精选优质文档-倾情为你奉上 The Improvement of the Mine Gas Drainage矿井中瓦斯抽排的改进Abstract：Effective gas management is vital to the success of the long wall mining in the Bull seam, in the Southern Coalfield, Sydney Basin, NSW, Australia. The evolution of gas drainage methods and practices are discussed with respect to gas type, gas drainage lead time and prevailing geological conditions.（本文就瓦斯气体类型，气体抽放前置时间和泛地质条件下的气体抽放方法和实践的进展进行了讨论。） Both underground to inseam drilling and surface to inseam d
