Abstract: Concrete is transmitted from a hopper forming a part of a mobile concrete pumping apparatus to the deposit site through a flow line having a Y-pipe inlet. The pumping apparatus includes two piston-cylinder concrete pumps mounted in side-by-side relationship adjacent the hopper, which has an auger to rapidly charge a pump with concrete through one of two discharge pipes. Each pump is pivotally mounted, to locate the cylinder aligned with the discharge pipe or with one inlet of the Y-pipe inlet. Each pump has a valve plate pivoting with the cylinder to alternately close the hopper opening and the inlet line. Hydraulic cylinder units are coupled to the valve plates to pivot the pumps. A floating valve plate has coupling pipes attached to the hopper and a hydraulic cylinder urges the same into sliding sealing engagement with the rotating valve plate.