Abstract: Producing a fracture network in deep rock, e.g., in an ore body, by detonating explosive charges sequentially in separate cavities therein, the detonations producing a cluster of overlapping fracture zones and each detonation occurring after liquid has entered the fracture zones produced by previous adjacent detonations. High permeability is maintained in an explosively fractured segment of rock by flushing the fractured rock with liquid, i.e., by sweeping liquid through the fracture zones with high-pressure gas, between sequential detonations therein so as to entrain and remove fines therefrom. Ore bodies prepared by the blast/flush process with the blasting carried out in substantially vertical, optionally chambered, drilled shot holes can be leached in situ via a number of holes previously used as injection holes in the flushing procedure and a number of holes which are preserved upper portions of the shot holes used in the detonation process.

Abstract: Explosive cartridges are loaded into boreholes at a rapid rate by guided descent through a retractable flexible tubing assembly through which a stream of water flows. The cartridges preferably are cut open just before their discharge from the assembly, and their passage through, or discharge from, the assembly is detected outside the borehole. The assembly is retracted incrementally until completion of the loading. Apparatus comprising a cartridge-guiding assembly through which a stream of water flows, and means associated with the assembly for sensing cartridge passage or discharge.

Abstract: Directed thrusts are generated in rock by detonating explosive charges in groups of drill holes therein, the drill holes being aligned so that the maximum thrust from the substantially simultaneous detonation of charges in a group of holes is exerted in a direction close to one in which the rock has been found to be particularly vulnerable to failure, i.e., a direction that is at an angle of 60.degree. to a representative normal of a densely populated set of joints in the rock and that also is close to a direction of maximum principal tectonic stress should one be found.