ABSTRACT:
In the paper it was realized the stress state simulation of the rock salt at solution mining operation. The paper presents also the Finite Element Method for modeling of the well and for the stress-strain state simulation it was used MATLAB Simulink software. This method takes into consideration the geomechanical characteristics of the salt obtained by laboratory tests for the purpose of dimensioning the geometrical elements of the resistance elements in order to prevent collapse up to the surface. The results of this simulation for Targu Ocna salt mine according to the measurements made by sonar devices during solution mining and surveying of the sinking land, helped us for drawn up a prognosis of land unsteadiness and of the impact risks over the environment.
1 INTRODUCTION
In Romania, salt is solution-mined at the Targu Ocna, Ocna Mures and Ocnele Mari mines. This mining operation is carried on by injecting water into the lower part of the salt deposit through boreholes; the brine flows up through each extraction well. Around each water injection well, a cavity develops upwards to the roof of the layer by the dissolution of salt. This study was carried out on a solution mining project at the Targu Ocna rock salt deposit, located in the Moldavia region. This paper seeks to analyse the stability of the caverns created in rock salt at the Targu Ocna mining area due to solution mining. In such a shallow deposit (the salt roof is about 200 meters under the surface) the final stability of each cavity, as well as the stability of the rock salt “pillars” that remain between the cavities, is all the more necessary as the over-lying ground has to be maintained for agricultural use and buildings.
