Installation of Small Cable Trays in Underground Mines

Proper installation of small cable trays in underground mines requires careful material selection, secure support systems, correct spacing, grounding, and adherence to safety standards to ensure reliable operation and personnel safety.Material Selection

For underground mines, cable trays must resist corrosion, mechanical stress, and environmental hazards. Common materials include galvanized steel, stainless steel (AISI 316L), aluminum, and GRP (glass-reinforced polyester), each offering varying corrosion resistance and strength characteristics. GRP trays are lightweight, corrosion-resistant, and suitable for damp or chemically aggressive environments, while stainless steel provides high durability and resistance to pitting and stress corrosion ( ).

Support and Mounting

Cable trays should be supported at regular intervals to handle the weight of cables and any future additions. A minimum of 18 meters of electrical continuity is recommended, and supports must meet the load requirements of the tray system ( ). In underground mines, supports can be attached to walls, ceilings, or structural beams, ensuring that the tray remains level and accessible for maintenance. Use laser or string lines to establish proper elevation and alignment before installation ( ).

Spacing and Layout

Maintain a minimum clearance of 300 mm above or between installed systems to allow for cable installation and maintenance ( ). For small instrumentation or control cables, rung spacing of 150–230 mm is recommended to prevent sagging and maintain cable organization ( ). Avoid sharp bends and respect the minimum bend radius of cables to prevent damage.

Grounding and Electrical Continuity

Ensure that the cable tray system is properly grounded to prevent electrical hazards. Electrical continuity should be verified at intervals, and bonding connections must comply with mining electrical safety standards ( ).

Handling and Safety

• Unloading and storage: Store trays off the ground in a dry, ventilated area to prevent corrosion or mechanical damage ( ).
• Personal safety: Workers should wear gloves, steel-toed footwear, and helmets. Do not use cable trays as walkways or ladders ( ).
• Inspection: Inspect all materials for damage or corrosion before installation. Non-conforming materials should be returned to the supplier ( ).

Installation Procedure

1. Material inspection: Verify all trays, supports, and accessories against approved specifications ( ).
2. Layout planning: Determine tray routes, elevations, and support points.
3. Support installation: Secure brackets, hangers, or frames to structural members.
4. Tray placement: Position trays on supports, ensuring level alignment and proper spacing.
5. Cable installation: Lay cables according to type and size, maintaining bend radius and separation for power and control lines.
6. Covering and protection: Use solid or ventilated covers where required to protect cables from dust, water, or mechanical damage ( ).
7. Final inspection: Verify alignment, grounding, and load capacity before energizing the system.

Maintenance Considerations

Regular inspections are essential to check for corrosion, mechanical damage, or loose connections. Ensure that any additional cables added in the future do not exceed the tray's load capacity ( ). By following these guidelines, small cable trays in underground mines can be installed safely, efficiently, and in compliance with technical and regulatory requirements, ensuring long-term reliability of electrical and control systems.