Abstract: An inflatable borehole plug comprising an inflatable fluid tight bag with a storage container containing an inflation fluid in a compressed state located within the fluid tight bag. The storage container has a first actuator and a second actuator located at opposite ends thereof to initiate release of inflation fluid and hence effect expansion of the fluid tight bag. Choice of the vertical orientation of the first and second actuators and of which or both are activated provides differing rates of release of the inflation fluid and corresponding different rates of inflation of the fluid tight bag.

Abstract: A breech assembly similar to a modified shotgun breech is used to fire gaus combustion products from a shotgun type pyrotechnic cartridge into a tank that holds the compressed gas. This compressed gas can then be used to drive power tools, inflation assemblies or any device which normally operates on compressed air.

Abstract: An apparatus for breaking coal or other mineral matter from a bed thereof which comprises a string filling a bore hole which can rise steeply in this bed. The string consists of alternating breaking units and connecting pipes each braking unit having a differential piston displaced solely by the action of air pressure so that breaking slots are unblocked to discharge compressed air built up in the string. The pistons are provided with check valves to permit filling of the string.

Abstract: An air shooting system for use in lieu of explosives in the mining of coal employing a set of tubular shooting heads fitted in respective shot holes in a coal seam. Each shooting head is fed with air under high pressure and has a valve mechanism for triggering discharge of the air when it reaches a predetermined pressure. The source of air pressure is connected to a manifold and automatic shut-off valves are interposed between the manifold and the lines feeding the individual shooting heads. Each shut-off valve has a movable valve element biased into a normally open position to permit flow of air from inlet to outlet but which is snapped into closed position and held there by the inlet pressure when there is a sudden drop in pressure at the outlet accompanying discharge at the associated shooting head. The shooting heads are set to trigger in series at incrementally spaced pressures until all of the shut-off valves are in closed condition.