Abstract: Underwater pipelines connected to at least one point on a coastline are constructed by means of a pipelaying vessel associated with an independent underwater vehicle mounted on caterpillar-tracks and capable of traveling along the sea bed. From within the vehicle, pipe sections can be assembled and rejected as the vehicle moves forward. The pipe sections pass through a wall of the vehicle and into the sea, through a port which is provided with a plurality of inflatable annular sealing rings that selectively sealingly bear against the exterior of the pipeline. One of these sealing rings is associated with an annular piston, and a jack acts between this piston and the vehicle to provide the propulsive force for ejecting the pipe sections from the vehicle. Potential applications include mining operations, off-shore installations and intercontinental tunnels.

Abstract: The method consists in boring a shaft in the sea floor to form a drilling station of sufficient size to accommodate personnel and equipment, in lining the shaft walls with a casing which is cemented against the walls and surmounted by a water-tight self-contained subsea chamber, in extracting sea water from the shaft, in maintaining atmospheric pressure within the shaft and the subsea chamber, in lowering personnel and drilling equipment into the shaft and in carrying out drilling operations from the bottom of the shaft.

Abstract: An advancing support for providing a continuous propping, particularly for providing a continuous propping of mine galleries or like passageways, comprising at least two carriages for articulated tracks, each of said carriages including a beam having rounded ends and an articulated track closely surrounding the beam mounted for sliding friction on the beam, each of said beams being divided into spaced-apart longitudinal elements, a connecting element pivotally attached to each of said longitudinal elements for joining them together, said carriages being disposed one above the other to be applied respectively against the floor and roof of a gallery; at least one jack attached to the connecting element of the upper carriage and the connecting element of the lower carriage thereby joining said carriages together.

Abstract: A roof support capable of being moved by a drive mechanism while under permanent load includes two pairs of carriages, each carriage carrying an articulated track. The carriages of each pair are arranged one above the other and the two pairs of carriages are disposed parallel. The upper carriages can then be applied against the roof and the lower carriages against the floor of an underground gallery. The upper carriages are connected by at least one cross-member and the lower carriages are connected by two cross-members, and means are arranged to apply a force to the cross-members to separate the upper carriages from the lower carriages. The cross-members and carriages are connected together by pivotal joints.