VENTILATION SHAFT NOP II CONNECTED TO THE TUNNELS OF THE VELENJE COAL MINE

The challenge of the generation which has successfully continued the 142-year tradition of coal mining in the Šalek Valley is slowly entering its final phase. Based on the domestic technological know-how and mining expertise, we have managed to excavate a 393-metre deep shaft NOP II. In the morning of 4 December, on the feast day of Saint Barbara, the patron saint of miners, we made the breakthrough and connected the underground system of tunnels of the Velenje Coal Mine with the vertical shaft and the surface. The new facility will be used for ventilation of mine tunnels and is of exceptional importance for further production as well as improving the environmental standards in the valley. The works on the shaft, performed by the subsidiary RGP, are expected to be finalised in 2019. The project is supervised by company PV Invest.

“A new, major milestone is being reached today in the rich history of the Velenje Coal Mine, which all of us have created together, because it is a result of cooperation of mining and construction experts and electrical, mechanical and project engineers. It is the challenge of our entire generation,” director general of mine operator Premogovnik Velenje Ludvik Golob told the ceremony. “We will continue to take on new tasks, sell our know-how and skills and, most importantly, have the wish and ambition always to be better.”

 

The construction of shafts has marked the entire history of the Velenje Coal Mine. An inspection shaft, which was expected to take over the role of a ventilation shaft, represented the first construction work in the mine, marking the beginning of the opening of the Škale Pit. The first shaft was named after Rudolf, the Crown Prince of Austria, followed by many others – the Franz Joseph shaft, the Crown Prince Rudolf ventilation shaft, the Glinšek ventilation shaft. The Preloge transport shaft and the ventilation shafts Preloge, Pesje and Hrastovec were built in the post-war period.

 

Lignite reserves in the Škale Pit were exhausted soon after, making the future of the Velenje Coal Mine largely dependent on reserves in the Preloge Pit. The first replacement facility was the Šoštanj 1 ventilation shaft, while mechanical excavation works started in January 1980 on a transport shaft, which was given the official name Nove Preloge transport shaft and which was the tenth shaft of the Velenje Coal Mine. The shaft was finalised four years later, while the final operational permit for the facilities and equipment was obtained in July 1987. The 416-metre deep shaft still serves today as the main transport shaft for miners and material.

“Construction of vertical underground transport paths – shafts –is among the most demanding underground works in mining. The depth of the facility, restricted working space under the surface and specific geo-mechanical properties of the rock in which the facility is being built make such construction particularly demanding. It is a mining facility in which the majority of the activity takes place under ground,” explained director of company RGP Marjan Hudej. “Today, when we have all possible modern technologies at our disposal, it is hard to imagine how our predecessors were building vertical shafts a hundred and more years ago. What is especially important for us is that the facility has been built well and without accidents and that we have gained a major reference which has also been recognised abroad.”

Classical construction methods were used for the ventilation shaft NOP II, including the application of pulleys, headframe and work and winding platform. A total of 21,625 m3 of rock was excavated and transported to the surface with special technological equipment. We installed more than 585 tonnes of steel arch supports, 25,800 m2 of rebar and more than 4,800 m3 of concrete. The pouring of concrete at the extreme depths was a major technological challenge, which was successfully tackled. The final internal diameter of the facility is 6.15 metres.

The ventilation shaft NOP II will be in use until the closure of the Velenje Coal Mine. “It provides the most optimal solutions, with which the existing facility will serve the purpose of ventilation of the pit as part of solving of the issue of the environmental impact of the Pesje Pit and safety parameters related to ventilation of the pit – the start of its operation will contribute to the gradual solving of the problem of odours in the area of the Jezero Tennis Centre and the ventilation shaft in the town of Šoštanj,” added the director general of Premogovnik Velenje.

You can find a video clip showing the breakthrough from the mine tunnels into the shaft on this link:https://wetransfer.com/downloads/88c23515c042b9cc6e32fb6f70e1456420171204104222/3f26f74deb70b6aee421e132fd4db17020171204104222/a6ce25?utm_campaign=WT_email_tracking&utm_content=general&utm_medium=download_button&utm_source=notify_recipient_email