It is put forward that the top coal of low gaseous steep seam can be caved only when the top coal is in the limiting equilibrium state of stress under the abutment pressure.是什么意思_It is put forward that the top coal of low gaseous steep seam can be caved only when the top coal is in the limiting equilibrium state of stress under the abutment pressure.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句