Electrification – Erzberg under power
Among the vehicles of VA Erzberg GmbH, one in particular stands out: the T 236 dump truck from Liebherr with hybrid drive. Vehicles with diesel-electric drive are used all over the world with payloads of over 200 t, but in the ore deposit of the Erzberg the use in the 100 t class in combination with the overhead line system is unique. “The diesel-electric T 236 has been developed by Liebherr since 2012 and launched in 2018. One of the first prototypes has already been in use at Erzberg for further development since 2017. But it is the overall concept with the overhead line, which was included in 2019 and does not exist in this form a second time, that makes our facility unique,” says Dr. Peter Schimek, project manager of the overhead line facility. “This investment in the future has paid off, because now we will benefit in the long term from a decisive increase in productivity and a lower environmental impact in our operations.”
The overhead line system was built to enable operation with hybrid heavy-duty trucks, which can also be driven with the help of direct current collection. In contrast to conventional diesel-electric vehicles, the machinery of VA Erzberg GmbH has thus been running almost entirely in electric mode in large parts of the opencast mine since October 2021. The conventional drive is only still needed on newly created roads and at the transition to the mining area, as well as in the area of the spoil heap. Instead of 15 minutes, the vehicle needs only ten minutes for the corresponding route with overhead line system and saves around 95 % of diesel fuel. Converted, this results in a CO2 saving of about 8000 t/a as well as a 3 million l reduction in fuel consumption compared to the conventional drive.
Special projects create special demands
The tyres of the vehicles also play a significant role in the implementation of the project. Here, Bridgestone, one of the leading global suppliers of tyres and sustainable mobility solutions, supports VA Erzberg GmbH with the corresponding premium tyres as well as the associated technical services around the tyre, which ensure that the products are optimally adjusted to the various requirements. In order to implement the overall concept of the overhead line system without any problems, specific demands are placed on the vehicle and tyres, which are made up of both the special location of the ore deposit and the technical conditions of the project. “For example, it must be taken into account that the direct and high-torque drive leads to greater wear on the tyre tread and that the increased speeds also bring additional stress, which in particular has an impact on the tyre temperature and thus on the service life of the tyre,” says Dr. Peter Schimek.
“In order to select the appropriate tyre specifications for this type of requirement, precise application studies are needed that provide information on the maximum permissible loads, speeds and, in this context, the setting of the optimum tyre pressure,” adds Christoph Frost, Director Commercial Products Bridgestone Central Europe. “In addition, a high level of resistance is required from the tyres when it comes to the daily transport of around 40 000 t of material. Converted, this results in a mass of around 670 t that a single tyre transports per day. Special attention is paid to a consistently good traction under changing road conditions and a high stability of the Bridgestone tyres, which contributes significantly to the safety during driving. Furthermore, they must be resistant to heat and cuts and have good self-cleaning properties.”
Bridgestone supports with product and service
Bridgestone is currently developing a new OTR tyre in order to ideally meet the special requirements of VA Erzberg GmbH in the future and at the same time to best withstand the weather and location-based challenges of the Alpine region: The Bridgestone 27.00 R49 Master Core is specially designed for use in hard rock open-cast mining and is characterised by its high durability and special resistance. But it is not only with products that Bridgestone supports VA Erzberg GmbH in its forward-looking venture. “The personal support, the comprehensive service offer as well as the technical competence and practical advice from Bridgestone are convincing. The cooperation is constructive, at eye level and always solution-oriented,” continues Dr. Peter Schimek.
This progressive partnership is based on the Bridgestone E8 Commitment, which represents the company’s vision to create social and customer value and contribute to a more sustainable society. The Bridgestone E8 Commitment – a framework of eight guiding concepts (Energy, Ecology, Efficiency, Extension, Economy, Emotion, Ease and Empowerment) – is designed to guide strategic priorities, decision-making processes, cultural development and sustainability activities across all business units.