Abstract: A process for establishing a clear, generally horizontal borehole path in a subterranean formation includes drilling a generally horizontal borehole using a drill pipe, drill bit and an uphole drilling device and lubricating the drill bit and pipe by pumping a mud down the center of the drill pipe in sufficient quantity to carry cuttings, created by the drilling, from the horizontal borehole using a mud capable of creating a cake on the borehole wall. Throughout drilling of the borehole, the total solids content of the efflux is adjusted to preselected levels and recirculated through the drill pipe to continually create the borehole wall cake. After drilling, the drill bit and drill rod are removed and the drilling bit replaced with a casing shoe. Thereafter, the drill pipe is reinserted into the borehole with a liner therein.

Abstract: A process is provided for sealing a degas hole in a coal seam prior to mining of the coal therein which includes the steps of inserting a perforated liner into the degas hole substantially the entire length thereof and pumping grout down the center of the perforated liner to the end of the degas hole. As the end of the degas hole is filled with grout, pressure is increased to force grout through the perforations in the liner to fill the degas hole along the entire length thereof. The perforated liner is also useful in the election of methane gas prior to sealing of the degas hole and further ensures a clear path through the degas hole so that sloughing, or caving, of the degas hole prior to grouting does not interfere with the complete sealing of the degas hole.