Abstract: The present invention is directed to a method for breaking rock and other hard materials using small-charged blasting techniques followed by a mechanical impact breaker. In small-charge blasting techniques, a gas is released into the bottom of a sealed hole located at a free surface of the hard material. The gas pressure rises rapidly in the hole until the gas pressure causes the hard material to fracture. In one embodiment, the a deeper hole is drilled and/or a small amount of blasting agent is used to cause the formation of a network of subsurface fractures while either not removing any of the rock or removing the rock with very low energy flyrock. In another embodiment, only the central portion of the face is broken and/or removed by blasting. The impact breaker is then used to complete fracturing and removal of the material.

Abstract: A machine for removing slag and metal remainders from crucibles or casting ladles includes a frame on which is disposed a carriage movable in an upwardly inclined direction on guides or rails. The carriage is provided with cutter device having a tool head. A holder for a crucible is tiltable from a first position where the crucible can be placed on the holder to a second, operating position where the crucible is coaxial with the cutter device. The cutter is of the full profile type and is provided with a plurality of first tools which are spaced apart along the periphery of the tool head and second tools which are spaced apart in the radial direction on a front part of the tool head. The second tools are arranged so that the bottom of the crucible will be cleaned completely. The tool head is provided with axial through holes for the transportation therethrough of slag and metal remainders.

Abstract: A crawler track mounted mining machine having a frame and an adjustable jib carrying an endless cutting chain having cutters and loading flights mounted on the frame. A bridge on the frame and spaced arms having one end pivotally connected to the bridge and the other end supporting a front plate upon which the jib is adjustably mounted by a rotatable bearing supporting a cross member which carries hinges pivotally supporting the jib. Hydraulic rams extend between the cross member and the jib to rotate the jib between a vertical position and a horizontal position and a hydraulic ram extends between the rotatable bearing and the front plate to rotate the front plate and the jib in a horizontal plane between a position perpendicular to the crawler tracks and a position parallel to the crawler tracks. Hydraulic rams extend between the bridge and the arms to raise and lower the arms and the jib relative to the frame.

Abstract: A hard compact material, such as rock, is broken by driving a longish mass body of relatively incompressible fluid, such as water, against the material to be broken. The mass body is caused to impact the material at a momentum required for breaking the material. The required momentum is obtained by adding the momentum of at least two fluid mass bodies. The longish mass body can be aligned with a drill hole by means of the drill bit and rod. The energy generator or fluid gun and the gun barrel can be made in separable units.

Abstract: Apparatus for guying a movable cutting machine equipped with a caterpillar drive and for moving the machine on ascending galleries has at both sides of the cutting machine tension members formed of chains or ropes and led over winches. The tension members are adapted to be fixed on both sides of the cutting machine, with the forward ends and the rearward ends of the tension members being adapted to be fixed at stationary locations of the gallery, preferably by means of rock anchors.

Abstract: 1. A method of inducing rapid failure in a shape that is under stress and is composed of cold rolled steel comprising applying against a surface of said cold rolled steel shape a mixture composed of lithium metal, lithium chloride and potassium chloride, rapidly heating that mixture as well as the surface of the steel shape in contact therewith sufficiently to melt the mixture but below the annealing temperature of the steel, and maintaining that temperature until the steel shape cracks.