There are still 414 meters of the sinking left to reach a target depth of 1164 m. The investment in the new mining field Bzie-Debina will make it possible for JSW to get access to one of Europe's largest coking coal deposits.
Sinking of Bzie1 shaft was commenced in November 2010. Construction technology adopted at the beginning involved the shaft pipe in concrete lining with using initial panel housing with reinforced concrete panels. Unfortunately - as in the mining industry - it was not easy and during shaft sinking at a depth of 290 meters a far more difficult, hydro-geological conditions appeared. The sinking has been suspended for 10 months, during which the general contractor - Kopex-CML SA - made a series of works and technical measures aimed at increasing consolidation of the rock mass around the shaft. The scale of the geological disturbances that threatened further work progress in the mine forced the mine to modify the design documentation and sinking by sections based on the sequentially developed technical projects.
Instead of standard reinforced concrete panels much more robust steel panels were used in the sections of lower strength parameters of rock. For the final housing high-quality concrete was applied with much higher load resistance . At the same time they started to perform routine drilling of the well bottom to verify hydrogeological conditions of the shaft sections planned to explore. These holes were used during the sinking of the gradual dewatering and degassing of the rock mass.
- The technology used when sinking Bzie1 shaft, allowed for a smooth transition through the Dębowiec layers, the most feared due to the small hardness, strong water inroad and gas content. Changing the sinking technology also allowed to avoid costly and time-consuming method of shaft sinking by frost method. - emphasizes Gabriel Przeliorz, director of investment and development "Borynia- -Zofiówka -Jastrzębie" mine.
Achieving in the first half of November carboniferous coal-bearing strata will allow the return to the original sinking technology. Starting from755 m, the shaft will be sunk without initial housing, with a single layer of concrete.