Mapping of evaporite deformation in a potash mine using ground penetrating radar: Upper Kama deposit, Russia

Abstract

Abstract Understanding the deformation processes in potash mines is very important for safe mining, planning the methods of extracting the orebody, and the prevention of catastrophic water inflow. A variety of deformational structures are present in the Upper Kama potash deposit. Folding is a dominant and most common form of deformation of ductile evaporites (herein also referred to as salts). Brittle deformation occurs rarely but is of more significance from the perspective of mine safety because fractures affect the supporting capability of mine pillars and can provide passageway for water inflow. Continuous common offset ground penetrating radar (GPR) data were acquired in the potash mine operated by the Joint Stock Company (JSC) “Silvinit” to investigate a set of pre-existing fractures and related deformational structures. Open fractures, faults and folds were mapped using 2-D and 3-D GPR techniques. Detection of millimetric scale fractures was available due to high salt/air dielectric properties contrast and low background noise within uniform salt rock. FK filtering significantly improved fracture detection and imaging. A spatial model of one set of fractures was created using 3-D GPR imaging. Migration was applied to GPR data to obtain the true geometry of the strongly folded salt beds. The results of studies showed that GPR is capable of providing valuable information about deformation within the evaporite formations of the Upper Kama potash deposit.