This method is able to show the characteristics of Datong direct roofs,also has guiding meaning for roof control practice. 這種方法，既能反映大同直接頂板的特點(diǎn)，又對頂板控制的實(shí)踐具有指導意義。
According to the studying and acquainting with the direct roof control of Datong mining area,this paper offers a kind of simple and workable classification for direct roofs. 根據作者對大同礦區直接頂板控制的研究和了解，提出了一種簡(jiǎn)單易行的直接頂分類(lèi)方法。
The outport bears the load of top-coal and breahs immediate roof. 支架承受的是上方煤體和折斷部分直接頂的載荷。
According to the studying and acquainting with the direct roof control of Datong mining area,this paper offers a kind of simple and workable classification for direct roofs. 根據作者對大同礦區直接頂板控制的研究和了解，提出了一種簡(jiǎn)單易行的直接頂分類(lèi)方法。
