of the area of Biella—the torrent Orco, for example—are noted for the presence of gold-bearing sands. In the case of the Orco these are concentrated in...

in Valprato Soana, where a number of smaller torrents converge. It is the principal tributary of the Orco, which it joins at Pont Canavese. AA.VV. (2004)...

Bessa area are known, as are other Piedmontese watercourses such as the Orco, for the presence of bits of gold in the bed sands. Gold panning had in antiquity...