The caving-ins at Ocnele Mari in the Vâlcea Subcarpathians, Romania

Abstract

Brine exploitation began in 1960 at Ocnele Mari for the purposes of chemical industry (chlorosodic products) at Oltchim and Govora industrial plants. Due to the increasing demand for salt and subsequently to its exploitation, huge underground cavities for the coalescence of extraction fields took place between the ’70s and the ’80s. Unlike other salt exploitations in the world, this is located within an inhabited area. Five extraction fields have been set up. In 2001 and 2002 a crater formed after three wells had collapsed in the extraction fields I and II, flooding and damaging twice 90 houses and over 200 people were evacuated; biodiversity of the Olt river fauna was endangered. At the moment the exploitation is planned to be continued for at least 30 years. Though, situation is difficult on a long term because other cavities could form and cause collapses, affecting 1500 people in Lunca, Ocnița, Gura Suhaşului and Coşota villages. According to the estimates made by authorities, the ecologic cleaning of the area itself will cost over 15 million €. Research work aims at identifying and mapping the collapsed areas, as well as surveying the evolution of geomorphic processes, based on the existing data and on the measurements made between 2004 and 2006.