extraction n. 1.抽出,拔出。 2.【化學(xué)】提取(法);萃取(法);回收物,提出物;精煉。 3.精選,摘要。 4.血統(tǒng),家世,出身。 5.【數(shù)學(xué)】開方,求根。 spirit of the first extraction 原汁酒。 a man of foreign extraction 外國(血統(tǒng)的)人。 extractions from a book 一本書的內(nèi)容摘錄。 an extraction of 81 percent 百分之八十一的出粉率,八一粉。 the extraction of root 【數(shù)學(xué)】開方法,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 針對大傾角煤層長壁炮采、落垛等采煤方法,存在回采率較低、員工勞動強(qiáng)度大、高產(chǎn)高效受限及安全等諸多問題,開灤(集團(tuán))趙各莊礦業(yè)分公司在探討大傾角煤層采煤工藝的改革及實(shí)踐大傾角煤層綜合機(jī)械化采煤過程中,取得了較好的社會經(jīng)濟(jì)效益。