PURPOSE: To prevent water polution with an improved cycle time by means of a water injection pressure air mixing pump mounted in a bucket of a hydraulic power shovel.

CONSTITUTION: A hydraulic shovel 1 is operated to enfold a bucket 2. A high presure water injection pump 5 and an air compressor 6 are driven and excavate and dredge actuating a water injection pressure air mixing pump 3 in the bucket 2. When a high pressure water 7 from a shooting nozzle 8 is shor toward a suction tube 12 simultaneously with a pressure air 9 from a shooting tube port 11 via an inlet 10, earth and other matters excavated in the bucket are sucked by a strong force being generated and sent to a accumulator 15 installed ashore through a fluidic feed tube 13.