Raw material has been mined at the Loja hard stone plant since the beginning of the 20th century. Due to the unique material quality, the extracted raw material is used throughout Austria primarily for high-quality surface layer in road, railroad and airport construction. The hard rock extracted in the open pit by means of drilling and blasting technology is processed in several crushing stages. After the secondary crushing stage was renewed in 2013 and the primary crushing stage in 2015 with processing technology from Sandvik and has proven itself for more than 25 000 operating hours, the construction of the new wet separation plant (NTA) has now been implemented. The foundation stone for this was already laid on November 24, 2020 with the signing of the contract.
The joint processing operation, which was developed in a coordination process lasting several months, resulted in a supply contract for a total of three CH840i Hydrocone crushers, a CV217 vertical impact crusher, three SJ screens from the Peak Screening series, and a total of five SP feeders for process support. Construction of the plant began with site creation in October 2020, during which time approximately 450 000 tons of rock were removed from site. Starting in January 2021, preparatory work on the haul-offs (upgrading and expansion to 700 t/h) and the interim storage facility was carried out as part of the winter maintenance of the existing facilities. The solid construction work started in March 2021 and continued until November 2021. Approximately 8500 m³ of reinforced concrete was produced on site and installed by the companies Bernegger and Dywidag. Plant and structural steel erection began in August 2021 in the basement and in September 2021 in the loading area of the plant.
Following the departure of the solid construction crews, erection of the main plant was carried out from November 2021 over the challenging Corona winter. Approximately 1000 tons of steel structure, 600 tons of chutes and the plant equipment were erected by June 2022. From January 2022, electrical and piping erection began in parallel with the plant erection. For the new NTA 2.0 with a connected load of 3080 KW, a redundant power supply via the medium voltage level 20 KV was installed. In June 2022, the cold commissioning of all individual units began. In total, around 350 motors, 90 of which can be controlled via frequency converters, were started, adjusted and tested.
The first material runs started on 28.07.2022. By September 2022, the plant was shut down and the screening lines and processes were improved to such an extent that the products meet the standard requirements. Since September, the plant has been running regularly at the desired plant capacities. Further optimization processes of the plant are running in parallel with the completion of the assembly in secondary areas. The completion of the completion and further process-technical optimization of the respective required qualities and quantities will still occupy the entire team in the next few months. But here too, all those involved are looking calmly to the future and are sure that, with this very good and professional cooperation, the remaining work will soon be completed.
A total of 90 people came to the Customer Day at Loja in perfect weather. The event was moderated and opened by Mr. Alois Raffelsberger, Sales Manager Austria at Sandvik. After greetings by Mr. Bernegger, the participants were able to follow the development of the Hartsteinwerk Loja Betriebs GmbH and background information on the NTA 2.0 project in two presentations by Dipl.wirt.Ing. Günter Wolfgang Hirsch and DI Stefan Kirnbauer. Following the presentations, the participants then had the opportunity during a plant tour to take a close look at the modern processing plant and to generate their own impression of the technical progress and dimensions.
The second part of the day was filled with presentations from Sandvik on current developments in SRP. Jan Martens, Product & Application Specialist for Roller Crusher, gave an insight into the upcoming developments and product innovations in the field of hybrid roller crushers from Sandvik. VP and Head of Digital Solution at Sandvik Rock Processing, Petra Sundström, informed the audience about the current product developments around “SAM – Your Always on Digital Assistant” and made them curious about the future. In particular, the networking of near real-time machine data, e-commerce solutions and a communication platform for interaction between users of the digital service represents interesting digital solutions for a rapidly changing future.