A mobile digging and backfill system for removing and collecting material above a buried utility. The system comprises a mobile chassis, a collection tank mounted to the chassis, a water pump mounted to the chassis for delivering a pressurized liquid flow against the material for loosening the material at a location, a vacuum pump connected to the collection tank so that an air stream created by the vacuum pump draws the material and the fluid from the location into the collection tank, and at least one backfill reservoir mounted to the chassis for carrying backfill for placement at the location.

An attachment is provided for us on an articulated boom of an excavator in order to excavate earth from beneath a buried pipeline or other utility. The attachment features at least one working arm pivotally mounted to a base plate for movement relative to the base plate about an axis passing therethrough. A working end of the arm is thereby movable between a retracted position overlying the base plate and a deployed position reaching laterally outward from an edge of the base plate. With the excavator facing in a longitudinal direction of the utility, and the attachment carried beside the utility at a short depth therebelow by the boom of the excavator, the arm can be deployed and retracted in order to sweep material out from under the pipeline and onto the base plate. The material is then lifted to the surface by raising of the excavator boom.

Vacuum units and vacuum trucks, for example, for excavating material, for instance, around buried utility lines. Multiple embodiments include an air and water nozzle that provides air and water to break up material (e.g., earth) that is picked up by a vacuum system. Various embodiments include a vacuum system, a compressed air system, a water system, and an air and water nozzle configured to be hand guided by an operator while excavating the material. In a number of embodiments, the air and water nozzle can include a body that is hand held by the operator while excavating the material, an air passageway through the body, a water passageway through the body, an air valve, a water valve, an air control that opens and closes the air valve, and a water control that opens and closes the water valve.

A pneumatic excavator includes: a barrel with an ingress configured to be fluidly connected to a supply of compressed air and an egress; an actuator; a releasable coupling to lock the actuator to the barrel in a plurality positions; and a flow valve fixedly arranged to the barrel, the flow valve in a communicative coupling with the actuator by an actuation conduit. The actuation conduit is flexible and slaved by an adjustment movement of the releasable coupling and actuator along the barrel to thereby maintain the communicative coupling therebetween. When the actuator is actuated, the actuation conduit sends causes the flow valve to open and the compressed air passes through the flow valve and exits the pneumatic excavator, and when the actuator is released, the actuation conduit sends a signal to the flow valve to close to prevent the compressed air from passing through the flow valve.

A device that excavates soil from beneath buried utility pipe. The excavated soil is pushed out using a piston shaft actuated ram's head. The piston shaft is attached to a power shovel's bucket. The piston shaft is hydraulically operated. Soil from the excavated area, when pushed out, falls into a previously dug opposite trench that is deeper than the bucket side trench where the shovel bucket is positioned for the pushing operation. Once the soil is pushed out from beneath buried pipe, the pipe is now accessible for inspections.