A multi-shank ripper excavation tool has a body mounted from an arm, e.g. a dipper arm or a boom arm, and at least first and second shanks mounted to the body. Each shank is perpendicular to an axis of rotation of the tool, and each the shank includes a ripper tooth positioned for ripping engagement with a substrate. The shanks and ripper teeth are laterally spaced apart along the axis of rotation relative to the arm, and the ripper teeth are angularly spaced apart in a direction of substrate ripping motion. In some implementations, plates are mounted to span a region between two or more shanks, rearward of the teeth in a direction of ripping motion, and define, with the shanks, a bucket volume for receiving material ripped from the substrate. Methods for ripping excavation of a substrate employing the above excavation tools mounted on a dipper stick or a boom arm are also described.