A coal mining method with a combination of a slicing and caving, a double benefit in control of water conducted crack zone development and in reduction of coal production cost can be obtained.
对厚煤层采用分层与放顶煤相结合的采煤方法,既可控制导水裂缝带的发育高度,又可降低生产成本。
Through the analysis of material and construction, the dissimilar steel gear is successfully welded using stress reduction zone by heating and proper assemble and welding sequence.
通过对铸焊齿轮的材料和结构的分析,利用“加热减应区”法及适当的装配焊接顺序,成功地焊接了异种金属的合金钢齿轮。
Epigenetically oxidized sandstone bodies are widespread in the study area and at the front of the oxidation zone the reduction barrier exists.
区内普遍发育次生氧化砂体,其前缘存在还原障。
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