Walking down the path towards Portella Colla, you reach Piano Trifoglio (1460 m a.s.l.); this is a wide flat surface representing a back-tilting area due to large landslide movements developing from the western slope of Monte Mufara. On the surface there are several aligned small dome-like reliefs. These are manmade formations, consisting of debris mounds created by former mining activity in the nearby quarries; the self-sown vegetation has turned them into small and singular grass hills.