Exposed live conductors underground

Mine type

All underground mines

Incident

Fortunately no injuries occurred when underground mine employees were exposed to non-insulated energised power conductors in an underground mine.

A pulsating fire resistant anti static (FRAS) pump discharge line wore through the mining cable insulation and sheath to expose bare copper conductors.

Equipment

Type 275 mining trailing cable, dewatering pump and 1000V electrical power supply

Hazard

Should anyone have touched the exposed conductor they would have received an electric shock which could have proved fatal.

Cause

A type 275 mining cable utilising conductive rubber screening (eg shuttle car cable) was being used to power a dewatering pump in an underground coal mine. The short circuit, earth leakage and earth continuity circuit protection did not recognise the hazard as there was no circuit to earth due to both cable and hose being non-conductive. Protection settings for pump stations and like installations do not offer personal protection from electric shock. Lack of potential hazard awareness during installation of the pump station and inadequate subsequent inspection activities.

Comments and recommendations

The site recognised Standard for Cable Management is to be reviewed to ensure known and identified hazards such as wear and abrasion are managed in an appropriate manner.

Cables must be protected against physical damage and an appropriate management/ inspection system must be introduced to monitor cable condition.

Authorised by Brian Lyne - Deputy Chief Inspector of Mines (Coal)

Contact: minesafetyandhealth@dnrm.qld.gov.au

Issued by Queensland Department of Natural Resources and Mines