Nornickel’s Polar Division is now working to launch a new rock bolting technology at its mines. It will significantly improve safety and accelerate shaft sinking while reducing its cost. By 2020, the technology will be introduced across all mining units of the Polar Division. The project’s total capex will exceed RUB 2.1 bn.
The technology is now being piloted at Taimyrsky and Komsomolsky Mines, which have received four Sandvik DS411 (Finland) rigs for rock bolt installation.
Rock bolt is an artificial structure designed to prevent rockfall inside the mine workings. The bolting technology currently in use is rather time-consuming as it takes at least 12 hours for concrete mix applied as part of the process to harden enough. On top of that, the technology requires manual labour and human presence in hazardous unsupported areas of the mine.
The new technology makes mine bolting safer since it eliminates the need for human presence in hazardous areas while significantly accelerating the operations: the special mix used for bolting purposes hardens in only a few minutes.
The new technology is expected to use resin-grouted rock bolts, made of a combination of quick-hardening polyester resin and a metal anchor. Resin grouted bolts provide secure polyester resin adhesion to the reinforcement bar and the rock contour of borehole walls (a hole in mine working of up to 5 m in depth) creating a protective stiffened layer that can effectively sustain rock pressure.
Using quick-hardening mixes will reduce the time required to complete a shaft sinking cycle by 25%. Mechanised bolting solutions will also decrease labour input by 14% on average. Lower bolting costs across Polar Division’s mines will save the Company RUB 668 m in 2017–2020.
At the moment, the Company trains hole drillers in using the new technology. In addition, the manufacturer is supervising the testing of the machines and fine-tuning of the mechanised bolting technology. Training and tests will take two months. After that, the new bolting technology will be implemented in the underground stoping and site preparation areas of the active mine faces.
By 2020, the new bolting technology is expected to be introduced, on a phased basis, across all mining units of Nornickel’s Polar Division with more than RUB 2.1 bn allocated for this purpose.