The monitoring on underground coal bed combustion relied on drilling supervising in the past, but this method is not good.

对地下煤层燃烧过去一直依靠钻孔进行监测，未有有效的监测方法。

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Internal combustion engines used in machinery for underground works have been removed. They are not machinery, but partly completed machinery.

用于地下工作的机器里的内燃机已经删除了。它们不是机器，而是完整机械的一部分。

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The selection of combustion-chamber types of diesel-engines for underground mines is closely related to the performance of the engines themselves.

地下矿用柴油机的燃烧室型式与其主要性能有密切的关系。本文从废气排放、使用经济性以及噪音等方面对比了两类柴油机的优劣。

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The concept of heating underground coal to a combustion point may lead one to recall Centralia, PA, an abandoned town in Pennsylvania sitting on a coal seam which has been burning for 50 years, but the UCG controlled process makes that outcome highly unlikely.

FORBES: Underground Coal Gasification: A Trend Worth Watching