the maintenance of retained entryways and the stabilization of boreholes. For the particular cases considered in this study, two field trials have verified the latter two measures from the results obtained from the faces 1111（1） and 11112（1） in the Zhuji Mine. The results indicate that these models can effectively solve the problems in deep mines. The maximum gas drainage flow for a single hole can reach 8.1 m^3/min and the effective drainage distance can be extended up to 150 m or more.展开更多
By analyzing the flow character of a single drainage borehole in its effectingtime and the correlative theory introduced,the reason for 'inflexion' appearance in theflow character curve of the single draining ...By analyzing the flow character of a single drainage borehole in its effectingtime and the correlative theory introduced,the reason for 'inflexion' appearance in theflow character curve of the single draining borehole in a multi-borehole was studied.Takingthe theory of permeation fluid mechanics and so on as basis,the coalbed gas flowmodel was set up,and the numerical simulation analyzer was built for undermine gasproducts.With the results from the analyzer,the gas capacity could be calculated underdifferent conditions and comparisons made with the site measurement data.展开更多
基金Acknowledgments The research was supported by Program for Changjiang Scholars and Innovative Research Team in University （IRT_I4R55）, and the National Natural Science Foundation of China under Grant No. NSFC-51274193.
文摘Retaining gob-side entryways and the stability of gas drainage boreholes are two essential techniques in the co-extraction of coal and gas without entry pillars （CECGWEP）. However, retained entryways located in deep coal mines are hard to maintain, especially for constructing boreholes in confined spaces, owing to major deformations. Consequently, it is difficult to drill boreholes and maintain their stability, which therefore cannot guarantee the effectiveness of gas drainage. This paper presents three measures for conducting CECGWEP in deep mines on the basis of effective space in retained entryways for gas drainage, They are combinations of retaining roadways and face-lagging inclined boreholes, retaining roadways and face-advancing inclined boreholes, and retaining roadways and high return airway inclined boreholes. Several essential techniques are suggested to improve the maintenance of retained entryways and the stabilization of boreholes. For the particular cases considered in this study, two field trials have verified the latter two measures from the results obtained from the faces 1111（1） and 11112（1） in the Zhuji Mine. The results indicate that these models can effectively solve the problems in deep mines. The maximum gas drainage flow for a single hole can reach 8.1 m^3/min and the effective drainage distance can be extended up to 150 m or more.
文摘By analyzing the flow character of a single drainage borehole in its effectingtime and the correlative theory introduced,the reason for 'inflexion' appearance in theflow character curve of the single draining borehole in a multi-borehole was studied.Takingthe theory of permeation fluid mechanics and so on as basis,the coalbed gas flowmodel was set up,and the numerical simulation analyzer was built for undermine gasproducts.With the results from the analyzer,the gas capacity could be calculated underdifferent conditions and comparisons made with the site measurement data.
