If that's a LeTourneau ripper, and the writing was done by one of their guys, they definitely knew how to weld. R.G. LeTourneau pretty much invented the concept of electrically welded fabrication of heavy equipment. Before him it was all steel plate, beams, and rivets.
Those things were bloody heavy, and a D7 with a cable winch (PCU) was the standard power unit. Britstand also made a single tyne "roto-ripper" , no PCU needed, as the tyne could be triggered via a rope to rotate from trailing to ripping position. A D6 was OK there. Regards,