Original design and installation of artificial bottom structure - a patent-worthy invention

Conducting works below the bottom of the shaft, at 980 m - i.e. below the existing infrastructure in the shaft - requires the active part to be separated from the part where the project will be carried out.  The installation of an artificial bottom was therefore a necessity, as it makes it possible and safe to carry out work below the bottom of the shaft and does not interfere with the operation of the mine shaft hoists installed in the shaft.

“Before starting the project, we had assumed that the interference with the shaft lining should be as limited as possible. Przedsiębiorstwo Budowy Szybów presented the mine with an innovative solution that met our expectations,” says Łukasz Tobiczyk, technical director of the Borynia Section.

The design requirements were unusual and had not been used before.

“We developed an original design of an artificial bottom, which was made of three layers of high-strength nets supported by steel cables, attached to braking elements.  Then, with the participation of the AGH University of Science and Technology in Kraków, we carried out the relevant tests to enable the construction of such a structure.  The obtained parameters confirmed that our idea is a suitable technical solution for the installation of an artificial bottom structure in such a small space under the existing structures built in the bottom of shaft II.  We therefore recommended this solution,” says Marcin Mieszczak, President of the PBSz Management Board.

The construction of the artificial bottom was completed in June this year, and in October, Przedsiębiorstwo Budowy Szybów received a patent document for the construction and installation of the artificial bottom of the shaft.

The construction of the artificial bottom of the shaft made it possible to implement the project related to the deepening of Shaft II, which was divided into three stages.  The first was the excavation of the access pit to the hoisting machinery chamber and the excavation of the process pit at a depth of 1,003 m. These works were carried out by the crews of the PBSz Horizontal Works Department.  The second stage is the execution of preliminary works in the vertical excavation, which are also carried out by PBSz employees - this time from the Shaft Works Department.  The works consist of: connecting the excavation of the hoisting machinery with the bottom of Shaft II, the making of a complete cross-section of this excavation - intended for the installation of the hoisting machinery, and the excavation of a section of the shaft pipe between the inlet to the hoisting machinery chamber and the technological level located 18 metres below.  Once this work has been completed, only the third stage remains. The third stage is the excavation of a shaft pipe between the technological level and the target level of 1,120 m, together with a shaft section for the installation of a rope reversing station and shaft bottom drainage facilities at a depth of approximately 1,150 m.  It should be noted that during the third stage, the shaft has to be refitted from the 838 m level to the artificial bottom level, and the shaft has to be outfitted in the newly excavated shaft section and equipped with a number of necessary components for the operation of the hoisting installation up to the 1,120 m level.

“The cooperation with PBSz during the project is exemplary.  The employees have the technical knowledge of the work to be performed and have at their disposal the right equipment to perform the tasks according to plan in an effective and safe manner,” said Paweł Goik, chief mechanic of the shaft, hoisting and surface operation equipment of the Borynia Section, adding: “I would like to see the work continue to be carried out in accordance with the adopted schedule.  It is important for us to start up and put into operation the extended mining shaft hoist to the level of 1,120 m in the shortest possible time.”

The project is scheduled for completion in 2027.