The Doñana Disaster, also known as the Aznalcollar Disaster or Guadiamar Disaster (Sp

Spanish language

Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...

: Desastre de Aznalcollar, Desastre del Guadiamar), was an industrial accident in Andalusia

Andalusia

Andalusia is the most populous and the second largest in area of the autonomous communities of Spain. The Andalusian autonomous community is officially recognised as a nationality of Spain. The territory is divided into eight provinces: Huelva, Seville, Cádiz, Córdoba, Málaga, Jaén, Granada and...

, southern Spain

Spain

Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

. On 25 April 1998, a holding dam burst at the Los Frailes mine, near Aznalcóllar

Aznalcóllar

Aznalcóllar is a city located in the province of Seville, southern Spain. It is located at the feet of the Sierra Morena.- Aznalcollar mine :The Boliden mine produces around 125,000 tonnes of zinc and 2.9 million ounces of silver per year....

, Seville Province, releasing 4–5 million cubic metres of mine tailings

Tailings

Tailings, also called mine dumps, slimes, tails, leach residue, or slickens, are the materials left over after the process of separating the valuable fraction from the uneconomic fraction of an ore...

. The acid

Acid

An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

ic tailings, which contained dangerous levels of several heavy metals, quickly reached the nearby River Agrio, and then its affluent the River Guadiamar

Guadiamar

The Guadiamar is a river of Andalusia, Spain, and a tributary of the Guadalquivir.It flows through Doñana National Park.In 1998, the company Boliden AB was responsible for a major ecological disaster in Spain, when a reservoir of toxic waste in the town of Aznalcóllar, owned by its subsidiary...

, travelling about 40 kilometres along these waterways before they could be stopped.