ProTech Engineering LLC, Saint-Petersburg, Russia

A. I. Rysin, Head of Laboratory
I. A. Otkupshchikova, Cat I Engineer, otkupschikova2015@gmail.com
A. S. Nurtdinov, Expert

ProTech Engineering LLC, Saint-Petersburg, Russia¹ ; Lomonosov Moscow State University, Moscow, Russia²

A. M. Lebedeva, Cat I Engineer¹, Post-Graduate Student²

The influence of the occupancy of stopes with backfill on the stability of rib pillars in salt rock mass is studied using different methods. The experience of backfill application at mineral deposits is reviewed. The experimental design of uniaxial compression testing of a standard cylindrical salt sample in the condition of compression by backfill mass at different degrees of occupancy of stopes with backfill material is developed. The tests are carried out with two types of backfill materials: broken rocks and salt waste at the degree of occupancy of stopes with the backfill from 50 to 100 %. The investigation finds out that the backfill starts exerting a substantial effect on the final strength of the test sample at the 50 % occupancy in the lab-scale test and at the 100 % occupancy in the numerical experience. The modulus of deformation remains constant in all tests and at all degrees of occupancy of stopes, and this means that the backfill has no influence on the rigidity of the supporting system. Modeling reveals the connection of the weak influence with the insufficient compaction of the backfill—the supporting effect of the backfill only appears at the high level of the stope occupancy with the backfill as a result of compaction of the backfill material. Aimed to enhance efficiency of backfilling, the method of temper and other process solutions are proposed. Finally, the conclusion is drawn on the need of revising the calculation of rib pillar heights as the present-day engineering procedures calculate loading exerted on rib pillars with backfill with a coefficient which increases stability of rocks, which is confirmed neither by practice nor by theoretical research.

1. Zubov V. P., Kovalskiy E. R., Antonov S. V., Pachgin V. V. Improving the safety of mines in developing Verkhnekamsk potassium and magnesium salts. MIAB. 2019. No. 5. pp. 22–33.
2. Baryakh А. А., Smirnov E. V., Kvitkin S. Yu., Tenison L. O. Russian potash industry: Issues of rational and safe mining. Gornaya Promyshlennost. 2022. No. 1. pp. 41–50.
3. Demenkov P. A., Basalaeva P. Regularities of brittle fracture zone formation in the zone of dyke around horizontal mine workings. Eng. 2025. Vol. 6, Iss. 5. ID 91.
4. Baryakh A. A., Gubanova E. A. On flood protection measures for potash mines. Journal of Mining Institute. 2019. Vol. 240. pp. 613–620.
5. Rybak Ya., Khayrutdinov M. M., Kuziev D. A., Kongar-Syuryun C. B., Babyr N. V. Prediction of the geomechanical state of the rock mass when mining salt deposits with stowing. Journal of Mining Institute. 2022. Vol. 253. pp. 61–70.
6. Lomakin I. S., Tsayukov A. A., Evseev A. V. Physical and mathematical modelling of rib pillar deformation and failure processes. Vestnik Permskogo federalnogo issledovatelskogo tsentra. 2021. No. 1. pp. 47–53.
7. Rylnikova M. V., Esina E. N., Sakharov E. M., Berger R. V. Regularities in geodynamic phenomena in mining deep-lying potassium–magnesium salt deposits with complex structure. Gornaya Promyshlennost. 2023. No. 1. pp. 89–94.
8. Rylnikova M. V., Berger R. V., Yakovlev I. V., Sakharov E. M. Classification of backfill mining systems for underground mining of salt deposits. Gornaya Promyshlennost. 2024. No. S5. pp. 64–70.
9. Yubero M. T., Olivella S., Gens A., Bonet E., Lloret A. et al. Analysis of the process of compaction movements of deposits of crushed salt tailings. Engineering Geology. 2021. Vol. 293. ID 106290.
10. Belyakov N. A., Belikov A. A. Prediction of the integrity of the water-protective stratum at the Verkhnekamskoye potash ore deposit. MIAB. 2022. No. 6-2. pp. 33–46.
11. Kopylov I. S., Kovin O. N., Goldyrev V. V., Maleev E. E., Bryukhov V. N. Main factors of mining-geological and environmental risks in the territory of Verkhnekamsky potassium salt deposit. Geoecology, Engineering Geodynamics, Geological Safety (Pecherkin’s Lectures) : Proceedings of International Scientific and Practical Conference Dedicated to the 90th Anniversary of Professor I. A. Pecherkin. Perm : Permskiy gosudarstvennyi natsionalnyi issledovatelskiy universitet, 2021. pp. 268–289.
12. Volchikhina A. A., Vasileva M. A. Development of equipment and improvement of technology for inertial thickening of backfill hydraulic mixtures at the final stages of transportation. Journal of Mining Institute. 2025. Vol. 271. pp. 168–180.
13. Vasileva M. A., Volchikhina A. A., Morozov M. D. Re-backfill technology and equipment. MIAB. 2021. No. 6. pp. 133–144. DOI: 10.25018/0236_1493_2021_6_0_133
14. Kovalskiy E. R., Gromtsev K. V., Petrov D. N. Modeling deformation of rib pillars during backfill. MIAB. 2020. No. 9. pp. 87–101.
15. Baryakh A. A., Tenison L. O. Justification of engineering safety criteria for undermining of water-proof layer in the Upper Kama Salt Deposit. Gornyi Zhurnal. 2021. No. 4. pp. 57–63.
16. Rylnikova M. V., Sakharov E. M., Esina E. N. Perspective for improving the methods of fixing mine workings in salt rocks of different strength. Izvestiya Tulskogo gosudarstvennogo universiteta. Nauki o Zemle. 2023. No. 3. pp. 268–279.
17. Radchenko D. N. Improvement of underground mining technology parameters for potash salt deposits using consolidated backfill masses. Problems of Subsurface Development in the 21^st Century in the Eyes of the Young : Proceedings of the 16^th International School of Young Scientists and Specialists. Moscow : IPKON RAN, 2023. pp. 3–6.
18. Radchenko D. N., Berger R. B., Tatarnikov V. I., Zubkov P. O. Experimental study of the nature and consequences of interaction of salt rocks with hydrofilling brines during underground development of potassium salt deposits. Marksheyderiya i nedropolzovanie. 2023. No. 6(128). pp. 60–67.
19. Rakic D., Bodić A., Milivojevic N., Dunić V., Živković M. Concrete damage plasticity material model parameters identification. Journal of the Serbian Society for Computational Mechanics. 2021. Vol. 15, No. 2. pp. 111–122.
20. Al-Zuhairi A. H., Al-Ahmed A. H., Abdulhameed A. A., Hanoon A. N. Calibration of a new concrete damage plasticity theoretical model based on experimental parameters. Civil Engineering Journal. 2022. Vol. 8, No. 2. pp. 225–237.
21. Vilppo J., Kouhia R., Hartikainen J., Kolari K., Fedoroff A. et al. Anisotropic damage model for concrete and other quasi-brittle materials. International Journal of Solids and Structures. 2021. Vol. 225. ID 111048.
22. Wu Z., Zhang J., Fang Q., Yu H., Haiyan M. Mesoscopic modelling of concrete material under static and dynamic loadings: A review. Construction and Building Materials. 2021. Vol. 278. ID 122419.
23. Gabaraev O. Z., Garifulina I. Yu., Zasseev I. A., Berezov A. K. Influence of massive parameters on the degree of compensation of the breed book. Natsionalnaya assotsiatsiya uchenykh. 2021. No. 73-1. pp. 12–15.
24. Kovalskiy E. R., Gromtsev K. V. Development of the technology of stowing the developed space during mining. Journal of Mining Institute. 2022. Vol. 254. pp. 202–209.
25. Sharafutdinov R. F. Regulatory provisions for determining parameters of nonlinear mechanical behavior in hardening soil models. Construction and Geotechnics. 2023. Vol. 14, No. 1. pp. 29–42.
26. Parvaneh S. M., Foster C. D., Chi S.-W. A hardening/softening viscoplastic model for largedeformation of soil. International Journal for Numerical and Analytical Methods in Geomechanics. 2022. Vol. 46, Iss. 10. pp. 1895–1918.
27. Sentyabov S. V. Mining system with backfilling for thick steeply pitching ore bodies in the conditions of high stress state of the rock mass at great depths. Izvestiya vuzov. Gornyi zhurnal. 2025. No. 1. pp. 17–28.
28. Kang Y., Fan J., Jiang D., Li Z. Influence of geological and environmental factors on the reconsolidation behavior of fine granular salt. Natural Resources Research. 2021. Vol. 30, No. 1. pp. 805–826.
29. Kongar-Syuryun Ch. B., Faradzhov V. V., Tyulyaeva Yu. S., Khayrutdinov A. M. Effect of activating treatment of halite flotation waste in backfill mixture preparation. MIAB. 2021. No. 1. pp. 43–57.
30. Belikov A. A., Belyakov N. A. Method of numerical modeling of rheological processes on the contour of single mine working. MIAB. 2024. No. 1. pp. 94–108.
31. Sukkarak R., Likitlersuang S., Jongpradist P., Jamsawang P. Strength and stiffness parameters for hardening soil model of rockfill materials. Soils and Foundations. 2021. Vol. 61, Iss. 6. pp. 1597–1614.
32. Liu W., Zhang X., Li H., Chen J. Investigation on the deformation and strength characteristics of rock salt under different confining pressures. Geotechnical and Geologic al Engineering. 2020. Vol. 38, Iss. 6. P. 5703–5717.
33. Kraipru K., Fuenkajorn K., Thongprapha T. The effect of transverse isotropy on the creep behavior of bedded salt under confining pressures. Mechanics of Time-Dependent Materials. 2024. Vol. 28, Iss. 4. pp. 2879–2897.
34. Lipnitsky N. A., Ogorodnikov R. G., Ustinova Ya. V. Simulation modeling of underground blending warehouse operation at structurally complex salt deposits. MIAB. 2023. No. 1. pp. 142–158.
35. Miao S., Wang M. L., Schreyer H. L. Constitutive models for healing of materials with application to compaction of crushed rock salt. Journal of Engineering Mechanics. 1995. Vol. 121, Iss. 10. pp. 1122–1129.
36. Konstantinova S. A., Gilev M. V., Zaltszeyler O. V. Method of evaluation of relative reaction of fill mass in its interaction with mine working enclosing rocks. Patent RF, No. 2204716. Applied: 26.06.2001. Published: 20.05.2003.