Underground formed wall single-entry mining method

Abstract

A method is provided for the underground mining of thin seams of certain minerals, such as coal, particularly minerals capable of being bored or cut, employing walls formed in place. A relatively narrow substantially rectangular drift is cut in the seam, usually the entire height of the ore formation. The drift is then filled with low-grade concrete to form a wall. After the concrete has set to have sufficient compressive strength to provide support for the overburden, additional drifts are driven immediately adjacent to the wall and are joined behind the wall, so as to allow for air circulation around the wall and provide space to repeat the process. In this way, a plurality of tandem walls can be introduced through the working area of the seam. Between each tandem wall, a temporary barrier is erected, having manways with closeable doors therein as required, so that forced ventilation will travel the full length of one drift and return back through the companion drift. Additional walls may be established at lateral distances from the first wall, so as to define an area of the seam for longwall mining. Desirably, the walls are of a compressible material. After removal of the mineral or coal between the walls, upon subsidence of the overburden, the walls will be substantially compacted, so as to minimize surface unevenness.