Technical Evaluation of Concrete Lining in Mine Shafts at the Upper Kama Salt Deposit

The mine shafts in the salt (unwatered) rock mass at the Upper Kama deposit are mostly lined with cast-in-place concrete and reinforced concrete, which should ensure the required load-bearing capacity and water impermeability in host rocks in creep. The long-term observations of the shaft lining in operation revealed some typical patterns of failure induced by the rheological properties of salt rock mass under the action of rock pressure. The technical evaluation of the lining and reinforcement of mine shafts is an integrated checkup procedure including measurements of fractures and areas of corrosive zones/rock falls; updating of actual geometrics of lining from laser measurements; determination of residual strength of lining; mathematical modeling; estimation of integral reliability index of lining. The authors propose a procedure to categorize technical conditions of concrete lining in mine shafts in operation in salt-bearing rock mass in creep. The application of the procedure is described, and the conclusions on the package of repair activities are drawn.