Electric underground loaders

An electric underground loader draws its power from a battery instead of a diesel engine, which allows the energy to be used more efficiently with fewer losses. The battery powers the electric motors, making it possible to separate the traction motors from the auxiliary hydraulic motors. This removes the need to compromise between traction and essential hydraulic functions such as steering, braking, and operating the boom and bucket. The result is a machine that is more agile, has better responsiveness, and can therefore work more productively.

Even though the efficiency of the battery is higher than diesel, its running time is usually lower. This means that a battery-electric machine needs to charge more frequently than a diesel loader needs refuelling. To manage this, charging the electric loader must be planned, and whenever possible, onboard opportunity charging can be used during idle periods or natural shift breaks.

There are theoretical estimates for how long a machine can operate on a single battery charge, but in practice the running time depends heavily on factors such as size of battery, weight of the machine, the type of operation, road conditions, whether the load cycle involves ramp driving, the operator’s skill level, and more.

Below are the calculated estimates:

Mine development, 15% ramp, 250 m cycle

Scooptram ST10 G - 3,13 hours

Scooptram ST14 SG - 3,15 hours

Scooptram ST18 SG - 3,9 hours

Production, 0% ramp, 250 m cycle

Scooptram ST10 G - 3,95 hours

Scooptram ST14 SG - 4,4 hours

Scooptram ST18 SG - 4,9 hours

There is no standardized load cycle to refer to. However, Epiroc uses computer models based on a predefined load cycle, which are then compared with live tests to verify and ensure that the product meets its performance targets.

Charging time depends on the type of charger available and the battery’s state of charge when charging begins. A full charge, from 10% to 90% state of charge, typically takes around one hour. However, it’s often beneficial to use opportunity charging, taking shorter charging sessions whenever suitable.

Epiroc underground loaders can use both onboard and off‑board charging. They are equipped with a standardized CCS (Combined Charging System) interface, the same system commonly used in most on‑road battery-electric vehicles.

Electric motors require almost no maintenance over their lifetime. By removing the diesel engine, which needs frequent maintenance such as filter and oil changes, as well as regular inspection of belts and other components, a significant cost is eliminated.

An electric underground loader significantly improves the local environment in the mine. The machine produces no diesel-related emissions such as CO₂, NOx, or particulate matter. It also generates less heat, emits far less noise, and creates lower vibration levels. Altogether, these factors contribute to a better working environment for operators and anyone else working in the mine.