Device for closing off a mine gallery especially for use to prevent spreading of underground explosions

A device for closing off a mine gallery, especially for use to prevent spread of underground explosions, comprising a inflatable bag of flexible substantially airtight material and movable from a collapsed to an inflated position, said bag having in said inflated position a substantially cylindrical peripheral surface engaging an inner peripheral surface of the mine gallery and opposite curved end faces extending across the mine gallery, said peripheral surface having substantially midway between said end faces an annular constriction;

• a hardenable material filling, in said inflated position, the interior of said bag and said annular constriction so that the material in said annular constriction provides a seal and interlock between said bag and the surrounding face of the mine gallery;
• first conduit means communicating with the interior of the bag to inflate the latter first with a gas under pressure and subsequently with said material while the same second conduit means communicating with the interior of said annular constriction to fill the latter with said material while the same is in flowable and still unhardened condition;
• and at least one overpressure valve in an uppermost portion of the inflated bag to discharge the pressure gas during filling the bag with said hardenable material.