Haul trucks can break down several times a year, often requiring another truck to be diverted from production to provide hydraulic support for steering, braking, and tipping.
This increases cost-per-tonne and introduces safety risks, especially when hydraulic pressure is unstable or systems are leaking or contaminated. To eliminate these hazards and avoid relying on another truck’s hydraulics, the client engaged Hydraulic Distributors to engineer a safe, self-contained recovery solution for their EH4500 fleet.
Scope of Work
Hydraulic Distributors was engaged to design, engineer, and manufacture a custom hydraulic power unit (HPU) capable of:
- Providing full hydraulic pressure to operate the disabled truck’s steering, braking, and park-brake release circuits.
- Tipping the fully loaded dump tray without relying on the recovery truck’s hydraulic system.
- Enabling controlled, compliant towing of the disabled truck back to the maintenance facility.
- Functioning as a standalone power source, independent of the truck’s own engine or electrical systems.
- Integrating all Australian mining safety, compliance, and OEM recovery requirements.
The goal was to create a rugged, field-ready solution that eliminated operational delays while significantly improving safety during breakdown recovery.
Challenges
1. Safe and Secure HPU Mounting
The HPU needed to be mounted on the truck in a way that:
- Withstood extreme vibration, corrugations, and high-G shock loads on haul roads.
- Maintained stability during towing and tipping.
- Met MDG 15 requirements for mobile and transportable plant.
- A custom mounting frame and tie-down system were engineered to handle heavy dynamic loads.
2. Integration Into an Existing Hydraulic System
Connecting an external power pack to the truck’s OEM hydraulic architecture required:
- Understanding the truck’s steering, brake, and hoist circuit pressures.
- Identifying OEM-approved connection points.
- Ensuring compatibility with check valves, accumulators, and flow limits.
This was completed in alignment with MDG 41 – Fluid Power Safety and the OEM’s recovery manual.
3. Designing a Protective, Breathable Enclosure
The unit required a robust cage that:
- Protected the HPU from rock strikes, debris, and vibration.
- Provided breathability for the hydraulic reservoir through filtered/desiccant breathers.
- Allowed adequate cooling airflow.
- Enabled safe access to gauges, valves, and E-stop controls.
The final design included a reinforced safety enclosure with built-in filtration and high-flow ventilation panels.
4. Preventing Incorrect Hose Connections
To eliminate the risk of misconnection in a high-pressure, high-risk environment:
- Quick-release couplings were provided with fail-proof male/female arrangements that physically prevented plugging into the wrong circuit.
- Hoses were colour-coded, tagged, and supplied with whip-checks and abrasion-resistant covers.
- All hoses met or exceeded Australian mining pressure ratings.
This ensured full compliance with MDG 41 hose and fitting requirements.
5. Standalone Power – No Cab Interaction
The mine required all power pack functions to be completely independent of the truck’s cabin controls. We engineered:
- A dedicated diesel power system.
- Independent hydraulic controls located on the HPU skid.
- Operator access protected by a safety zone.
This removed reliance on failed truck electronics and ensured simple operation.
6. Full Integration of Australian Mining Safety Procedures
The power unit was engineered in compliance with:
- Isolation & Lockout/Tagout (LOTO)
- Zero-energy verification
- OEM-approved recovery procedures
- MDG 15, MDG 35, MDG 41
- AS/NZS 4024 (Safety of Machinery)
- AS 5062 (Fire Protection for Mobile Equipment)
- High-pressure hydraulic safety guidelines
- Site-specific towing and recovery rules
The unit supplied safe, controlled hydraulic pressure to steering and braking circuits while preventing over-pressurisation, contamination, or unintended truck movement.
7. Built-In Protection & Automatic Shutdown Systems
For operational reliability and simplified maintenance, the HPU included:
- Hose burst protection valves
- Low-pressure automatic shutdown
- Emergency Stop (E-Stop)
- Thermal burn protection
- Overheat protection with temperature, pressure, and low-oil switches
- Integrated monitoring panel with visual indicators
- Fire-resistant hoses and covers
- Filtered, breathable tank system to prevent vacuum/pressure damage and contamination ingress
All safety systems were integrated into the protective cage to keep the unit compact, low-maintenance, and mine-ready.
8. Designing the HPU Around Operational Requirements
In addition to engineering constraints, the power unit needed to be built around real-world operational use in the mining environment:
- Needed to be designed around the application, customer recovery requirements, and the truck’s pressure/flow demands, ensuring reliable control of steering, braking, and hoist functions.
- Mountable anytime, anywhere, with a mobile configuration allowing the power pack to be transported directly to the disabled truck without specialist equipment.
- Included a diesel engine with a 20L fuel tank, providing more than 4 hours of continuous operation, allowing a full recovery cycle on a single tank.
These requirements ensured the HPU was not only technically compatible but also practical, field-deployable, and robust enough for continuous mining operations.
For innovative hydraulic solutions from a team with over 100 years’ combined hydraulic experience, contact our team today on 02 8608 2144.
