So it takes a lot of effovt for preventing coal spontaneous combustion in per year in coal mine methods are grout nitrogen flooding and even pressure fire-extinguished to prevent coal spontaneous combustion.是什么意思_So it takes a lot of effovt for preventing coal spontaneous combustion in per year in coal mine methods are grout nitrogen flooding and even pressure fire-extinguished to prevent coal spontaneous combustion.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句