VNIMI’s Kemerovo Division, Kemerovo, Russia

P. V. Grechishkin, Director, Candidate of Engineering Sciences, pv_grechishkin@mail.ru

Urgalugol, SUEK, Chegdomyn, Russia

G. L. Feofanov, Technical Officer, Candidate of Engineering Sciences
A. G. Kozlov, Chief Industrial Engineer in the Severnaya Mine

VNIMI’s Siberian Division, Prokopevsk, Russia

Ya. I. Zaytsev, Technician

At the present time, the Severnaya Mine of Uralugol prepares and extracts coal from seams V-12 and V-26. The thickness of the seams varies from 1.6 to 3.8 m, the dip angle is to 4°, and the maximum depth of mining on seam V-12 is –350 m. Coal is produced via fully mechanized longwall mining along the strike. The geological analysis of coal seams V-12 and V-26 proves the extreme inconsistency of the seam thickness and enclosing rock mass structure; the immediate roof is everywhere replaced by quar and tuffite bands; the initial geological data are insufficient for the support design for underground excavations. Considering complex and persistently varying geological conditions of the coal seams, the available Rockbolting Design Guidelines provides not always adequate design of heading, support and reinforcement of roadways in the course of their life. This article authors accomplished the research aimed to justify support designs for roadways with regard to the stress–strain behavior of coal–rock mass under conditions of seams V-12 and V-26. The article describes the mine and laboratory studies of physical and mechanical properties of enclosing rock mass, displacements at the roadway boundaries and deep in rock mass, videoimage endoscopy, geophysical studies and numerical modeling of geomechanical processes. The obtained geomechanical parameters included the strength characteristics of rocks and coal, displacements and deformation at the roadway boundaries, vertical and horizontal elastic and elastoplastic strains, full vectors of stresses and strains in rock mass surrounding the roadways, residual/initial strength ratio of coal and rocks, etc. For coal seam V-12, for the natural equilibrium arch, it is recommended to increase the arch coefficient Karch by 15–20% and to use rock bolts with yielding not less than 150–200 mm to eliminate over-load and breaking. Based on the integrated research and analysis of enclosing rock mass of coal seams V-12 and V-26 in the Severnaya Mine of Uralugol, the support designs were adjusted so that to ensure safety of roadways for the whole life of their operation.

1. Federal Code for Industrial Safety : Rockbolting Design and Use Manual for Coal Mines. Series 05. Documents on Safety, Supervision and Regulatory Activities in Coal Industry. Issue 42. Moscow : NTTs PB, 2015. 186 p.
2. Fryanov V. N., Petrova O. A., Petrova T. V. Package of problem-oriented programs for modeling formation and distribution of hazardous zones in gas-containing geo-mass. Khroniki Obedinennogo fonda elektronnykh resursov “Nauka i obrazovanie”. 2015. No. 8-9(75-76).
3. Rib S. V., Basov V. V., Nikitina A. M., Borzykh D. M. Numerical modeling of geomechanical behavior of non-uniform coal pillars by the finite element method. High technologies of mineral mining and use : Collection of scientific papers. Novokuznetsk, 2014. No. 1. pp. 123–128.
4. Yakovlev D. V., Mulyov S. N. Experience of ANGEL-M Multipurpose Geophysical Equipment Use in Coal Industry and Ore Mining. Ugol. 2014. No. 10. pp. 14–19.
5. Grechishkin P. V., Feofanov G. L., Fryanov V. N., Petrova O. A., Aushev E.V. Peculiarities of deformation of surrounding rock mass around roadways in nonuniform field of tectonic stresses in terms of coalbed B-12, Severnaya mine, Uralugol. GIAB. 2017. No. 5. pp. 255–270.
6. Grechishkin P. V., Pozolotin A. S., Zayatdinov D. F., Sharov V. N. Estimate of efficiency of two-level rock bolting at junctions in coal mines. Gornyi Zhurnal. 2015. No. 8. pp. 48–52. DOI: 10.17580/gzh.2015.08.11
7. Esterhuizen G. S., Murphy M. M., Bajpayee T. S. Analysis of Geotechnical and Support Parameters on Coalmine Entry Stability Using the Strength Reduction Method. AusRock 2014: Third Australasian Ground Control in Mining Conference. Melbourne: The Australasian Institute of Mining and Metallurgy, 2014. pp. 383–392.
8. Jianguo Zhang, Wei Yang, Baiquan Lin, Jinjing Zhang, Man Wang. Strata movement and stress evolution when mining two overlapping panels affected by hard stratum. International Journal of Mining Science and Technology. 2019. Vol. 29, Iss. 5. pp. 691–699.
9. Sherizadeh T., Kulatilake P. H. S. W. Assessment of roof stability in a room and pillar coal mine in the U.S. using three-dimensional distinct element method. Tunnelling and Underground Space Technology. 2016. Vol. 59. pp. 24–37.
10. Galvin J. M. Ground Engineering: Principles and Practices for Underground Coal Mining. Cham: Springer International Publishing, 2016. 693 p.
11. Napa-García G. F., Câmara T. R., Torres V. F. N. Optimization of room-and-pillar dimensions using automated numerical models. International Journal of Mining Science and Technology. 2019. Vol. 29, Iss. 5. pp. 797–801.
12. Mandal K. P., Das A. J., Kumar N., Bhattacharjee R., Tewari S., Kushwaha A. Assessment of roof convergence during driving roadways in underg round coal mines by continuous miner. International Journal of Rock Mechanics and Mining Sciences. 2018. Vol. 108. pp. 169–178.