The mechanical model of key strata supported by coal pillar is set up according to the layout of coal pillars in the coalface of short wall mining.是什么意思_The mechanical model of key strata supported by coal pillar is set up according to the layout of coal pillars in the coalface of short wall mining.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句