Abstract: A power mining shovel including a drive train drivingly connected to ground-engaging device, the drive train including a drive train shaft, and a disc brake apparatus operably connected to the drive train shaft for selectively preventing rotation of the drive train shaft, the disc brake apparatus including a brake hub mounted on the drive train shaft for rotation therewith, the brake hub including an outer member rotatable about the axis, the outer member including an inner wall defining a generally cylindrical bore centered on the axis, the inner wall having therein a plurality of recesses, the brake hub also including an inner member rotatable about the axis, the inner member including internal splines engaging the drive train shaft to prevent relative rotation of the inner member and the drive train shaft, the inner member being located in the bore of the outer member and having a generally cylindrical outer wall, the outer wall having therein a like plurality of recesses, each of the recesses in the outer