LE BOSC (LODEVE, SAINT-MARTIN-DU-BOSC)

Type: mines and plant for ore processing

Location: a 4 km2-area at Bosc (Hérault). The installations are located at the place called Saint-Martin-du-Bosc, south of the city of Lodève

Operator: Cogéma, Simo

Period of operation: 1975-1977

Raw materials: uranium ore

Nominal capacity: factory, 900-1000 t/yr of uranium

Actual production: factory, in 1995, 500 t/yr

A surface mine, Le Mas d’Alary, was operated by Cogéma. Operation, which began in 1978 and ate “the mountain and [a] village” has ended [LeMo 6.vii.80]. During 1985 alone, the mine produced 1,000,000 t of ore [InfoU I-ii.86].

An underground mine, Le Mas Lavayre, was operated by Cogéma from 1975 to 1997. During 1985 alone, 340,000 t of ore were produced [Bugarel 86]. The mine was extended after 1995 by the underground mine Capitoul (extension to the west of the river Lergue) [Bugarel 96]. Production in 1995 was 485 t of uranium [CogRa 95].

Simo began to operate the plant in 1981. It shut down in 1977. It treated ore from mines in the Lodévois concession, towards the end of operations only those of Mas Lavayre and Capitoul [Bugarel 96].

Capacity amounted to 900 or 1000 t/yr of uranium. The plant treated in all 4,379,000 t of ore, containing 13,584 t of uranium [Andra 96]. Because of the carbonates in the ore, Le Bosc was the only plant in France having recourse to an alkaline attack. The product was in the form of magnesium uranate, 70% uranium.

The plant released acid effluents and radioactive effluents. According to CEPN, only the radioactive effluents were significant. Measurements of external exposure and of alpha energy from radon 222 were higher near the plant than background radioactivity measured quite far from the plant [Dreicer 95].

On the site are stored 4,564,000 t of tailings, containing 14,238 t of uranium, the majority in two surface mines. The mines also contain sludges from the treatment of water. In addition, the site stores 823,000 t of poor ore at 0.74%, containing 607 t of uranium. The activity of the radium 226 and of the thorium 230 in the tailings comes to 350 TBq [Andra 99; Dreicer 95].

The liquid effluents coming from the treatment plant for minerals that were not contaminated by radium are released directly into the Lergue. The effluents from the water treatment plant were released into the Rivernoux via le Riviéral and the Bourgnous. The CEPN detected soluble uranium 238 and soluble radium 226 in the Rivernoux [Dreicer 95].

“Mine flooding work” was carried out in 1997 to reduce radon emissions and external radiation “from the tailings” [NucF 26.i.98]. As of February 1999, the tailings were being covered. The poor ore was being used as the first layer of the cover over the tailings [Andra 99]. Dismantling of the mill was to start at the beginning of 1999 and last about a year [CogRa 9].