The Queensland Mines Inspectorate has raised concerns that standards in the installation, maintenance and use of electrical equipment at Queensland underground coal mines have slipped.

It blamed the increase in incidents on the resources boom and the ensuing increase in employee numbers.

In its safety bulletin it listed a number of incidents that have occurred this year, including:

Non-certified equipment installed in an intrinsically safe circuit;

Flameproof alternator found with the cover plate missing on two occasions:

Flameproof enclosure found with an open gland entry;

Flameproof enclosure compromised due to the “O” ring incorrectly fitted;

Damaged flamepath remained unnoticed for several shifts – despite checks occurring;

Incorrect trip settings applied to methane monitor on the continuous miner;

Incorrect installation or parameters set on gas monitors, with failsafe operation disabled on three occasions;

Methane monitor made inoperable due to cover over sensor;

Flameproof lights on underground vehicles damaged on seven occasions;

IP55 equipment installed in an Explosion Risk Zone 1 location on three occasions;

Incorrect wiring of the cable pilot circuit;

Conveyor pull-switch disabled due to incorrect internal wiring; and

Incorrect isolation used to gain access to electrical enclosures.

The inspectorate said the causal factors in all the above incidents ranged from poor electrical standards maintained by electrical tradespersons to poor operational standards.

“Whilst all events are of concern, the number of incidents that resulted in compromised explosion protection techniques is a particular concern,” the inspectorate said.

“The personnel involved range from newcomers to the very experienced, including both full-time and contracted employees.”

It recommended that expected work standards and practices be clearly detailed and understood by all workers and that management ensure systems are in place to adequately supervise and audit the quality of work being carried out by workers onsite.