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There has been quarrying in the area for centuries.
这地方的采石业已有几百年了。
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They were quarrying limestone.
他们在开采石灰石。
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They are quarrying in old manuscripts.
他们正在旧手稿中寻找资料。
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They are quarrying the hillside for marble.
他们正从山坡上采大理石。
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He spent much time in quarrying in old records.
他花了很多时间从旧记录中寻找资料。
露天开采,又称为露天采矿,是一个移走矿体上的覆盖物,得到所需矿物的过程,从敞露地表的采矿场采出有用矿物的过程。露天开采作业主要包括穿孔、爆破、采装、运输和排土等流程。按作业的连续性,可分为间断式、连续式和半连续式。 露天与地下开采相比,优点是资源利用充分、贫化率低,适于用大型机械施工,建矿快,产量大,劳动生产率高,成本低,劳动条件好,生产安全。