Method for reclaiming opencast sites in the central and southern coalfields (HBCM, groupe Charbonnages de France)
Résumé
The activities presented are the result of collaboration between HBCM, INERIS, responsible for the coordination of the studies of the sites within the context of an ECSC research project, "Rehabilitation of old mine workings", and SIR AS, a branch of CNR, responsible for managing the restoration project in the mining sites belonging to the Herault Operations Unit. The mining deposit of Graissessac basin extends over 20km and is in the form of a syncline, 2km wide in the area being mined. The underground workings were shut down in 1962 after a total coal production of 30 million tonnes. The mining was developed mainly along the north flank of the syncline, in 7 to 8 seams of between 30° and 50° dip. Since 1956, 4.6 million tonnes of coal with 29 million m3 of overburden were extracted by open-pit on 5 mountain massives (Plaisance, Rive Gauche, Rive Droite, Cap Negre, and Orb). The mining ended in 1993. The pits situated at mountains tops, were worked in benches, frequently leaving as such, with no backfilling, while the overburden materials were dumped on hillsides, at limit of equilibrium at heights of 40 to 250 metres. Altogether, the sites to be reclaimed represent an extend of 400 hectares. The provisional duration of the work is 4 years. CdF has decided to carry out a particularly exemplary restoration on the Herault sites and has procured the necessary financial and technical means.
Domaines
Sciences de l'environnement
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