On the left bank of the stream, the thickness of the brown coal bench is 4 meters, while on the opposite bank is 3.5 meters. At the foot of Trogna Mount, in Scopa Gamberi, the brown coal emerges with a thickness of 7 meters. The brown coal is xyloid, brown, shale and very humid as reported by studies made on brown coal deposits in the Continental Italy by the Geo-mineral Company on the Magazine of the mining services (GEMINA - 1962). This different thickness depends on the morphology of an ancient lake basin that occupied the valley between Leonessa and Ruscio during the Protohistoric era. On the bottom of this basin, in addition to sand and gravel clays, numerous plant remains are also deposited that, with the passage of time and with the pressure due to the materials placed on top of these, formed the brown coal.

The extracted material from this mine was transported to Terni via a cable car and later with trucks up to Ferentillo, where it was loaded on rail and transported to the Terni steelworks. However during the fervent activities of the ironworks in Ruscio, the brown coal was not yet discovered.