Cable reel system design for underground mining.

Project overview

ASTCAD designed a fully motorised cable reel system for a NSW-based underground coal mining contractor. The reel handles 800m of high-voltage trailing cable for a continuous miner, with automatic level-wind, slack-cable detection and overload protection. The design complies with AS/NZS 4871 for electrical equipment in coal mines and AS 4024 for safety of machinery.

The challenge

The existing manual reels were causing cable damage at the slip-ring assembly and required two operators to manage during retreat mining. The client needed a self-managing reel with automated speed control synced to the miner’s tramming speed, plus intrinsically safe sensors for methane-rated environments.

Our approach

• Hydraulic motor sizing for 18 kN constant pull with cable on full and empty reel
• Level-wind mechanism with optical cable position feedback
• Slip-ring assembly redesign with replaceable carbon brushes accessible without dismantling
• FEA validation of drum shaft and side flanges for fatigue at 50 reversals per shift
• Ex-rated enclosure design for control panel to AS/NZS 60079

Deliverables

• Full mechanical assembly drawings (162 sheets)
• Hydraulic schematic and component schedule
• Electrical schematic and control logic narrative
• Manufacturing dossier including FEA reports
• Operator manual and maintenance schedule

Outcome

Three units were built and deployed to a Hunter Valley coal mine. Cable damage incidents dropped to zero in the first 12 months. The single-operator design freed up one crew member per shift, with measurable productivity gains during retreat-mining cycles. The client commissioned a second batch of five reels in 2024.

How we approach cable reel system design

Cable reel system design for underground mining balances three unforgiving constraints: the cable’s minimum bend radius, the machine’s duty cycle, and the operating envelope underground. We size drums and sheaves from the cable manufacturer’s data rather than habit, design tensioning systems that protect the cable across the full payout range, and select drives and slip rings rated for the electrical load and the environment. Structural design of the reel frame is verified for the dynamic loads of payout and retrieval, and every rotating element is guarded to the machinery safety standards the mine’s auditors will actually check.

Deliverables for mining equipment projects

A complete package includes general arrangement drawings, fabrication drawings for the drum and frame, mechanical schedules for drives and bearings, electrical interface documentation for the slip ring and controls, and a design verification summary covering structural and mechanical calculations. We document maintenance access and cable replacement procedures at design stage, because a reel that requires a workshop visit to re-cable costs the mine more in downtime than the reel cost to build.

If you are specifying or replacing cable management on mobile plant, we can review the machine duty and cable specification and quote the reel system design as a defined scope. Designs are delivered fabrication-ready, and we support the build through fabrication queries and factory testing.

Reel systems are also where mechanical and electrical scope most often falls between two contractors, so our documentation states the interface explicitly: who supplies the slip ring, who terminates the cable, what the control system expects from the tension feedback. Projects that define this on the drawings avoid the commissioning-week argument that projects without it reliably have. We have documented reel systems for longwall equipment, shuttle cars and surface mobile plant, and the interface lessons transfer across all of them.