英语翻译Underground mining and water resource effectsUnderground

英语翻译
Underground mining and water resource effects
Underground coal mining is conducted in seven Virginia
counties:Buchanan,Dickenson,Lee,Russell,Scott,Taze-
Environmental Geology 29 (1/2) January 1997 7 Q Springer-Verlag
well,and Wise.Underground mining methods fall into two categories:partial extraction,and high-extraction.Partial extraction (room-and-pillar) mining generally re- covers up to 50–65% of the mineable coal.Pillars of coal are left to support the roof.Subsidence occurs slowly over (decades to centuries) as support pillars crumble and roof collapse occurs.
Two different types of high-extraction mining are con- ducted in Virginia.Pillar-retreat mining is a variation of the room-and-pillar method,where the mine is developed in similar fashion.However,once the mine works have been fully developed,the pillars are mined as the opera- tion retreats back towards the mine entrance.The meth- od allows 70% or more of the coal to be removed,leav- ing the roof essentially unsupported.Longwall mining re- moves all the coal from one or more “panels,” each of which can be up to 300 m in width and a 1000 m (or more) in length.High-extraction methods remove most or all of the coal seam within mined areas,leaving the overlying rock (or overburden) unsupported.The resul- tant collapse of the overburden can affect overlying aquifers.

地下开采和水资源的影响
地下采煤是进行了7维吉尼亚州
县：布坎南,狄金森,李,罗素,斯科特,taze -
环境地质29 （ 1 / 2 ） 1月一九九七七q施普林格出版社出版
那么,和明智的.地下采矿方法分为两类：部分提取,高的提取.部分提取物（房柱式）采矿一般转口涵盖多达50 ¨ c65 ％的可开采煤炭.支柱的煤炭是左支持屋顶.沉降发生缓慢（几十年的世纪） ,作为支持的支柱崩溃和屋顶发生倒塌.
两种不同类型的高提取采矿协商冲压在维吉尼亚州.支柱撤退采矿是一个变异的房柱式方法,如煤矿,是发达国家以类似的方式.但是,一旦矿山工程已全面发展,支柱雷区作为歌剧的原因,务虚会回到对矿井的入口.该安非他命-外径允许70 ％或以上的煤被遣送离境,叶片-荷兰屋顶基本上是不受支持.长壁开采重新举动,所有煤炭由一个或多个°面板,±其中每个可高达300米的宽度和一千米（或以上）的长度.高提取方法除去大部分或全部的煤层内的雷区,离开覆岩（或覆盖）不受支持.该结果- tant崩溃覆可以影响覆含水层.