extraction n. 1.抽出,拔出。 2.【化学】提取(法);萃取(法);回收物,提出物;精炼。 3.精选,摘要。 4.血统,家世,出身。 5.【数学】开方,求根。 spirit of the first extraction 原汁酒。 a man of foreign extraction 外国(血统的)人。 extractions from a book 一本书的内容摘录。 an extraction of 81 percent 百分之八十一的出粉率,八一粉。 the extraction of root 【数学】开方法,求根法。
The conventional methods for mining such seams including the longwall blasting and block caving suffer form the drawbacks of being low in recovery , high in labor intensity and low in efficiency . after shifting to the use of the fully - mechanized extraction system by the zhaogezhuang branch mining industry co . of kailuan ( group ) co . , the mining of the pitching seams has met with remarkbable social and economic result 针对大倾角煤层长壁炮采、落垛等采煤方法,存在回采率较低、员工劳动强度大、高产高效受限及安全等诸多问题,开滦(集团)赵各庄矿业分公司在探讨大倾角煤层采煤工艺的改革及实践大倾角煤层综合机械化采煤过程中,取得了较好的社会经济效益。