Walk along the path to the Obernberger See lake and then along the left shore of the lake to a bridge where there is a small chapel on the right. From there, follow the marked path to the Sandjoch until you reach a signpost at about 1700m. Then turn left over a flat area and a ridge. Continue to the right past a hill and into a hollow, which you follow to the Grubenjoch. On the Joch turn right over the ridge to the Grubenkopf.
Descent as ascent.