Trailing cables are the lifeline of electrically powered underground mining equipment. Continuous miners, shuttle cars, longwall shearers, and load-haul-dump vehicles all rely on trailing cables to deliver the power they need deep underground — where diesel is restricted, and electrical power is the only viable option for high-output machines.

The problem is that trailing cables operate in one of the most punishing environments imaginable: narrow mine roadways, in constant contact with the mine floor, subjected to continuous movement, crushing loads from passing equipment, and exposure to moisture, heat, and ground water. Without proper cable management, a trailing cable degrades rapidly — and in underground mining, rapid cable degradation has direct consequences for productivity, safety, and operating cost.

This guide explains how trailing cable handlers work, what they actually do to extend cable life and protect mine workers, and what to consider when specifying a trailing cable management system for an Australian underground mining operation.

Key Takeaways

• Trailing cables connect mobile underground mining equipment to fixed power sources — and must move with the machine throughout its operating cycle
• Unmanaged trailing cables are a primary cause of cable damage, electrical faults, and serious safety incidents in underground mines
• Trailing cable handlers automate the pay-out and retrieval of cable to keep it off the mine floor and out of machine traffic paths
• The right handler specification depends on cable weight, machine travel distance, mining method, and roadway geometry
• Australian mine operators including Fortescue, BHP, and Glencore use purpose-built trailing cable handling systems to meet their safety and production requirements

What Is a Trailing Cable — and Why Does It Need Managing?

A trailing cable is a flexible, heavy-duty electrical cable that connects a mobile underground mining machine — typically a continuous miner, shuttle car, or electric LHD — to a fixed power distribution point in the mine roadway. As the machine moves forward during its operating cycle, it pays out cable behind it. When it returns or repositions, the cable must be retrieved and stored without kinking, crushing, or excessive coiling that could damage the insulation.

A single trailing cable for a continuous miner can weigh over 10 kg per metre and run to 150 metres in length — that’s well over a tonne of cable that needs to move with the machine across every operating cycle. Left unmanaged, this cable lies on the mine floor, where it’s exposed to:

• Crushing from shuttle cars and other mobile equipment driving over it
• Abrasion damage as it drags across the mine floor during machine movement
• Flooding and ground water ingress at any point where the outer sheath is breached
• Mechanical stress at the point where cable connects to the machine, particularly under tension during rapid movement
• Heat build-up from coiling or bunching in poorly ventilated sections of roadway

Each of these failure modes creates an electrical fault risk. In a coal mine, an electrical fault in the presence of methane is a catastrophic event. In a hard rock mine, the consequences are less explosive but no less serious from a production and safety standpoint — an earth fault in an underground power system can cause immediate power loss to an entire section of the mine.

How a Trailing Cable Handler Works

A trailing cable handler — also called a cable reel system or cable management unit — automates the pay-out and retrieval of a trailing cable as the mining machine moves through its operating cycle. The core principle is simple: keep the cable off the mine floor, under controlled tension, and stored safely when not deployed.

Types of Trailing Cable Handlers Used in Australian Mines

Not all underground mining operations use the same trailing cable management approach. The mining method, machine type, and roadway geometry all influence which system is appropriate.

Fixed-Position Cable Reels

Fixed cable reels are mounted at a fixed point in the mine roadway — typically at the last power distribution point before the working section. The machine travels away from the reel, paying out cable, and returns to retrieve it. These systems are most common for shuttle cars in room-and-pillar coal mines, where the machine operates on a defined back-and-forth cycle within a limited panel area.

Machine-Mounted Cable Handlers

For continuous miners and larger machines that advance progressively through a panel, the cable handler is often mounted on the machine itself or on a dedicated cable handler unit that follows the machine. This approach keeps the cable management system close to the point of use and reduces the total cable length required.

Towed Cable Trailers

In some applications — particularly for electric LHD vehicles in hard rock mines that operate across longer distances and more varied routes — a towed cable trailer follows the machine, paying out and retrieving cable as the vehicle moves. Redmond Gary’s trailing cable trailers are designed for exactly this application, engineered to handle the weight and movement demands of Australian hard rock mining environments.

What to Specify When Selecting a Trailing Cable Handler

Getting the specification right requires working through several variables before you talk to a supplier. The most important are:

• Cable weight per metre and total cable length — these determine drum capacity, motor sizing, and the structural requirements of the handler frame
• Machine travel distance — the maximum distance the machine travels from the fixed power point must be within the handler’s full drum capacity with a safety margin
• Machine travel speed — retrieval speed must match or exceed the machine’s maximum reverse speed to prevent cable slack
• Roadway height and width constraints — underground clearance is tight; the handler’s overall dimensions must fit within the mine’s roadway profile
• Drive system preference — hydraulic drive systems are common where existing hydraulic circuits are available; electric drive is preferred where clean power and precise speed control is a priority
• Slip ring voltage and current rating — must match the machine’s supply voltage and maximum load current, with margin for starting currents

Australian Case Study

EV Self Loading Cable Trailer – Fortescue, Pilbara WA

Redmond Gary recently delivered a specialised 3.5 tonne EV cable trailer to Fortescue’s Pilbara operations – part of the broader electrification of the mines Mobile fleet. This trailer is designed to manage cable when installing and removing pumps From dewatering bores. The trailer feathers cable drum with drive system, crane with boom at The back of the trailer and winch to lower and retrieve the pump and cable. The project demonstrates how Australian-made, Purpose-built cable systems can directly support the mining industry’s electrification transition – rather than Adapting equipment designed for a different era.

Maintenance: The Factor That Determines Long-Term Performance

A trailing cable handler operates in one of the harshest mechanical environments in industry. Dust, moisture, vibration, and continuous cycling put enormous demands on the drive system, drum bearings, level winder, and slip ring assembly. A well-specified handler that isn’t maintained to its service schedule will fail prematurely — and in an underground mine, an unplanned handler failure at the wrong moment has immediate production consequences.

Critical maintenance items for trailing cable handlers include:

• Slip ring inspection and cleaning — the most common source of electrical faults in cable handler systems; recommended at every scheduled maintenance interval
• Level winder alignment check — misalignment causes uneven cable stacking, which progressively damages the cable through pressure points on the drum
• Drive motor and gearbox fluid levels — hydraulic and gear oil condition directly affects drive performance and component life
• Drum bearing inspection — bearing failure in a loaded drum creates a safety-critical situation; early detection through vibration monitoring is best practice
• Cable connection and termination inspection — the point where the trailing cable connects to the slip ring assembly is a high-stress location; inspect for signs of insulation damage or conductor fatigue at every opportunity

Frequently Asked Questions

What is the difference between a trailing cable and a trailing cable handler?

A trailing cable is the flexible electrical cable itself — the conductor, insulation, and protective sheath that delivers power from a fixed distribution point to a mobile mining machine. A trailing cable handler (or cable reel system) is the mechanical device that stores, pays out, and retrieves the cable during machine operation. The cable is consumable and will be replaced multiple times over the life of the handler. The handler is the capital equipment investment; the cable is the ongoing operational cost.

How long does a trailing cable typically last in an underground mine?

Trailing cable life varies significantly depending on the mining method, operating conditions, and how well the cable is managed. In a well-managed operation with a properly specified cable handler, a trailing cable might last 12–18 months before requiring replacement. In poorly managed operations — where the cable is regularly run over, dragged across rough ground, or stored incorrectly — cable life can be as short as a few weeks. The cost of a replacement trailing cable for a continuous miner is substantial; the cost of a cable-related electrical fault or injury is far greater. Proper cable management is consistently one of the highest-return maintenance investments in underground mining.

Do electric mining vehicles (EVs) use trailing cables?

Some do, some don’t. Battery-electric mining vehicles that are self-contained don’t use trailing cables during operation — they run on their onboard battery and return to a charging station when depleted. However, some electric mining machine designs use a trailing cable for continuous power supply during operation, particularly for high-power machines where the battery weight and size required for full-shift operation would be impractical. Trolley-assist systems on haul trucks in open-cut mines use a different form of trailing conductor connection. The Fortescue EV cable trailer project Redmond Gary completed is an example of bespoke trailing cable management for a new generation of electric mining machines.

What Australian standards apply to trailing cable handling equipment in mines?

Trailing cable handling equipment in Australian underground mines is subject to the relevant state mining regulations (administered by resources regulators in each state), AS/NZS 4871 (electrical equipment for mines and quarries), and the general WHS plant requirements that apply to driven equipment. In Queensland coal mines, the Coal Mining Safety and Health Act and associated regulations set specific requirements for electrical equipment in underground environments. The exact compliance requirements depend on the mine type (coal vs metalliferous), state, and the specific classification of the underground environment (potentially explosive atmosphere vs non-explosive).