In the GBM designed semi-portal scrapers, the portal spans a stockpile that has a lateral or peripheral retaining wall.
One rail track is located at the foot of the stockpile and the opposite track supporting the portal end is located in a raised position on the retaining wall of the stockpile.
Semi-portal scrapers are also applied in circular stockyards. In this design, the portal is supported on one side by a ball-bearing slewing ring at the center column and on the other side by an undercarriage on a ring rail.
