Abstract: A floating apparatus for providing pressurized air to a submerged swimmer. A floatation device supports a combination of two containers above the surface of the water. The top container, in the form of an inverted box, holds one or more electrically powered compressors. The bottom container holds a battery for powering the compressors. Water ingestion by the compressor(s) is prevented by placing the air intake inside the upper box, which forms an air trap. The air intake and compressors are isolated from any possible contamination or explosion risk from the battery outgassing, which is safely vented to the outside air from the lower compartment. Battery life is extended by pressure switch controls on the air compressor(s), running them on demand instead of continuously.

Abstract: The obdurate hard cake, loaded with gold particles, that forms on the bottom and four sloping walls of the reciprocating deep rectangular jig pan by the compaction and dewatering of the suspended solids is eliminated, and the recovery of gold is significantly improved by a combination of:1. a rectangular pressurized water manifold spaced slightly above the plane of the pan bottom and provided with at least one row of jet orifices directed at the bottom;2. four steeply sloped walls at a dihedral angle of about 65.degree. with the plane of the open top of the pan;3. a V-bottom with the valley aligned parallel to the flow of slurry;4. a broad skimmer blade on the spillway gate, oriented coplanar with the surface of the slurry and directed backwardly against the flow;5. a connecting rod in the drive train which is resiliently biased, in thrust and in pull directions, by adjustable spring means;6.