Belaruskali, Soligorsk, Belarus:

I. I. Golovaty, Chief Executive Officer
A. B. Petrovsky, Deputy Chief Engineer of Mining Operations

Institute of Mining, Soligorsk, Belarus:
V. A. Gubanov, Chief Researcher, Doctor of Engineering Sciences
A. L. Polyakov, Director, Candidate of Engineering Sciences, sigd@list.ru

The original project of mining at the Starobin potash salt deposit assumed top-downward extraction of reserves from potash seam III composed of fours sylvinite layers, starting from upper later IV. However, because of organizational and technological reasons, the project sequence of mining was put aside, mining started from the lower-lying layers, and undermined layer IV holding nearly 100 Mt of potash reserves was abandoned. At the present time, 25 years later, it is required to find and justify safe mining technology for abandoned undermined sylvinite layer IV. In order to reach the objective, specialists of the local Institute of Mining were engaged into creative cooperation with Belaruskali’s practitioners. The studies began in 2011 and had two stages. At the first stage, by means of exploratory headings (total length of 600 m), rock mass disturbed by the lower-lying mine was examined, and feasibility of safe mining of sylvinite layer IV was determined. At the second stage, again using exploratory headings (total length of 650 m), detailed geomechanical research was carried out, which identified optimal zones for developing entries and subsequent efficient extraction of the abandoned reserves from layer IV. Based on the accomplished research, the mining technology for the sylvinite layer was developed. During preparation of an extraction panel for mining, special-purpose headings were driven: haulage, conveyor, ventilation and erection. Concurrently, face area support was selected as K-12 support manufactured in Belarus. In the course of the technology application (round a year), more than 1.3 Mt of ore have been produced and the first extraction panel has been worked out.

1. Volkov A. B. Method for two-layer extraction of thick complex-structure mineral seam. Patent BY7653, E21C 41/00. Applied: 01.04.2002. Published: 20.12.2005.
2. Semenova I. E., Zemtsovskiy A. V., Pavlov D. A. Monitoring of state of underground mine excavations in “Oleniy Ruchey” deposit. Monitoring of natural and technogenic processes during mining works : collection of proceedings of scientific-technical conference. Saint Petersburg : Renome, 2013. pp. 280–289.
3. Usanov S. V., Mel’nik V. V., Zamyatin A. L. Monitoring rock mass transformation under induced movements. Journal of Mining Science. 2013. Vol. 49, No. 6. pp. 913–918.
4. Ruchkin V. I., Zheltysheva O. D. The effect of technogenic load on the dynamics of stress-strain state of rock mass. Problemy nedropolzovaniya. 2015. No. 1. pp. 26–31.
5. Balek A. E., Sashurin A. D. Problem of evaluation of natural stress-strain state of rock mass during development of mineral resources. Gornyi informatsionno-analiticheskii byulleten. 2016. No. 21. pp. 9–23.
6. Sashurin A. D., Balek A. E., Panzhin A. A., Usanov S. V. Innovative technology for diagnosis of geodynamic activity in geological media and safety assessment of subsoil use objects. Gornyi Zhurnal. 2017. No. 12. pp. 16–20. DOI: 10.17580/gzh.2017.12.03
7. Kodama J., Miyamoto T., Kawasaki S., Fujii Y., Kaneko K. et al. Estimation of regional stress state and Young’s modulus by back analysis of mining-induced deformation. International Journal of Rock Mechanics and Mining Sciences. 2013. Vol. 63. pp. 1–11.
8. Khani A., Baghbanan A., Norouzi S., Hashemolhosseini H. Effects of fracture geometry and stress on the strength of a fractured rock mass. International Journal of Rock Mechanics and Mining Sciences. 2013. No. 60. pp. 345–352.
9. Mohtarami E., Jafari A., Amini M. Stability analysis of slopes against combined circular–toppling failure. International Journal of Rock Mechanics and Mining Sciences. 2014. Vol. 67. pp. 43–56.
10. Sainoki A., Mitri H. S. Dynamic behavior of mining-induced fault slip. International Journal of Rock Mechanics and Mining Sciences. 2014. Vol. 66. pp. 19–29.
11. Figueiredo B., Cornet F. H., Lamas L., Muralha J. Determination of the stress field in a mountainous granite rock mass. International Journal of Rock Mechanics and Mining Sciences. 2014. Vol. 72. pp. 37–48.
12. Gubanov V. A., Puzanov D. A., Mozgovenko M. S., Erokhin K. A., Podlesnyi et all. Investigation of rock pressure manifestations in development and production workings by mining of underworked and abandoned reserves in the IV sylvinite layer and inter-panel pillar of the experimental longwall face no. 11-3 on the horizon – 620 m of the Third mine group of JSC “Belaruskali”. Gornaya mekhanika i mashinostroenie. 2017. No. 2. pp. 5–18.
13. Gubanov V. A., Puzanov D. A., Mozgovenko M. S., Mikheev I. A. Choice of points of emplacement of development workings at their driving in protective intercolumn pillars in 25-30 years after carrying out the winning operations in lavas worked-out contiguously. Gornaya mekhanika i mashinostroenie. 2014. No. 1. pp. 43–47.
14. Gubanov V. A., Puzanov D. A., Mozgovenko M. S., Yerokhin K. A., Podlesny I. A., Petrovsky A. B., Dolgikh A. S. Justification of ways of carrying out and maintenance of experimental longwall development workings for underworked IV sylvinite layer extraction and written-off reserves in inter long-pillar horizon pillars –620 m of the 3 Mining department of JSC “Belaruskali”. Gornaya mekhanika i mashinostroenie. 2016. No. 4. pp. 5–17.