This method is able to show the characteristics of Datong direct roofs,also has guiding meaning for roof control practice. 这种方法，既能反映大同直接顶板的特点，又对顶板控制的实践具有指导意义。
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. 根据作者对大同矿区直接顶板控制的研究和了解，提出了一种简单易行的直接顶分类方法。
The outport bears the load of top-coal and breahs immediate roof. 支架承受的是上方煤体和折断部分直接顶的载荷。
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. 根据作者对大同矿区直接顶板控制的研究和了解，提出了一种简单易行的直接顶分类方法。
