Abstract: A dragline has two booms at a ninety degree angle with the dragrope between them. Each boom has a variable speed hoist mechanism and both hoist ropes are connected to the bucket. Either boom can be used as a digging boom, with the other serving as a dumping boom, and relative hoist speeds are controlled to move a filled bucket to a dumping position under the dumping boom and back to start position under the digging boom.

Abstract: The guide bushing of a blast hole drill is resiliently mounted to dampen lateral vibrations of the drill string. The mounting arrangement comprises four pads symmetrically placed about the bushing and restrained against all but radial movement. Each pad includes a radially inner bearing section that bears against the exterior of the bushing, an outer backing section that is radially movable with respect to the bearing section, and a resilient cushion between the two sections. A four-lobed cam ring surrounds and faces the backing sections and is rotated to simultaneously load all the cushions to a selected degree. In the preferred embodiment, the mounting components are in an enclosed housing that defines guide channels for the pad and that can easily be fitted into the deck of a machine.