The Bessa gold mine

Sentences without a label are documented facts; the others are marked "probable" or "uncertain".

The Bessa plateau, halfway between Ivrea and Biella, is identified with the open-cast gold mines mentioned by Strabo and Pliny the Elder. Here the Romans washed a great deposit of pebbles and sand with water and the heaps of stones left by the work can still be seen in great numbers. This page tells where the gold came from, how it was extracted, who worked in the mine and when.

A deposit brought by the glacier

The morainic plateau of the Bessa is identified with the aurifodinae, the open-cast gold mines spoken of by Strabo and Pliny the Elder. The deposit was a placer, that is an alluvial deposit of pebbles and sand containing flakes of gold. The gold comes from the Aosta Valley, as the nature of the pebbles in the heaps shows: the Balteo glacier carried it here, then the glacial streams concentrated it in the gravels.

The terrace is a remnant of an ancient plain 8 km long and on average half a kilometre wide, up to 1.2 km near Vermogno. It stretches from Mongrando to Cerrione between the Olobbia and Elvo streams and descends from about 400 to 300 m above sea level; it stands 40 m above the Viona at Mongrando and 60 m above the plain of the Elvo at Cerrione.

Sources: Balbo 2018, p. 57; Sánchez-Palencia, Vaudagna 2008, p. 2; Gianotti 2011, pp. 183-185; Gianotti 2016, pp. 1, 4; Pipino 2010, p. 3

Washing the earth with water

The technique used the force of water: specially dug channels carried away the debris and made it possible to wash the gold-bearing sands, which contained little gold. The placer, however, lies 20-50 m above the beds of the Viona and the Olobbia: the water had to be taken further upstream and brought in by a channel, which according to Gianotti was about 2 km long. probable No supply channel has survived with certainty, because later digging gradually erased the water network of the earlier phases.

The survey carried out in 2008 by the CSIC, the Spanish National Research Council, indicates that water was used in every phase of the digging, with parallel furrows dug one after another: the large pebbles were piled in rows on top of the furrows already worked and this is why in the Bessa they always appear "orderly". probable The CSIC excavation thus called into question the older explanations, according to which the large pebbles were removed by hand. uncertain In the sand quarries on both sides of the terrace buried outlet channels have come to light, made of two rows of large pebbles laid without mortar and about 2 m wide. probable At the Barbera quarry at Cerrione, between 1975 and 1982, six single-pointed iron picks were found together with pottery thought to be Gallic, of the 2nd-1st century BC. probable

Sources: Balbo 2018, p. 57; Gianotti 2011, pp. 184-185; Gianotti 2016, p. 4; Sánchez-Palencia, Vaudagna 2008, pp. 6-7, 12; Pipino 2010, pp. 6-7, 12

The mine in numbers

• Area worked: heaps of pebbles over more than 4 km² on the upper terrace; Balbo gives 4.4 km² in all.
• Spoil: together with the spoil fans at the foot of the terrace they cover about 10 km², while the deposit proper measured about 5 km².
• Heaps: mostly long and parallel, they run down towards the Olobbia to the west and towards the Elvo to the east; they are separated by hollows called "bunde".
• Height: Calleri measured some more than 25 m high and up to 300 m long; Gianotti gives heaps generally 1 to 10 m thick. probable
• Fine waste: it forms the lower terrace towards the Elvo, in fans more than 15 m thick.

Sources: Pipino 2010, pp. 3, 5; Balbo 2018, p. 63; Gianotti 2011, pp. 183-185; Gianotti 2016, p. 5

Who worked there

After the expedition of Appius Claudius Pulcher against the Salassi, in 143 BC, the working of the gold passed to the publicani. Pliny mentions a censorial law on the gold mines of Victimulae, in the territory of Vercelli, which forbade them to employ more than 5,000 men; its wording shows that the publicani were organised in companies. It is rare for these companies to run a mine directly: this is why the case of Victimulae is a valuable piece of evidence. probable The purpose of the limit is debated and is discussed on the page "Those who think otherwise". uncertain The 4.4 km² of the plateau, in any case, were not enough for 5,000 people working at the same time: perhaps the contract also included other areas. probable

We do not know whether the workers were free or slaves, local people or natives who had surrendered to Rome. uncertain On top of many heaps there are hut floors, small hollows with remains of dry-stone walls and often Gallic pottery: these were their homes.

Sources: Pliny, Naturalis historia XXXIII, 78; Balbo 2018, pp. 58-59, 63; Sánchez-Palencia, Vaudagna 2008, pp. 4, 22; Pipino 2010, p. 5

When

Calleri's excavations at Mongrando and Vermogno yielded material of the end of the 2nd and of the 1st century BC, including a small hoard of silver coins. The 1995 excavation at Ciapej Parfondà yielded material of the end of the 2nd and the first half of the 1st century BC and no objects either earlier or from the Imperial period. The wooden handle of a pick, radiocarbon-dated, falls between the 2nd and the 1st century BC. probable The main phase of the mine lasted less than a hundred years.

Almost everyone dates the censorial law to the late Republic: Domergue places it around 70 BC, Balbo at the end of the 2nd century BC. In the Augustan age Strabo writes in the past tense that there was once a gold mine at Vercelli: by the beginning of the 1st century AD the mine was therefore already abandoned. probable For most scholars the colony of Eporedia, founded in 100 BC, was also created to protect Roman interests linked to the mine. probable

Sources: Sánchez-Palencia, Vaudagna 2008, p. 4; Pipino 2010, p. 13; Gianotti 2011, p. 183; Gianotti 2016, p. 4; Balbo 2018, pp. 58, 60, 65; Strabo, Geography V, 1, 12

The Bessa after the mine

After it was abandoned the Bessa was used for centuries by farmers and shepherds: there remain low walls, animal pens, small fields cleared of stones, tracks between the heaps and chestnut trees. The white quartz pebbles were almost all collected in the 1940s and 1950s for the foundries of Quincinetto and the Ivrea area. probable Since 1985 the area has been protected as a regional park: today it is the Riserva Naturale Speciale della Bessa and the enormous heaps can still be seen in great numbers. At the Barbera quarry a Roman outlet channel has been excavated and covered with a protective roof. probable

Sources: Pipino 2010, pp. 1-2, 4, 7, 12; Gianotti 2011, p. 183; Gianotti 2016, p. 1; Balbo 2018, p. 57

Open questions

The sources consulted do not give the point where the water was taken in or the route of the aqueduct. We do not know how much ground was being worked at the same time or who the workers were. uncertain For Balbo not even the date when the publicani gave up the contract can be fixed. uncertain Lastly, the final results of the CSIC campaigns of 2012-2013 are missing.

Sources: Sánchez-Palencia, Vaudagna 2008, pp. 4, 6, 12; Gianotti 2011, p. 185; Balbo 2018, p. 64