The Riotinto-Nerva mining basin is a Spanish mining area located in the northeast of the province of Huelva (Andalusia), which has its main population centers in the municipalities of El Campillo, Minas de Riotinto and Nerva, in the region of the Cuenca Minera. It is also part of the Iberian Pyrite Belt.
Historically, this area has been exploited for mining purposes, and a major industrial complex was established in contemporary times. Although there is evidence of this type of activity in the area during protohistoric times, it was not until Roman times when an organized exploitation of its deposits took place. After the activity of the mines was resumed in the Modern Age, the Riotinto basin experienced its peak between the end of the 19th century and the middle of the 20th century under the management of the British Rio Tinto Company Limited. A significant industrial and demographic boom took place during those years. Nowadays, the mineral extraction activity continues, mainly in the Cerro Colorado, although without reaching the production levels it had in the past.
The basin holds an extensive historical and industrial heritage as a result of the activities that took place during the Contemporary Age, especially those related to the British period. As a result, in recent decades various initiatives aimed at its preservation and use for tourism purposes were implemented. In 2005, the Riotinto-Nerva mining area was declared Bien de Interés Cultural with the category of Sitio histórico.[1]
Characteristics
The Riotinto-Nerva mining basin is located in the northeastern part of the province of Huelva, within the historical region of eastern Andévalo, at 418 meters above sea level. The basin has an approximate extension of 170 square kilometers. Like other deposits in southwestern Spain, the Riotinto-Nerva area is part of the Iberian pyrite belt.[2] Because of this, it has important reserves of pyrite and chalcopyrite, minerals with multiple applications in the field of industry. The mining area is framed within the low mountain landscape that predominates in the Andévalo, with a relief of relatively smooth terrain - between 700 and 500 meters. In terms of physical geography, there are hills, mountains, and eroded areas. Notably, the physiognomy of this area has been considerably altered throughout history as a result of mining activity.[3]
The Riotinto complex was formed by several polymetallic masses extending over an area of 4 square kilometers and hosting a total of 500 Mt (megatonnes) of ore.[4] The main formations identified are Filón Norte, Filón Sur, Masa Planes, Masa San Dionisio, and Masa San Antonio. The latter extends over the municipality of Nerva and, compared to others, is the most recent mineral formation (second half of the 20th century). The presence of the
History
From Antiquity to the Middle Ages
The Riotinto mines have been described as "one of the most important mining districts" of Antiquity.[6] There is evidence of the existence of mining activities in the area of the current basin during the Copper Age and the Bronze Age, although these would not reach a greater relevance until several centuries later. The isotopic analysis at Riotinto have revealed that there was already considerable activity since at least 366 BC,[7] while the oldest remains of mining operations and human settlements have been found in the area of Filón Norte.[8] The minerals may have had two possible export routes: a first route, that reached the Guadalquivir River through a complex mountain road; and a second, through the Tinto River.[9]
Industrial heritage
Several industrial facilities linked to the mining activity have been built since the reactivation of the mining basin in the 18th century. One of the oldest that have survived to the present day is the San Luis Smelter, built in 1832 next to the South Seam to house the metallurgical activities. The Rio Tinto Company Limited later built new facilities in the area, such as Fundición Mina (1879), Fundición Huerta Romana (1889) or Fundición Bessemer (1901), as well as Cementación Cerda and Cementación Planes to carry out the copper extraction works by wet process.[43] Later on, all hydrometallurgical processes would be concentrated in the Zarandas-Naya area with the construction of Cementación Naya and, in 1932, of the ferrous sulfate ponds. There was also an acid factory installed in Riotinto, which started operating in 1889, followed by a second sulfuric acid plant built in 1929.[55]
With the expansion of activities throughout the basin, the RTC provided electricity as a source of energy to its industrial facilities, the homes of the British personnel, workers' villages, etc. In 1907, a power plant was built in the Huerta Romana area, which was operational between 1909 and 1963.[56]
Starting in the 1880s, ore processing plants were installed in the Zarandas-Naya area, initiating a process of industrialization that would reach its peak in the early 20th century.
Railway network
Between 1873 and 1875, the engineers of the RTC built the Riotinto railway to connect the mines with Huelva,[64] in which port was also built a pier. An extensive network of tracks and branches was formed within the basin over the years, connecting the general track with the industrial installations and with the deposits, as was the case of Filón Norte, Corta Atalaya, etc. Among others, branches were built that connected with the Peña del Hierro mine (1883), the branches that reached Zalamea la Real and Nerva (1904) or the subway connection of the Naya tunnel (1916). Two railway complexes were also created, Río Tinto-Estación and Zarandas-Naya, which had wide tracks for receiving and classifying the mining trains.[65] The Riotinto railway was for a long time one of the most important railway lines in Spain, both for its kilometers of track and its extensive rolling stock.[66]
Also operating in the basin was the Peña del Hierro railway, which was active between 1914 and 1954.[67]
See also
- Mining Basins (Asturias)
- Río Tinto Foundation
- Riotinto Railway
- Rio Tinto Company Limited
- Tharsis-La Zarza mining basin
- Tourist Mining Train
- Peña del Hierro mine