In the coal mining process, in order to ensure the safety of the working face and the stability of the roof, it is very important to arrange the main crack surfaces between the working face and the roof. Below is a common arrangement that can help reduce the risk of landing on the work surface roof. Figure-eight arrangement of spray holes
It is necessary to set up reasonably arranged spray holes on both sides of the working surface. These injection holes should be located on both sides of the working surface and arranged in a figure-eight shape with the main fracture surface. This arrangement can effectively prevent the expansion of crack surfaces and the collapse of the roof. Brackets and support devices
Support the roof of the working surface by properly setting up brackets and support devices. Various forms of support and reinforcement measures can be used when necessary, such as wooden column supports, metal supports, hydraulic supports, etc. These support devices should be reasonably arranged according to the condition of the roof to achieve effective support for the roof of the working surface. Composite support technology
For situations where there is a large suspended roof, composite support technology can be considered. This technology includes the comprehensive use of anchor cables, steel arches, shotcrete and other means to strengthen and support the roof of the working surface and prevent it from falling to the ground. Improve safety
In summary, rationally arranging the main crack surfaces between the working surface and the roof, and adopting appropriate support and reinforcement measures are the keys to ensuring that the roof of the working surface is not easy to fall to the ground. Such an arrangement can improve safety to a certain extent and protect workers' lives and property.