The excavations uncovered a building that housed a late 18th century forge used for the maintenance of the tools and structures of the adjacent magnetite mine, whose lower entrance was only 30 m away. The structure can be associated with a 20-year mining concession granted by King Vittorio Amedeo III to Giovanni Battista Rei di Boglio and partners in 1784. This was a dry-stone built rectangular building with an interior surface area of 3.7 x 1.8 m2. Several of the blocks used in the walls showed traces of mineralisation and drill holes, indicating their provenance from the mine. The drill holes constitute a chronological division, as the use of gunpowder in the mines in the area of Biella began in 1671. The excavations identified several dry-stone built structures: the forge workbench, a probable support for an anvil, and two stone paved floors at different levels. The excavation of the occupation surface remains to be completed; so far, levels relating to the end of activities and the abandonment of the structure have been identified. The finds consist of steel objects (spatula, mallet, chisel, nails, and pieces of metal sheeting...), iron and steel working waste products (minerals altered by heat, slag, and iron dust), fragments of ceramic vessels (_taches_ _noires_ and glazed ware of late 18th century date), as well as large quantities of wood charcoal ( a sack of this fuel was probably abandoned next to the forge). Among the stone materials removed from the room that came from the post-abandonment collapse of its perimeter walls there were four stone blocks from an oil mill with semicircular hollows of varying depths (in one case on contiguous sides of the block). Made from different types of stone (two of gneiss, one of syenite and one of mica schist), they appeared similar to those sometimes found on late medieval French sites. The present suggestion is that these were reused materials originally dating to a pre-18th century phase, which can be linked to a perpetual enfeoffment granted in 1570 by Duke Emanuele Filiberto to Gieronima Saura, wife of Pietro Liato, lord of Castelletto Cervo, and passed to Giovanni Oreggia in 1612. However, further research on the typology and technology of these blocks needs to be undertaken. Numerous terracotta blocks were also found, which probably once formed the lining of an archaic reduction kiln, similar to those seen on the wooded hillside below the mine. The kiln foundations were not identified, but they must be close to the excavation area. At the end of the excavation season, all the removed stone blocks, except for the stones from the olive mill, were used to consolidate and repair the perimeter walls of the forge. The stones from the olive mill were placed on a purpose-built platform next to it, while awaiting the site’s insertion into the existing visitors’ circuit of the archaeo-mining and archaeo-metalworking sites of the Val Sessera. A laser scanner was used to create a complete topographic survey of the mine. Based on this, work has begun on making a detailed description of the development of the mining activity and samples of charcoal and sediments were taken for laboratory analysis.

Gli interventi relativi alla campagna di scavo 2019 si sono concentrati in corrispondenza del settore in toponimo Pietrara. Pietrara Grazie all’ampliamento dei limiti del settore verso sud e alle ulteriori indagini stratigrafiche all’interno dei due ambienti individuati durante le scorse campagne è stato possibile confermare la presenza di un grande strato di matrice limo-argillosa di colore marrone chiaro ricco di frammenti ceramici collocabili tra la fine del I sec. a.C. e il V sec. d.C. e afferenti soprattutto alla sfera domestica e familiare. Tale evidenza, la cui formazione è collocabile dai materiali tra la fine del IV e gli inizi del V sec. d.C., risulta essere particolarmente interessante in quanto permette di collocare la fine d'uso della struttura proprio in età tardoantica. La presenza di materiali cronologicamente non antecedenti, almeno allo stato attuale delle indagini, al I sec. a.C. permetterebbe, seppure ancora in via ipotetica, di collocare tra la fine dell'età repubblicana/inizi età augustea la costruzione della struttura. Se le future indagini confermassero ciò, ci troveremmo dunque di fronte ad una struttura residenziale contemporanea all'attuale pavimentazione dell'arteria principale, la via Nomentum-Eretum, visibile per 140 m più a nord e, per una piccola parte, ad est delle strutture riportate in luce. Particolarmente interessanti sono state, infine, le indagini relative agli ambienti 1 e 2, già parzialmente individuati durante le due passate campagne e corrispondenti a due diverse fasi costruttive. Oltre ai dati forniti dai materiali rivenuti (tra cui, oltre ai resti ceramici, due frammenti di fistula plumbea, entrambi schiacciati e lunghi 0.55 m e 30 m circa, di cui uno con la scritta in rilievo FECIT) è stato infatti possibile appurare una differenza di quota tra i due ambienti: l’ambiente 1 (prima fase), infatti, doveva scendere ad una maggiore profondità rispetto alle strutture murarie dell’ambiente 2 (seconda fase), la cui costruzione ha avuto come conseguenza, evidentemente, un innalzamento di quota del piano di calpestio e un appoggio alle strutture della fase precedente.