Abstract: It is proposed to construct a large diameter subsea bore hole (e.g. about 10 to 50 meters in diameter) provided with a stable wall by a method which comprises drilling a number of bore holes around the circumference of a ring of large diameter, supplying to the ring bore holes material to locally stabilize the surrounding geologic formations, and forming a central bore hole, or shaft, within the perimeter of the ring by drilling and reaming or by excavation. The ring bore holes and locally stabilized geologic formations form a stable wall of large diameter for the central bore hole shaft. It is contemplated that a large diameter subsea bore hole of the type described above could be used for the safe emplacement and disposal beneath the seabed of a large waste job object such as the shielded reactor core of a decommissioned nuclear submarine, or of other waste objects containing radioactive material.