Mine trucks versus road trucks and hoists: What hauling solution is best in underground mines?

There are two main scenarios when it comes to material hauling in underground mines. The first is the mine development phase, where the entire mine infrastructure is designed and constructed. This also includes any mine extensions, which are considered part of the development process. The second scenario is production, which begins once the mine is ready and ore extraction is underway. Both scenarios occur simultaneously in an underground mine, as operations continuously extract material from the ore body while also expanding and developing the necessary infrastructure to support ongoing production.

 

In both development and production, underground operations need an effective solution to transport ore and waste rock out of the mine. Several hauling methods are commonly used, including mine trucks, road trucks, and hoists. In this article, we will explore these different hauling options, how they work, their advantages and disadvantages, and the types of applications they are best suited for.

Mine trucks are specialized hauling vehicles specifically designed for transporting ore and rock material in the tight and rough underground environment. They come with various payload capacities and are built for different drift sizes. For example, Epiroc offers mine trucks ranging from 22 to 66 tonnes payload capacity, designed for different drift sizes, and available with conventional diesel engines, battery-electric power (including trolley systems), or diesel-electric drivetrains.

 

An alternative to mine trucks is conventional road trucks. These are less expensive, have less empty weight, and are commonly available, so why use a mine truck instead?

One of the main advantages of mine trucks is that they are specifically designed to withstand the harsh conditions of underground environments.

 

With thick steel reinforcements in all areas prone to wall contact, a mine truck typically only ends up with superficial scratches that do not affect functionality. In contrast, a road truck is likely to sustain more substantial damage from a similar wall collision. In the best-case scenario, only its plastic panels might be scratched, but more extensive damage is often expected.

 

All machines used underground must also be equipped with numerous safety features, such as built‑in fire suppression systems, ROPS/FOPS‑approved cabins, and additional failsafe braking systems. On Epiroc mine trucks, these features come as standard, or as common options, while they require costly special adaptations on road trucks.

Road trucks, even off‑road versions, require higher‑quality roads than those typically found in underground mines, especially if they are expected to maintain decent speeds and achieve a long service life. In contrast, mine trucks are built to handle far rougher conditions.

 

Potholes and rocks that would stop a road truck pose no issue for a mine truck. While driving through deep, muddy water is not ideal for any machine, mine trucks can tolerate significantly deeper water than road trucks.

While a road truck generally has a lower purchase cost, it is not designed specifically for underground haulage, which results in a shorter lifetime compared to a mine truck.

 

Reinforced frames and additional axles can extend a road truck’s lifetime to some degree, but these modifications also increase its overall cost. Additionally, tires on road trucks wear out much faster compared to the ones on a mine truck, leading to an overall higher tire cost for a road truck. Even if the purchase cost divided by the lifetime ends up being lower, the productivity of a road truck will still not reach the level of a mine truck of similar size.

 

Epiroc’s 65 tonne Minetruck MT65 S can operate for up to 16,000 hours before a midlife rebuild. After this service, the truck is restored to near new condition and continues to operate efficiently. In some cases, a Minetruck MT65 S has accumulated as many as 50,000 engine hours.

 

Another reason for the longer lifetime of a mine truck is that it is designed to operate at full engine power for extended periods. A road truck typically uses full power only for short bursts, such as during acceleration or when climbing inclines, and otherwise runs with the drivetrain under a fraction of its maximum load. In a mine, however, a truck may climb long inclines at full power for prolonged durations, sometimes for more than an hour. Road trucks can handle this, when necessary, but they are not built for it as a standard operating condition, which ultimately affects their lifetime.

Each underground mine is designed for a specific drift size. The chosen drift size depends on factors such as the shape of the ore body, production volume, and rock conditions.

 

Mine trucks are available in a wide range of sizes, from compact 2.4‑meter models to the largest 66‑tonne units with a width of 3.5 meters. This variety allows them to carry significantly higher load capacities compared to regular road trucks, which generally come in only one standard size.

 

The lower load capacity of a road truck increases the purchase cost per ton transported. Additionally, more trucks, and therefore more operators, are needed to achieve the same total hauling capacity, which further raises operating costs.

 

Moreover, the articulated design of mine trucks enables them to navigate much tighter curves than conventional road trucks, reducing the need for costly excavation work to widen underground passages.

Mine trucks can carry more load than road trucks within the same drift size due to their compact, purpose-built design. For a given production volume, this means fewer trucks are required when using mine trucks.

 

Traffic congestion is a common challenge in underground mines, and adding more trucks only increases that congestion. Beyond a certain point, introducing additional vehicles can reduce overall productivity.

 

Moreover, the articulated design of mine trucks enables them to navigate much tighter curves than conventional road trucks, reducing the need for costly excavation work to widen underground passages.

A key differentiator between mine trucks and conventional road trucks is the automation system. For mine trucks, the system is purpose‑built for underground use, where roads are narrow and winding and there is no GPS signal.

 

Autonomous underground driving with mine trucks is possible with systems such as Epiroc’s Deep Automation solution. Epiroc’s Deep Automation offers true 3D capability for underground operations, enabling orchestration of autonomous truck haulage across complex, multi‑level ramps. This breakthrough enhances fleet visualization and traffic coordination, paving the way for safer, more efficient operations at depths previously considered challenging.

 

By contrast, conventional road‑truck automation relies on GPS, which cannot be used underground because it requires a direct line‑of‑sight to multiple satellites and lacks environmental awareness. Such systems struggle to handle the tight curves and the highly dynamic environment typical of underground mining operations.

An alternative to using trucks, whether road trucks or mine trucks, is hoisting. Hoist systems are highly productive, have low operating costs, and require minimal maintenance. They are also naturally electrified, which means they generate no exhaust within the mine.

 

A hoist system can transport ore directly to the surface. However, hoisting does not completely replace truck usage. Trucks are still required to move the ore to the hoist loading point and, in some cases, from the hoist discharge point on the surface to a dumping or processing area.

 

Hoisting offers efficient transport between two fixed points, whereas trucks provide a flexible system capable of moving material between various locations both underground and on the surface.

While trucks have lower initial investment costs and can adapt to the mine’s evolving infrastructure, a hoisting system requires more extensive planning and a significantly higher upfront investment.

 

Determining the position and depth of a hoist demands consideration of what the mine will look like more than a decade into the future. One important factor is that hoisting becomes increasingly advantageous as mines reach greater depths.

 

Once a hoist is installed, its location is fixed, whereas the mine continues to expand and change over time.

Hoists are generally very reliable hauling systems, but occasional failures can still occur, causing production to stop. They also require stops for regular maintenance.

 

If no ramp is available as an alternative route to bring people to the surface, a hoist shutdown can also pose a safety risk. In contrast, if a truck is taken out of operation for service, it results in only a minor production loss, as the remaining trucks in the fleet can continue operating normally.

If a mine has excellent road conditions, ample clearance to the walls, and no issues with traffic congestion, road trucks may be the best option. However, underground mines where these conditions are not met, choosing mine trucks as the hauling solution delivers higher productivity and a lower total cost.

During development, road conditions near the face are often poor. Road trucks may struggle to cope with these conditions, whereas mine trucks handle them without difficulty.

Ventilation is always a challenge during mine development.

 

Fortunately, both mine trucks and road trucks are available in battery‑powered versions, providing zero tailpipe emissions.

 

Hoists are normally not an option during mine development. 

During mine production, conditions are generally more stable. Ventilation and road maintenance are easier to manage, although the higher traffic density causes roads to deteriorate quickly, making it challenging to maintain them at an acceptable standard. What is considered “acceptable” differs, of course, between road trucks and mine trucks.

 

The chosen mine production method also plays a significant role. Narrow vein mining is almost continuous mine development, while large‑scale stoping and block caving operate more like full underground industries.

 

When production remains concentrated in one location for a long period, it may be justifiable to invest in concrete roads suitable for road trucks, or, in extreme cases, even rail systems.

We have talked in detail about each hauling method and when it is best to use it. Below is a summary of each hauling method.

Mine trucks are the most reliable all-round choice for most underground hauling situations.

 

• Road conditions are rough, especially during mine development or in areas close to the face.
• Drift sizes vary and tight curves or limited space require highly maneuverable, articulated vehicles.
• High productivity is needed with fewer trucks and less traffic congestion.
• Durability is important, e.g., extended full‑power uphill hauling and constant wall contact.
• Ventilation is limited and battery-electric mine trucks can be used.
• Roads deteriorate quickly (typically in production with high traffic).
• Longer machine lifetime is a priority.
• Autonomous mine trucks are required underground.

 

You can explore the whole range of mine trucks offered by Epiroc here.

Road trucks can be cost-effective, but only in mines with good roads, generous space, and low traffic intensity.

 

• Road conditions are excellent, and wide enough to avoid damage.
• There is ample clearance with fewer risks of wall impacts.
• Traffic congestion is not an issue (i.e., low fleet size).
• A lower purchase cost is important, and standard road trucks can meet productivity needs.
• Infrastructure allows for high-quality roads, sometimes even concrete ones.
• Production is localized long-term, making it worth investing in improved roads or even rail.

Hoists excel in deep, long-life mines where high-volume vertical transport is needed.

 

• The mine is very deep.
• High, continuous productivity is required between two fixed points.
• Low operating cost and low maintenance are long-term priorities.
• A stable, predictable, long mine life justifies the large upfront investment.
• Zero exhaust emissions underground are needed (hoists are naturally electric).