Comparative Analysis of Haulage Technologies for the Lili Pit Extension at the Rabenwald Mine

Imerys Talc Austria GmbH operates the Rabenwald Mine, the largest talc-producing open-pit in Central Europe. The company plans an extension downhill, requiring the transport of around 1.6 million t of waste rock each year from 2033 until 2048. Continuing to use diesel-powered trucks involves high costs and greenhouse gas (GHG) emissions, primarily due to high tonnages and significant altitude differences. To explore more sustainable options, a literature review examined advancements in alternative haulage methods, including alternative fuels, electrification, and in-pit crushing and conveying (IPCC) as well as the challenges of continued diesel use. Subsequently, key company criteria were identified, and various haulage scenarios were modeled to estimate energy demand, GHG emissions, and financial feasibility under derived energy price and carbon intensity projections.
The findings indicate that the diesel-powered Base scenario has the lowest Net Present Cost (NPC), even with a 30% increase in diesel prices. However, it results in higher long-term energy expenses and GHG emissions, particularly in the later stages of the extension due to increasing carbon taxation. All alternative scenarios require significant upfront investments, ranging from 2.2 to 2.8 times that of the Base scenario in the first year of the project. Battery electric trucks with swapping technology can reduce operating energy costs by more than 50% compared to diesel and lower Scope 1 and 2 emissions by up to 89%, with only slightly higher NPC. At the same time, they demonstrate approximately 7% higher productivity during operation. A trolley assist setup could significantly reduce the required battery capacity and when combined with diesel-electric trucks, it could lower energy costs by 29% while reducing GHG emissions by 51%. However, implementing a trolley assist system requires not only high initial capital investment but also extensive long-term planning. Hydrogen as fuel for an internal combustion engine also offers low emissions when produced by renewable energy, but its feasibility depends on a well-developed hydrogen supply chain and substantial infrastructure investment. Meanwhile, IPCC provides limited benefits, as its high energy consumption for waste rock crushing offsets its efficiency advantage.
Overall, diesel-powered trucks remain the most economical choice in the mid-term, while battery electric haulage appears to be the most promising long-term solution for reducing emissions economically, provided that battery capacity is carefully planned, and adequate power infrastructure is established at the mine site.