Abstract: A dam structure for retaining water in a reservoir includes precast concrete panel assembly forming the face or upstream side. A bonded impervious liner means, such as polyvinylchloride sheet, is provided on the downstream face of the precast concrete panels assembly. The liner means includes individual membranes bonded to adjacent panels, and heat welded impervious strips are provided along the joints between the panels. A poured concrete curtain wall is provided adjacent the liner means of the precast concrete panel assembly. Roller compacted concrete (RCC) is then provided in layers on the downstream side of the poured concrete curtain wall. An elongated, substantially horizontal blocking sheet of polyvinylchloride membrane is also provided at least adjacent the base of the dam to prevent water migrating upward through the dam between the precast concrete panels and the poured concrete curtain wall.

Abstract: An improvement in a mixture concentrator on the one hand, or a fluid medium separator on the other, that is usable, for example, for significantly increasing the amount of proppant in a formation fracturing foam is disclosed. The concentrator is comprised of an elongate vessel, a rotor rotatably mounted inside the vessel on a shaft and a motor for rotating the shaft. The vessel has a mixture intake at a forward end and a concentrated mixture outlet and a fluid medium outlet at the rearward end. Mounted on the shaft near the mixture intake is a cylindrical stabilizer which imparts a spin to the incoming mixture. Also mounted on the shaft, downstream of the stabilizer and of the mixture intake is a intake impeller means for removing substantially only the fluid medium from the mixture which is located in the annular channel between the vessel and the rotor to an internal passageway located inside the rotor.

Abstract: A concentrator or mixture separator usable, for example, for significantly increasing the amount of proppant in a formation-fracturing foam is disclosed. In a particular embodiment the concentrator or separator is comprised of a substantially horizontally extending vessel, a rotor rotatably mounted inside the vessel on a shaft and a motor for rotating the shaft. The vessel has a slurry intake at a forward end and a concentrated slurry discharge and proppant carrier discharge at the rearward end. Mounted on the shaft near the slurry intake is a cylindrical stabilizer which is for imparting a spin to the incoming slurry. Also mounted on the shaft, downstream of the stabilizer is an intake impeller assembly which can be comprised of a plurality of annular intake impellers, a discharge assembly which can be comprised of a plurality of annular discharge impellers, and a connecting housing therebetween.

Abstract: The amount of proppant in a formation fracturing foam is significantly increased by the disclosed method and apparatus.