Valle Antrona (Antrona Valley) is a valley of the Alps, situated in the Pennine range. The valley is drained by the Ovesca, a tributary meeting the Toce at Villadossola, one of the seven valleys of the Val d'Ossola. It has a total of 1,140 inhabitants, distributed over an area of 141.43 km². Sporting the Alta Valle Antrona Natural Park, it is situated to the north of the Valle Anzasca. Historically it was the site of gold and mica mining. Its demonym is "Antronesi".
Etymology The valley takes its name from the town of Antronapiana.
History The Antrona valley and all of the Piedmont region formed part of the Kingdom of Sardinia prior to the creation of the Kingdom of Italy in 1861.
According to local legend, the town of Antronapiana was the subject to a large landslide at the beginning of the 18th century, creating a barrier dam and flooding the town.
In the early 19th century the only access to the valley was via a dangerous mountain road, described in 1819 as: It crosses the side of a high mountain which has completely collapsed: above all one can see nothing but loose earth and large stones with fragments and debris in bulk, where the landslide, although not continuous, has already caused the death of several passengers. Below then there is a deep abyss where the stranger, unaccustomed to such dangers, trembles and trembles at every step; considering which cannot place its foot except on a very narrow false bottom, mobile and slippery at the slightest impact.Valley life in the 19th century was difficult with much of the population engaged in transhumance. The economy of the valley centred around cattle, charcoal, and mining. The latter developed rapidly in response to a 1786 essay on mining by Spirito Nicolis di Robilant. Iron mining also occurred at Montescheno and a trip hammer appears on the coat of arms of Borgomezzavalle. Ironworks were located at Viganella and Villadossola in 1819.
Mining History
The Antrona Valley is situated at the northern end of the Monte Rosa Gold District and organised hardrock gold mining occurred over a period of some 200 years between the mid 18th and mid 20th centuries.
Gold mining in the valley is concentrated in the vicinity of frazioni of Locasca and Prabernado on the slopes of Punta di Tivera in the comune of Antrona Schieranco. In 1776 Victor Amadeus III granted Carlo Andrea Morandini prospecting rights at Trivera Alp; family was still working it in 1866. The Antrona gold mines are mentioned by in 1786 by Spirito Nicolis di Robilant, when he was General Inspector of the Piedmontese Mines and whilst Piedmont still formed part of the kingdom of Sardinia. The mines mentioned at this time were Porticciô de St. Pierre, Camasca, Antrona and Filon de Saut. The latter was the richest with ore grades of 6 dram, 6 grain to the hundredweight. In 1817 there were a total of 10 underground workings in 8 separate locations. +Of the gold cave cultivated in the Antrona valley in the year 1817Owner (surname)LocationNumber of WorkingsMorandini Mr Antonio MariaIn Trivera at Mottone.2Pozzoli Mr. Gio. Angiolo, parish priest, Moggia brothers Giuseppe and Ambrogio Luigi, Plosa Gio, Jacaccio Pietro, Rossi Francesco, et al.Idem.1Mr. Carl'Antonio Laurini, Antonio Maria Morandini, and other members of the Chiolino Alberto family.In the Mee Fountains2Guaglio Francesco, purchaser of Frisa Gio.At Bricco delle Mee or in the Fountains1Mutti Alberto and Plosa Giovanni and other members.At Croppi or at Cantonaccio1Bellardo AntonioAt Balmaccio above Locasca1Guggia Pietro and Moggia FrancescoIn Camma 1Mutti Alberti and CompanionsIn Trivera at Mottone on the Piano Scaglie1Total10 Mining continued at principally in two separate mines that were often worked together, known as Mottone-Mee and Prabernardo-Locasca. The Vallone Trivera where they are situated is known locally as the "Valley of the Gold Mines". The Mottone-Mee mine was still being worked by the Morandini family in 1866 when royal licence was again granted by letters patent. The Prabernardo-Locasca mine was worked from 1870-79 by the Anglo Italian Mining Company Limited, and then until 1899 by a private company. Mottone-Mee and Prabernardo-Locasca mines were amalgamated by the Swiss Sociètè des Mines d'or d'Antrona in 1898 and worked together until 1902. The company built a large workshop in Locasca, consisting of a crusher, a battery of 10 Kupp pylons, and a cyanidation plant, which precipitated the gold on lead plates using electricity. This plant was later replaced by a precipitation plant using zinc shavings. The concession was afterwards transferred to the Antrona Gold Mining Co. Ltd in 1902 and was still operating in 1936 after having been transferred through a series of joint stock companines.
The Prabernardo-Locasca mine () worked two lodes known as the Cava del Bosco and Toni. These were accessed by two crosscut tunnels: the Taglione (880m a.s.l.) and Toni (950m a.s.l.), both are about 350m in length. The development of the mine on the ore bodies continues for about 100m northwest-southeast. Other prospecting drives were opened at La Chietta (960m), Prete (905m), and Frisa (1018m and 1060m).
The Mottone-Mee mine () was described as "undoubtably the most important" in the Valley. Alpe Mulini (Mills Alp) acquired its name from the modified Alpine grain mills used to process the gold ore by the Morandini family of Alpe Trivera. The ore contained finely disseminated gold particles in a quartz-sulphide matrix.
From the village of Locasca, a mule track with 52 hairpin bends leads to the Mulini, the Mottone-Mee mine was then developed principally from the Fajot tunnel (1460m a.s.l.) and an aerial ropeway took ore back to the processing plant at Locasca. The lodes outcrop at Alpe Mee (1850m) and Alpe Mottone (1900m). A second aerial ropeway connected the Mottone-Mee workings with Mulini.
Geology The ore bodies are hosted both in the mica schists, fine and Ghiandoni gneisses. The gneiss-related deposits generally appear as discordant veins in a lithoclase field approximately orthogonal to the schistosity while in the mica schists the most common bedding is concordant.
The lodes of the Mottone group are almost vertical and oriented generally NNW-SSE; their thickness varies from a couple of meters to 40-50 cm or less. The ore body is approximately 150 m in length with a depth of over 200 m. Mineralization is concentrated in preferential zones, forming richer "columns". Gold (in grades of around 5-10 gram/ton in the sorted bulk) is bound to sulphide and iron sulfoarsenide, occasionally accompanied by galena; the gangue is composed primarily of quartz, in which are found embedded fragments of the surrounding gneiss, silicified and sericitized.https://www.researchgate.net/publication/303854348_Alpi_Occidentali
Geography The Antrona Valley is surrounded by mountains on its north, south and west sides. The minimum altitude of valley bottom is 450 m above sea level. Road access is via its opening in the east in Montescheno comune, following the route of the Ovesca River. The Pizzo d'Andolla at 3,656m is the highest mountain in the valley, forming part of the Swiss-Italian border. The valley encompasses the comunes of Antrona Schieranco and Saas-Almagell in the west and Borgomezzavalle and Villadossola in the east.
The Alta Valle Antrona Natural Park is located within the valley.
Mountains
The valley is situated in the Pennine Alps, more specifically, in the Andolla range.
The main mountains surrounding the valley are:
Pizzo d'Andolla - 3,656 m Pizzo Bottarello or Sonnighorn - 3,487 m Pizzo Loranco or Mittelruk - 3,362 m Pizzo Scarone - 3,341 m Jazzihorn or Pizzo Cingino Nord - 3,226 m Punta di Saas or Latelhorn - 3,200 m Punta Laugera - 2,995 m Punta della Rossa - 2,911 m Punta Turiggia - 2,811 m Pizzo San Martino - 2,733 m Pizzo Montalto - 2,705 m Pizzo del Ton - 2,675 m Pizzo Ciapè - 2,394 m
Passes
Antrona Pass or Saas Pass (2,839 m) - towards the Swiss Saastal valley. Cingino Pass or Jazziluke (3,080 m) - towards the Swiss Ofental Valley. Antigine Pass or Ofental Pass (2,833 m) - towards the Swiss Ofental Valley.
Hydrography
Water in the Antrona Valley is a significant resource; streams and lakes abound. The Ovesca river, from its headwaters at Lake Antrona, runs the entire course of the valley. Lake Antrona was formed naturally following a landslide in 1642; its main tributary is the Troncone from the Pizzo d'Antigine. Shortly before flowing into Lake Antrona, the waters of the Troncone are dammed, creating the artificial Lake Campliccioli and used for hydroelectric power. Another artificial lake is Lake Cingino, located at 2,262 m above sea level. It is famous for its Alpine Ibex, who ascend the nearly vertical wall of the dam to lick salts (saltpeter).
In addition to the Troncone, Lake Campliccioli is also fed by the outlet of Lake Camposecco, also used for hydroelectric power. After passing the Campliccioli Dam, the Troncone quickly descends to Lake Antrona and ultimately to its outlet at the Ovesca River.
The Ovesca then reaches Antronapiana and receives one of its largest tributaries from the north: the Loranco. The stream rises at the foot of Pizzo d'Andolla and near Alpe Cheggio is dammed to form Lake Alpe dei Cavalli (or Lake Cheggio); the largest body of water in the Antrona Valley and also used for hydroelectric power. After passing the dam, the Loranco flows through the pastures of Alpe Cheggio and Alpe di Campo, finally reaching Antronapiana. After receiving the Loranco, the Ovesca continues down the valley, receiving various tributaloreries from both sides. Downstream from Montescheno, it receives its largest tributary: the Brevettola River, which rises on the slopes of Pizzo San Martino and then flows past the hamlets of Montescheno.
The Ovesca River then leaves the Antrona Valley and descends into the Ossola Valley, where it flows into the Toce River after passing through Villadossola.
Climate The Antrona Valley has a typically Alpine climate with long, harsh, snowy winters and cool, rainy summers. Precipitation is frequent and the valley sports one of the highest average annual rainfall in Italy. Rainfall is more frequent in autumn, especially in October, often causing serious problems such as flooding and landslides. Snow covers the valley's main peaks for long periods and in the coldest months it also falls to the valley floor. The highest peaks also feature some small glaciers. In winter the valley bottoms are often covered by a thick layer of ice that only melts in late spring.
Monuments and Places of Interest The entrance to the Antrona Valley is located in Villadossola but the valley itself begins in the Montescheno comune. This municipality is a cluster of hamlets nestled among orchards, pastures, and chestnut groves. The first town you come across is Cresti, the seat of the municipality, which also houses the Parish Church of Saints John the Baptist and Charles. From Cresti, a secondary road leads to Sasso, Barbuniga, Vallemiola, Valleggia, and Zonca. Vallemiola enjoys a sunny position and houses the Oratory of the Madonna delle Grazie and two large ancient wine presses. One of the presses has recently been restored. In Valleggia, there is an ancient wine press and a typical hamlet's bread oven. Barbuniga also has a press, still in excellent condition, built in 1745 and no longer in use since 1980. Barbuniga also features a traditional bread oven, and before World War II, there was also a large hamlet still for the production of grappa, of which no trace remains today. The hamlet of Zonca can only be reached on foot, and it houses two presses and two hamlet ovens.