College of Mining, NUST MISIS, Moscow, Russia:

M. S. Pleshko, Professor, Doctor of Engineering Sciences, pleshko.ms@misis.ru

Investment Project Management Department, Norilsk Nickel, Moscow, Russia:
A. A. Davydov, Head of Integrated Skalisty Mine Development Design Office

FAI Glavgosexpertiza, Moscow, Russia:
Yu. A. Silchenko, Deputy Head of Industrial, Nuclear and Radiation Safety Expertise Department, Candidate of Engineering Sciences

Thyssen Schachtbau GmbH, Mülheim an der Ruhr, Germany:
O. S. Kaledin, Head of Department of Russia and CIS Countries, Doctor of Engineering Sciences

The feature of shaft SKS-1 in Skalisty mine is its length more than 2 km and high horizontal stresses exceeding vertical stresses in rock mass. According to stress measurements on levels 1700–1900 m within Skalisty mine field, the maximal tectonic horizontal stresses are 65–70 MPa and orient approximately east to west while the gravitational vertical stress is 45–50 MPa. The horizontal to vertical stress ratio reaches 1.4 with increasing depth. The effective normative and technical documentation lacks design standards for shaft in such geomechanical conditions. For this reason, the shaft lining design was based on the dedicated specifications, appropriate structural concept and resource-saving technology of lining with advanced temporary lining with reinforcement. The deep shaft sinking was accompanied by scientific supervision and stress–strain monitoring in rock mass–lining system. It is found that transition to the permanent lining-with-sinking flow chart allows essential stress relief in the shaft rock mass prior to setting of main lining. Asymmetry of load intensity and permanent lining straining, as expected with regard to actual natural stress state of rock mass is observed along the cross-section of the shaft. Within 60–190 days after setting of permanent lining, straining has stabilized, which is reflective of operational integrity of the proposed lining design. Thus, the adopted engineering solutions improved integrated safety of the shaft sinking.

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