Objectif THE AIM OF THE R&D WORK IS THE SETTING UP OF A CHECKING SYSTEM OF THE UNDERGROUND CAVERNS EVOLUTION IN THE MINE EXPLOITED BY THE ORE SOLUTION TECHNIQUE. THIS SYSTEM WILL CONSIST IN A MICROSEISMIC MONITORING NETWORK AND VARIOUS SOFTWARES WRITTEN FOR MICROCOMPUTERS AND USABLE ON MINE SITE, ACHIEVING THE LOCALIZATION OF THE HYPOCENTERS OF THE SEISMIC PULSES, THE NUMERICAL MODELLING OF THE DISSOLUTION PROCESS AND, BY MEANS OF THE F.E.M. THE CALCULUS OF THE STRESSES AND DISPLACEMENTS INDUCED IN THE SURROUNDING MEDIA. A system has been developed to control the evolution of the cavities which are created during solution mining in order to ensure maximum safety of mining operations and to optimize the leaching procedure. Innovation methods have been developed for simulating leaching.Research was conducted in 2 phases, firstly, analysis of the problems leading to the definition of specific and general parameters, and secondly, sampling and analysis of data on the geostructural and geomechanical features and grades, leading to the definition of a geometrical grades model.The aim of this research project was to control the evolution of the cavities formed during the solution mining process of the brine field. The control was achieved by means of a modelization of the system, that is its geometry, of rocksalt grades and of geotechnical, seismic, rheological and leaching parameters. The simulation of the system allowed the design of the best method for the exploitation of the brine field and for the verifications of the production rate, of the safety conditions and of the environmental impact.The practical results of this study are fully exploited during mining operations for starting and control of single well leaching and for monitoring of subsidence. Leaching cavities have been designed with the aim of leaving a pillar and a slab in the rocksalt so that, having taken the rock's mechanical parameters into account, the stability of the cover of soil is assured. Temperatures, flows, pressures, pumps working times and stocks values collected during 3 shifts are recorded in a database. Approximately 600 data items are inserted daily into a personal computer and processed and periodical reports are printed. This procedure is a very efficient method for controlling quality and quantity of production, single well cavity impermeability and sodium chloride grade of the growing cavities.In addition to precision levelling to measure surface subsidence, inclinometric measurements to monitor slope stability, chemical analyses of surface and underground water to control pollution, the microseismic monitoring system is continuously working, and recorded data are processed every 3 months. The complex system under control (the orebody, the covering soils, the cavities by the leaching process, the brine still in the underground) is reaching, with the new exploitation method, a situation of dynamic equilibrium which seems to be stable due to the absence of a paroxysmal phenomena. The spatial analysis of the energy measured by the peripheral units o f the monitoring system clearly shows that microseismic signals can be related to exploitation activity.THE MAIN STAGES OF THE RESEARCH WORK WILL BE THE FOLLOWING : 1) SAMPLING AND PROCESSING OF THE GEOSTRUCTURAL, ORE GRADE AND GEOMECHANICAL DATA 2) DEFINITION, BY MEANS OF THE GEOSTATISTICAL METHODS OF THE GRADE SPATIAL STRUCTURE ACCORDING TO THE SAMPLED DATA. 3) NUMERICAL MODELLING OF THE DISSOLUTION PROCESS. 4) NUMERICAL MODELLING OF THE STRESSES AND DISPLACEMENTS FIELDS. 5) DESIGN, ASSEMBLING AND INSTALLATION OF THE MICROSEISMIC MONITORING NETWORK. 6) SOFTWARE IMPLEMENTATION TO LOCALIZE THE HYPOCENTERS OF THE SEISMIC PULSES. 7) COMPARISON OF THE OUTPUTS FROM DISSOLUTION, GEOMETRICAL AND SEISMIC MODELS WITH RECORDED DATA FROM MONITORING NETWORK. 8) FURTHER CONTROLS BY MEANS OF OTHER INVESTIGATIONS IT MAY BE EXPECTED FROM THIS RESEARCH WORK AN IMPROVEMENT OF THE KNOWLEDGE IN THE FIELD OF SOLUTION MINING, A BETTER CONTROL OF THE SHAPE OF THE UNDERGROUND CAVERNS CREATED BY THIS METHOD OF MINING, ENSURING CONSEQUENTLY BETTER SAFETY CONDITIONS AND AVOIDING DAMAGE TO THE MINE AND ITS ENVIRONMENT BY PREVENTING SUBSIDENCE OR SINK HOLE PHENOMENA. FROM AN ECONOMIC POINT OF VIEW, AN INCREASE OF PRODUCTIVITY AND THE OPTIMIZATION OF THE ORE RECOVERY WILL BE PROBABLY A CONSEQUENCE OF THIS WORK. Champ scientifique natural sciencescomputer and information sciencessoftwarenatural scienceschemical sciencesinorganic chemistryalkali metalssocial scienceseconomics and businesseconomicsproduction economicsproductivitynatural sciencesearth and related environmental sciencesgeologyseismologymicroseismsnatural sciencesearth and related environmental sciencesenvironmental sciencespollution Programme(s) FP1-RAWMAT 3C - Research programme (EEC) on materials (raw materials and advanced materials), 1986-1989 Thème(s) Data not available Appel à propositions Data not available Régime de financement CSC - Cost-sharing contracts Coordinateur Montedipe SpA Contribution de l’UE Aucune donnée Adresse Via Rosellini 15/17 20100 Milano Italie Voir sur la carte Coût total Aucune donnée Participants (3) Trier par ordre alphabétique Trier par contribution de l’UE Tout développer Tout réduire ASSOCIATION POUR LA RECHERCHE ET LE DEVELOPPEMENT DES METHODES ET PROCESSUS INDUSTRIELS France Contribution de l’UE Aucune donnée Adresse Boulevard Saint-Michel 60 75272 PARIS Voir sur la carte Coût total Aucune donnée Mining Italiana SpA Italie Contribution de l’UE Aucune donnée Adresse Via Chianesi 110 00128 Roma Voir sur la carte Coût total Aucune donnée Société Française d'Etude et de Réalisation d'Equipement Gaziers (SOFREGAZ) France Contribution de l’UE Aucune donnée Adresse 62 rue de Courcelles 75008 Paris Voir sur la carte Coût total Aucune donnée
