Application of automated integrated geotechnical monitoring system in support of rib pillars of large cross-section and length in the Iletsk rock salt field

Abstract

The Iletsk rock salt field development for 200 years has been carried out is a disordered manner. Alongside open pits, a few underground mines were operated (Elizavetinskaya, Mariinskaya) but not for long and were flooded soon. The flooding of those mines and Mine No. 1 later on was explained by their occurrence inside the top jointed and karstic salt core. Mining safety and efficiency under conditions of flooded Mine 1, as well as actual mining operations on the second and third levels of Mine 2 is ensured by means of handling some geomechanical problems. In the course of the stress–strain assessment in a rib pillar of large cross-section and extension, it was recorded that the load on the rock bolting system in the pillar grew but the deformation studies in the pillar edges showed no straining. The obtained results make it possible to draw a conclusion that the existing rock bolting system performs the duty: it distributes load between rock bolts and holds small pieces of rock salt between the rock bolts in case of inrush. The former function is especially critical for the reliable operation of the whole support system in the conditions of plasticity. The average increment in the load applied to the rock bolting system is estimated as 120 kg per month, or 1.5 ton per year. The integrated geotechnical monitoring system allows recording and display of deformation and incremental loading of support in pillars. The linear patterns of the obtained data make it possible to predict the load increase and to adjust the mining process flows if necessary.