Evaluation of Dissolution Interchamber Pillar Salt Mines in Their Flooding (on the Example of the Mine SKRU-2 VKMKS)
Mining Institute of the Ural Branch of the Russian Academy of Science, Russian Federation
EVALUATION OF DISSOLUTION INTERCHAMBER PILLAR SALT MINES IN THEIR FLOODING (ON THE EXAMPLE OF THE MINE SKRU-2 VKMKS)
Konosavsky P. K., Potapov A. A., Filin R. A.
The paper discusses the methodological issues of quantitative assessment of dissolution interchamber pillar salt mines when the flooding waters of post-salt strata is strongly undersaturated at Silvino for example, the emergency flooding of the mine SKRU-2 in the Verkhnekamskoe potash-magnesium salts.
To assess the dissolution, a specialized numerical filtration-migration model was developed, implemented using the software package PM8 (Processing Modflow version 8 – authors Wen-Hsing Chiang, W. Kinzelbach). The implementation of numerical calculation of the process of dissolution of sylvite was carried out in the framework of the model the mass exchange between the "flowing and stagnant pores" in a medium with double porosity taking into account the kinetics of the mass transfer equation of the first order. Numerical calculation of damage (degradation) to interchamber cells was performed based on the calculated value of the current (at each time step k) salt concentration in each calculation block. it is the resulting value obtained in the solution of the total problem of transport of the solute and dissolution. At the same time, the simulation of such migration process at each time step in the Mt3DMS module of the PM8 package is implemented in two stages: 1) the solution of the problem of the substance transfer within the entire model and then 2) the simulation of the dissolution itself ("mass transfer between stagnant and flowing pores"). Hydrochemical calibration of the numerical filtration-migration model at the initial assessment station could be performed only based on the results of chemical analyses of brines taken at the point of their pumping at the water edge in the Eastern brine collector 4 of the ONS "Vostok".
Depending on the considered scenarios of the intensity of the mine flooding, the sizes of the zones of significant degradation of the pillar will be different. In conditions of slow flooding (570 m3/h), the size of the zone of significant degradation of interchamber pillar (more than 0.1 m on each wall of the chambers) will be smaller values in comparison with the most intense flooding (7 500 m3/ h). in this case, within the specified zone, the absolute value of degradation of pillar in slow flooding will be much greater than in intensive flooding.