Taimyrsky Mine Integrated Development Design Office, Norilsk Nickel Development LLC, Moscow, Russia:

D. S. Vlasenko, Chief Manager, Candidate of Engineering Sciences, VlasenkoDS@nornik.ru
I. V. Peshkov, Chief Manager

Norilsk Nickel’s Polar Division, Norilsk, Russia:
S. Yu. Shilenko, Deputy Director of Occupational and Industrial Safety

Fedorovsky Polar State University, Norilsk, Russia:
O. S. Danilov, Associate Professor, Candidate of Engineering Sciences

The main method of gathering data on rock mass quality is core description in geotechnical and operating boreholes. These data are used in design documentation, and they govern the choice of the advance direction of mining front, geometry of underground openings as well as the mine support systems and design. Norilsk Nickel has implemented an extensive drilling project at Taimyrsky Mine. The project included drilling of geotechnical (from underground tunnels) and geological (from ground surface) boreholes. The drilling procedure included core orientation and geotechnical description according to the company standard STO UKK GRR-16-2018 Detailed Geotechnical Core Description. All in all, over the period from 2018 to 2021, 101 boreholes of the total length of 6867 m were drilled, and 6815 m of core was extracted (more than 99%). The presented analysis and methodological approach to evaluation of geotechnical data gathered in drilling in Taimyrsky Mine essentially improve the quality of the acquired information. It is found that the data on rock mass jointing from exploration and exploitation boreholes are distorted and underrate the rock mass stability index. On the evidence of geotechnical drilling data, the values obtained in exploration and exploitation boreholes are adjusted and can be used in geomechanical block modeling of mineral deposits which are or going to be mined. The implemented adjustment of the exploration and exploitation drilling data allows expanding greatly the area of the acquired engineering information without its distortion.

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