During the roadway drifting in the Maokou limestone, often happen gas emissions, occasionally have karstic gas blowouts or outbursts, even coal-and-gas outbursts. Countermeasures should be studied to eliminate coal-and-gas outburst and karstic gas blow-out. Through studies on source, reservoir and capping bed condition of Maokou limestone, paleokarst landform, gas source and gas res-ervoir features, analyzed typical gas accident characteristics and summarized frequency of fissure gas overruns in different horizons. Then put forward countermeasures of rational horizon selection, gas blowout and outburst prevention measures, karstic fissures and caves survey and control, drilling blowout prevention device modification, geophysical prospecting accuracy improvement and predic-tion, forecast strengthening. Main haulage roadway, main return way, substation and sump should be arranged below 30m of Maokou Formation top surface. Special purpose Maokou gas drainage way should be arranged within 10~20m range apart from coal measures. After strict survey and control measures adopted, can eradicate karst cave gas outburst, coal-and-gas outburst;to use drills with auto-matically shut and stop high pressure gas orifice can control karstic gas blowout.%在茅口灰岩中掘进巷道时,常有瓦斯涌出、偶有岩溶瓦斯喷出或突出及煤与瓦斯突出.通过研究茅口灰岩的生成、储存和盖层条件、古岩溶地貌、瓦斯来源、瓦斯储集特征,分析瓦斯典型事故特征,总结不同层位裂隙瓦斯超限的频率.提出了合理选择层位、采取防范瓦斯喷出突出措施、探测控制岩溶缝洞、改进钻机防喷装置、提高物探准确率、加强预测预报等对策措施.集中运输大巷、回风大巷、变电所、水仓宜布置在茅口组顶部30 m以下;专用茅口瓦斯抽采巷宜布置在距煤系10~20 m;采取严密的探测控制措施后,可杜绝溶洞瓦斯突出、煤与瓦斯突出,采用能够闭锁自动阻止高压瓦斯喷孔的钻机可控制岩溶瓦斯喷出.
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