GEOBRUGG, Moscow, Russia:

A. Yu. Barinov, Chief Executive Officer, Candidate of Geographical Sciences
A. G. Filatov, Managing Director

College of Mining, NUST MISIS, Moscow, Russia:

V. A. Eremenko, Director of Research Center for Applied Geomechanics and Convergent Technologies in Mining, Doctor of Engineering Sciences, Professor of the Russian Academy of Sciences, prof.eremenko@gmail.com

Polar Division, Nornickel, Norilsk, Russia:

A. A. Bazin, Leading Specialist

Reinforcement of underground excavations is the key mission of any support meant for reducing risk of rock falls. Two basic functions of rock surface support in mines are load distribution in the system of rock bolts and retention of small rock falls (sags) between rock bolts. Rock mass is reinforced thereat, and resistance of rocks to failure and loosening (weakening) is improved. Mines all over the world apply surface supports but down to date there are no regulated guidelines on the most efficient support design for specific conditions, for instance, deformable and rockburst-hazardous rocks. A ground support system is selected based on the analyses of safety and cost factors, namely, load-bearing capacity, operating availability, expediency, work content of installation, loads (static or dynamic), etc. This article describes pilot trials of high-tensile steel wire mesh MINAX with wire diameter of 3 and 4 mm in rockburst-hazardous mines Kirov and Taimyr. Ground support design under conditions of high deformability and rockburst hazard is implemented as selection of optimum parameters with regard to energy absorption capacity per unit area of support. The research aimed to evaluate: MINAX mesh efficiency on the backs and side walls of excavations; work content and rate of MINAX mesh installation using special nozzle MESHA and Sandvik DS-411 rock reinforcement drillrig; effect of blasting on the mesh integrity; MINAX corrosion stability in mines; expediency and economic effect of the mesh. The effect of the mesh application in the pilot tests on three sites in two underground mines was beneficial: no rupture, separation or tearing-off of the mesh was observed after blasting; flexible chain links were insensitive to blast waves; the yielding and high-tensile mesh had high energy absorption capacity; light-weight MINAX mesh was easy to support and cut into separate sheets by reinforced scissors; the mesh was easily shotcreted; it was galvanized to protect from corrosion; the tensile strength of the wire mesh, for instance, MINAX 80/4, reached 2.3 t, which was two times higher than the ultimate tensile strength of the weld wire mesh with diameter of 5.6 mm. It is recommended to use high-tensile mesh MINAX in permanent, development, temporary and stoping excavations in highly stressed or weakened block rock mass in underground mining of ore deposits in the Norilsk Region, Yakutia, Khabarovsk Territory, Gornaya Shoria, Khakassia, Kola Peninsula, Ural, etc.

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