Predegassing of Coal Seams in German Hard Coal Mines
- 作者：Erwin Kunz
- 会议时间：2007-10-25
- 关键词：gas ; coal outbursts ; Hard Coal Mines ; Predegassing of Coal Seams
- 作者单位：DMT GmbH,Germany
- 母体文献：2007中国(淮南)煤矿瓦斯治理技术国际会议论文集
- 会议名称：2007中国(淮南)煤矿瓦斯治理技术国际会议
- 会议地点：安徽淮南
- 主办单位：中国煤炭学会
- 语种：chi
摘要
Decrease of the gas content in the worked seam by degassing before the start of winning has proven its worth in some areas of German hard coal mines,on the one hand in order to remove the risk of gas/coal outbursts and on the other hand in order to reduce the gas inflow into the longwall.The underground experiences of the last 30 years have led to a“hit list”of coal seams with respect to their suitability of predegassing.Trials in the DMT-laboratory and also results gained in the deposit show that the suitability of a seam for predegassing depends on its rank.In seams with volatile matter of 20%~30%,high efficiency ratings are achieved as a rule,with lower ratings both in seams with lower and with higher content of volatile matter.If the rock pressure is unusually high,the efficiency rating of the predegassing is lower,even in seams which would normally be suitable for this process.Under unfavourable conditions,for example below or above residual pillars,in-seam boreholes cannot be drilled successfully and the method is not practicable.But if the worked seam was already stress relieved,the predegassing has an optimal efficiency.Latast investigations show,that the distance of the in-seam boreholes from one another can be extended.But in that case the time,which is necessary to reach the same reduction of the gas content,increases considerably.