Pierre Bérest, Bill Diamond, Antoine Duquesnoy, Gérard Durup, Bernard Feuga and Lothar Lhoff with the collaboration of Ignace Salpeteur

For the public, mining incidents and accidents are a tribute that is all the heavier insofar as the memory of the heyday of mining with its positive effects blurs. Increasing concern for safety and protection of the environment raises questions about the long-term consequences of what mining have left underground. The government has changed regulations so as to take into account these new demands. In this context, the question arises of the future of rock salt deposits, especially in Lorraine, where most active mines of this sort are located. Should techniques be used that leave the surface untouched with supposedly stabilized excavations underground? Or, on the contrary, should methods be used that make the surface cave in to fill the cavities? These questions have led the Mining Administration to call for forming a group of international experts to report on the current state of methods used to mine rock salt around the world and, in particular, in countries similar to France. This group should also draw the lessons for mines in France, notably Lorraine. This assessment’s major conclusions are reported.

Water resurfacing from abandoned underground mines: A predictive approach to changes in the iron content according to Paul Younger of the University of Newcastle

Jacques Laversannne and Katia Laversannne 

Younger’s major objective is to present a conceptual model that can be applied to variations in water quality in abandoned underground coal mines. The model is intended to lead to an empirical procedure for use by those who make decisions about managing abandoned mines. It thus contrasts with a more scientifically rigorous but impractical model. Since most methods, mainly North American, for predicting the production of pollution in open-pit mines resort to acid-base accounting, they do not hold for abandoned underground sites. It is necessary to be able to estimate the future quality of the water that resurfaces from abandoned mines, in particular its iron content, since this metal is the major cause of water pollution in coal-mining areas of the sort found in the United Kingdom. Moreover, there is adequate historical data on the iron content. On the basis of a reliable panel study of 81 cases in Great Britain, Younger has fulfilled his objectives 
without giving up scientific standards.
 

Claude Sauzay

As a mining history covering 130 years is drawing to a close in the Salsigne area (Aude Department, France), it has left traces in the landscape and environment. As usual at the time, unlike nowadays, neither the former mine operators nor public opinion in general were aware of the need to protect the environment. As the last operator (MOS) shuts down, the opportunity arises for restoring and rehabilitating certain abandoned sites in collaboration with other partners. Thanks to its efficient management of environmental parameters, MOS will thus help cope, as much as possible, with the aftermath of this mining history. The cost of restoring and rehabilitating all sites will reach nearly 55 million euros. This average of $15 per ounce of gold mined there is expensive when compared with the few dollars per ounce currently predicted when opening new gold mines. In Salsigne, public authorities are paying for a belated awareness of sustainable development. Nowadays, the costs of restoring a site once a mine shuts down are calculated in advance. 

From mining to developing underground resources

Pierre Duffaut 

Having failed to organize the mining of mineral deposits with a long-term view, which now exists reinforced by the requirements for sustainable development, society has to cope with the “postmining” problems of a scarred landscape: the quarries, slag heaps and landfills that might catch fire, sink or cave in; flooding; and damage to infrastructures and buildings. This is not a recent discovery, nor one specific to industry. Decade after decade, we have observed new damages that are hard to handle once mining companies have gone out of business. A series of examples serves to make the argument that it is worthwhile to “develop” underground resources — to favor a long-term management of the mineral deposits and excavations underground so as to improve the management of the postmining situation, once ore has been extracted. At the outset of mining operations, it would be wise to plan for using the cavities that will be made.
 

Jean-Charles Besson

Since 1946 thanks to the law on nationalizations, Charbonnages de France inherited 261 concessions from which 4,7 billion tons of coal were extracted. In April 2004, it put a halt to all activities for extracting minerals and has been devoted for several years (and now exclusively) to the social, economic and technical tasks of “postmining”. Under the Mining Code, postmining operations are advancing at a sustained pace with a permanent concern for information, accountability and concerted efforts. Teams in the company have been reinforced to handle one of the last phases in this firm’s life, as rehabilitation definitively replaces mining.