Research on fine design method of pre-drainage zoning borehole on high gas working face
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摘要: 现有高瓦斯工作面一般采用单一钻孔间距预抽瓦斯,在预抽钻孔设计时未考虑地质构造等因素对设计抽采区域的影响,且未精确分析抽采达标条件下抽采时间与钻孔间距的相互关系,对工作面回采区域预抽设计没有实现分级、分区的精细化设计。针对以上问题,以霍尔辛赫煤矿3603工作面为研究对象,提出了一种高瓦斯工作面预抽分区钻孔精细化设计方法,改变了以往工作面从终采线到开切眼单一钻孔间距的粗放设计模式。首先根据工作面地质条件对其进行预抽区域划分,由回采计划确定各分区的抽采时间,然后根据不同抽采率条件下抽采时间与钻孔间距之间的数值关系确定各分区的预抽钻孔间距,实现预抽区域精细化设计。现场试验结果表明,相比原设计,钻孔抽采时间由原来的8个月降低至6个月,钻孔工程量由319 440 m缩减为154 960 m;观测期间整个工作面瓦斯体积分数未超过0.58%,且无超限现象。Abstract: At present, single borehole spacing is generally used to pre-drainage gas on high gas working face. But in the design of pre-drainage boreholes, influence of geological structure and other factors on the design of pre-drainage area are not considered, and relationship between extraction time and borehole spacing is also not accurately analyzed under condition of drainage standards. As a result, pre-drainage design of mining area on working face has not realized fine design of classification and zoning. For the above problems,taking 3603 working face of Huoerxinhe Coal Mine as research object, a fine design method of pre-drainage zoning borehole on high gas working face was proposed, which changes the extensive design mode of single borehole spacing from final line to open-off cut. Firstly, according to the geological conditions of the working face, the pre-drainage area is divided, and the extraction time of each area is determined by mining plan. Then, the pre-drainage hole spacing of each zoning area is determined according to the numerical relationship between the extraction time and the borehole spacing under different extraction rates, so as to realize the fine design of the pre-drainage area. The field test results show that compared with the original design, extraction time is reduced from 8 months to 6 months, and borehole engineering quantity is reduced from 319 440 m to 154 960 m; during observation period, the volume fraction of gas concentration on the whole working face does not exceed 0.58%, and there is no over-limit phenomenon.
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Key words:
- coal mining /
- high gas working face /
- gas pre-drainage /
- pre-drainage zoning /
- borehole spacing /
- fine desig
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