VNIIG, Saint-Petersburg, Russia:

Yu. P. Shhokin, Senior Researcher, Candidate of Engineering Sciences, kopyleva@galurgy.sp.ru

The study is concerned with the topical issues connected with the prevention of groundwater inflow in potassium mines. Five types of possible sagging of water-impervious strata–waterproof strata (WPS)–without inflow of groundwater in potassium and rock salt mines are described. The minimum size of through cracks hazardous in terms of water or brine flow from WPS to mines is estimated and analyzed. A specific emphasis is laid in water flow in crevices in swelling rocks (clay–chalky clay) typical for WPS at Starobinsk potassium salt deposit in Belarus. The experimental results on critical deformation of rocks (chalky clay, dolomite, rock salt, sylvinite) without visible fracturing are reported. According to the proposed method, comparison of these experimental data with the impermeable stratum tension strains obtained on models of equivalent materials allows judging on the presence (absence) of fracturing in undermined WPS. It is found that potassium mining by longwall method with roof caving in Soligorsk mines induces single fractures in their most hazardous echelon form in WPS (brittle dolomite layers at the interface with gypsum and calcite).

1. World mineral statistics archive. British Geological Survey. Available at: https://www.bgs.ac.uk/mineralsuk/statistics/worldArchive.html (accessed: 15.07.2018).
2. Shokin Y. P. Causes of flooding of potassium mines with ground water and brines in GDR and FDR. Gornyi Zhurnal. 1981. No. 11. pp. 58–60.
3. Olovyannyi A. G. Some Problems of Rock Mass Mechanics. Saint-Petersburg: VNIMI, 2003. 234 p.
4. Dyagilev R. A., Shulakov D. Y., Verholantsev A. V., Glebov S. V. Seismic monitoring in potash mines: observation results and development aspects. Eurasian Mining. 2013. No. 2. pp. 24–28.
5. Olovyannyi A. G. Rock Mechanics. Failure Modeling. Saint-Petersburg : IPK KOSTA, 2012. 280 p.
6. Aptukov V. N., Vaulina I. B. Geomechanical estimation of waterproof mass state in the Upper Kama basin potash deposit based on mathematical modeling methods. GIAB. 2014. No. 4. pp. 334–340.
7. Baryakh A. A., Samodelkina N. A. Water-tight stratum rupture under large-scale mining. Part II. Journal of Mining Science. 2012. Vol. 48, Iss. 6. pp. 954–961.
8. Ivars D. M., Pierce M. E., Darcel C., Reyes-Montes J., Potyondy D. O. et al. The synthetic rock mass approach for jointed rock mass modelling. International Journal of Rock Mechanics and Mining Sciences. 2011. Vol. 48, Iss. 2. pp. 219–244.
9. Solovev V. A., Aptukov V. N., Vaulina I. B. Support of mining workings in saliferous rocks. Novosibirsk : Nauka, 2017. 263 p.
10. Walton G., Diederichs M. S. A New Model for the Dilation of Brittle Rocks Based on Laboratory Compression Test Data with Separate Treatment of Dilatancy Mobilization and Decay. Geotechnical and Geological Engineering. 2015. Vol. 33, Iss. 3. pp. 661–679.
11. Royer J. J., Litaudon J., Filippov L. O., Lyubimova T., Maximovich N. 3D geostatistical modelling for identifying sinkhole disaster potential zones around the Verkhnekamskoye potash deposit (Russia). Journal of Physics: Conference Series. 2017. Vol. 879. DOI: 10.1088/1742–6596/879/1/012018
12. Bezgin A. M. Ability of gash joints to bring water in mines. Gornyi Zhurnal. 1935. No. 8. pp. 22–26.
13. Khokhlov I. V., Sherstnev N. V., Fedanov V. P., Zaitsev S. I. Coal Field Mining in the Pechora Basin. Moscow : Gosgortekhizdat, 1960. 292 p.
14. Kusakov M. M., Mekenitskaya L. I. Thickness of Thin Layers “Bound” Water. Moscow : AN SSSR, 1965. 45 p.
15. Romm E. S. Permeability of Jointed Rocks. Moscow : Nedra, 1966. 283 p.
16. Frumkin A. N., Bagotsky V. S., Iofa Z. A., Kabanov B. N. Kinetics of Electrode Processes. Moscow : Izdatelstvo Moskovskogo universiteta, 1952. 319 p.
17. Rabinerson A. I. Problems of Colloid Chemistry. Leningrad : Khimteoret, 1937. 379 p.
18. Lomize G. M. Flows in Jointed Rocks. Moscow–Leningrad : Gosenergoizdat, 1951. 127 p.
19. E. A. Kozlovsky (Ed.). Mining Encyclopedia. In five volumes. Moscow : Sovetskaya entsiklopediya, 1987. Vol. 3: Kengan–Ort. 592 p.
20. Kashkin P. N., Elinov N. P., Kashkin K. P. Microbiology. 4^th enlarged and revised edition. Leningrad : Meditsina, 1968. 367 p.
21. Novokshonov V. N., Danilova A. F., Deshkovskiy V. N., Zeytts V. E. Research of process of development of anthropogenic fractures in underworked rock massif at Starobinsky deposit. Gornyi Zhurnal. 2014. No. 2. pp. 19–22.
22. Kovalev O. V., Mozer S. P., Tkhorikov I. Yu., Sankovskii A. A. Rock mechanics problems decision algorithm for bottom layers of potash salt deposits. Journal of Mining Institute. 2014. Vol. 207. pp. 60–62.
23. Abe S. Comparison of discrete element simulations to theoretical predictions of the elastic moduli of damaged rocks. International Journal of Rock Mechanics and Mining Sciences. 2016. Vol. 88. pp. 265–272.