245 Seven diesel-electric Liebherr T236 trucks equipped with current collectors operate on trolley. Additional six diesel-mechanic Komatsu HD785-7 and two diesel-mechanic Komatsu HD785-8 trucks cover mainly horizontal and downhill ore transport. The T236 trucks are equipped with current collectors which carry contact shoes on their end where contact sliders are inserted. Spring forced collector bars establish the necessary pressure against the contact wires. With this trolley bus like installation the trucks can handle 0.6 m vertical and 3.5 m lateral distance deviations from the centre of the contact wires. The operating voltage level for the T236 trucks is between 750 V and 1050 V DC, the inverter for the AC traction motors limits the current at 1400 A. The maximum current capacity of the current collector is 1880 A. Up to 150 kW power is drawn to supply the alternator to operate in motor mode for powering the central gear for the hydraulic pumps and for pushing the diesel engine to 1600 rpm to have almost no diesel consumption. The trolley haulage performance with an average payload of 102 t on an average grade of 7.4 % is summarized in the following table. For the given figures site-specific conditions of VA Erzberg’s mining operation must be mentioned. Winter season can last from November to April, with intermediate heavy snowfall and temperature changes below and above zero degree Celsius during the day. Snow chains on rear tires are put on for half of the winter season. During summer season, there are occasional heavy rainfall periods. Although there is increased effort in road construction and maintenance, the overall road condition varies between good and poor. Table 1 - Trolley performance data from 01-01-2025 to 12-31-2025 Tonnage hauled alongside trolley 4.68 Mio t Haulage distance on trolley 137047 km Avg speed on trolley 20.2 km/h Cumulative height hauled 7553 km Avg grade 7.4 % Specific energy consumption per km (average payload 102 t) 51.4 kWh/km Number of de-railing incidences per 1000 km 7 No/1000 km 3. COST SAVING POTENTIAL The specific electrical energy consumption is the value in focus to calculate the energy saving. Average diesel consumption for diesel powered trucks on uphill haulage ramps is 165 litre per hour at an average speed of 15 km/h. This results in a fuel consumption of 11 litre per km which gives a specific energy equivalent of 130 kWh per km. For trolly haulage consuming
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