Gas extraction by bedding boreholes is a key means to realize safe mining of coal mine and protect the environment. The traditional bedding boreholes are usually constructed in the center of the coal seam. which may not obtain a high methane extraction rate because of the existence of tectonic coal sublayer with low permeability. In this paper. https://trendingcustomes.shop/product-category/acrylic-ornament-custom-shape/