Abstract: A method of producing structural supports for use particularly in mining applications includes the use of a relatively rigid and cylindrical shell casing. The shell casing is separable along the plane parallel to its axis, has open ends and is closed about a fabric tube which is axially supported therein. The fabric tube is filled with pressurized liquid building materials such as concrete. Once filled within the casing, the pressure of the building material forces the liquid component thereof out of the tube laterally and through perforations provided in the shell casing to drain the liquid away from the building material in the tube. The casing and tube are of size such that the remaining building material, which will constitute a pillar, extends completely between the surfaces it is to separate and support.

Abstract: A rotary cutter for gouging out ore from mine faces has an annular front section with a set of bits which cut a ring-shaped groove into the mine face when the cutter is rotated and moved forwardly toward and into the mine face, and a rear section which is surrounded by the annular section and carries a second set of bits which comminute the core within the ring-shaped groove. The rear section has a conical bottom wall for the respective bits and a cylindrical wall surrounding and extending forwardly of the conical wall. The cylindrical wall has outlets for evacuation of comminuted material of the core. Such comminuted material is discharged into spaces between the cylindrical wall and sickle-shaped arcuate supports which carry additional bits and slope rearwardly and outwardly, as considered in the direction of rotation and forward movement of the cutter.