The United States of America As Represented by the Secretary of

The United States of America As Represented by the Department of Health

Sterling J Anderson

Wallace W Roepke

An apparatus (10) for placing a hard compact material such as rock surrounding a drill hole into axial tension for the purpose of breaking and excavating the material by virtue of a dual piston (23) and (25) arrangement disposed within a fluid cylinder (16) wherein the first piston (23) is attached to a thrust rod member (28) the second piston is attached to a wedge member (30) having an outwardly tapered conical end (34) and a feather member (40) surrounding the wedge (30) and thrust (28) members; wherein the feather segments (43) have a conical profile on both their internal and external peripheries.

Hydraulically actuated mechanical rock excavator

A longwall mining machine comprises a rotatable cutting head having a configuration in the form of an equilateral triangle viewed along its axis of rotation and formed with a continuous auger along the outer surface of the head. Cutter bits are located on apexes of the auger. The cutting head is mounted on a boom adjacent the longwall and is geared to produce an eccentric Cardan motion to the head causing the cutter bits to follow a substantially square trajectory in a plane normal to the axis of rotation of the head. Production of coal dust is minimized by deep linear vertical and horizontal cuts extending downwardly from roof to floor. During rotation of the head, cut coal is augered outwardly from the longwall and dropped into a conveyor for removal to a collection area.

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Maple Grove, MN, United States of America

Sterling J Anderson