8. River Tinto
Our own little Mars on Earth is in Spain. The similarity of this strange place with the red planet so high that NASA because of it conducted various experiments here. This river creates such an unusual environment of the tremendous acidity, namely red color it betrays a high copper content. All this is due to the fact that the extraction was carried out on the river gold and copper.
The Río Tinto is a river in southwestern Spain that originates in the Sierra Morena mountains of Andalusia. It flows generally south-southwest, reaching the Gulf of Cádiz at Huelva.
Since ancient times, a site along the river has been mined for copper, silver, gold, and other minerals. In approximately 3000 BC, Iberians and Tartessians began mining the site, followed by the Phoenicians, Greeks, Romans, Visigoths, and Moors. After a period of abandonment, the mines were rediscovered in 1556 and the Spanish government began operating them once again in 1724. As a possible result of the mining, the Río Tinto is notable for being very acidic (pH 2) and its deep reddish hue is due to iron dissolved in the water. Acid mine drainage from the mines leads to severe environmental problems due to the heavy metal concentrations in the river. In 1873, the Rio Tinto Company was formed to operate the mines; by the end of the 20th century it had become one of the world’s largest multinational mining companies, although it no longer controls the Río Tinto mines; these are now owned by EMED Mining.