An electric-pulse fracturing device for hard roof of coal mine based on a self-sealing water bag and an using method thereof are provided. The device includes a power switch, a charging power supply, a current limiting protection resistor, an energy storage capacitor and a high-voltage electric pulse switch connected in sequence. The energy storage capacitor is connected with an end of a gas gap switch, an other end of the gas gap switch is connected with an assembled self-sealing water bag high-voltage electric pulse electrode structure through a high-voltage cable, and the electrode structure is fixed through an assembly rod. The self-sealing water bag high-voltage electric pulse electrode structure includes a self-sealing water bag and an electrode structure capable of focusing shock wave energy, and the number of the self-sealing water bag high-voltage electric pulse electrode structure depends on fracturing effect.

A system for excavating a rock face using microwaves. The system may include a microwave generator, an articulable robotic arm with a plurality of rotatably connected rigid waveguide segments, an applicator attached to a distal end of the robotic arm, and a robotic control system. The system produces microwaves with the microwave generator and moves the robotic arm such that the applicator moves along the rock face as the microwaves exit the applicator to precondition the rock face for excavation. Various patterns of microwave treatment, and controls based on sensor feedback, may be implemented.