Abstract: The invention relates to a probe assembly (1) adapted to penetrate and travel in a mass of material, comprising:a hull,a front striking zone (3) and/or a rear striking zone (4) axially opposite, for transmitting pulses to the hull,a striking piston (2) anda pneumatic motor for setting in motion the striking piston (2) so as to project it against a striking zone (3, 4) integral with the hull, a compressed-air supply for the motor, characterized by the fact that the friction of the hull and any guiding elements rigidly connected to the hull in a pulverulent mass is between a lower value f insufficient to assure the holding of the probe upon the recoil of the striking piston (2) and a higher value F preventing the probe from advancing upon the impact of the striking piston (2) on the striking zone (3, 4) so as to permit the advancement of the probe in the pulverulent material.

Abstract: The subject matter of the present invention is a method for the deployment of a duct within a mass of powder-like material, according to which the duct is deployed from a compact configuration, characterized by the fact that the duct is brought in this compact configuration to a point in the mass of powder-like material and, while one end of the duct is held fixed, the other end is moved toward the exterior of the mass of powder-like material, the deployment of the duct thus being effected.