Published 22 June 2010
693.5 m – this depth was reached by PeBeKa’s employees who are sinking ventilating, downcast SW-4 shaft for Polkowice-Sieroszowice mine. 525.5 m is left to be still sunk because this shaft will be 1,219 m deep at 7.5 m internal diameter. SW-4 is a strategic investment for KGHM Polska Miedź S.A. Thanks to this project it will be possible to make copper ore deposit available and start extraction in so-called Głogów Głęboki Przemysłowy area.
What’s important till now the works are proceeding promptly and without any serious complications and disruptions.
A new stage of the construction has already begun. The shaft has been sinking while using ground freezing method which is PeBeKa’s identification sign. Thanks to ground freezing (till depth of 650m) it was possible to drive the shaft in water flooding quaternary and tertiary formations and in middle mottled sandstone. Tubbing with concrete jacket was used till the level of 665.2 m in the shaft. Further part of SW-4 shaft will be sunk in concrete and reinforced lining whereas coat lining will be used on salt section in order to strengthen rings with arch timbering.
Because of water threats and obligatory regulations developing drainage system in deep shaft was needed to leave freezing zone. That’s why PeBeKa’s engineers have used inventive drainage system based on using a lower, not liquidated part of exploratory–control-freezing borehole M-38. Its task is to get water from the bottom of sinking shaft to pit bottom’s excavations. On required levels borehole will be available and carried out through technological cavities that are made from the shaft during sinking (the first cavity was made on level of 636m).