In Penamil there is one of the largest mines of Navia de Suarna. It is an open-cast mine that extracted the alluvial deposit on the left bank of the Navia River. There are two main areas, with several cuts following a SE-NW direction on two levels. The lower level is smaller and just about reaches the river itself. There, only some surface washing of ore occurred. Above this level, the upper area is much larger, and it includes many fronts of contour strip mining. Despite more recent alterations, the fronts can still be clearly seen –some are of great size–, as well as the accumulations of boulders. In the southern end of the mine, an outcrop bears witness to the original ground level before extraction began. On it there lies the archaeological site of Las Achicharres, whose location and morphology indicates a direct relation with the mining activity itself.