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但在煤礦生產(chǎn)中卻經(jīng)常是遇到天然焦因瓦斯增大而中止生產(chǎn)的現(xiàn)象時(shí)有發(fā)生.But during coal mining, often stop production because of gas content in natural coke increase....

“天然焦”的英語可以翻譯為：dandered coal，blind coal，burnt coal，natural coke ...