The blast was measured at 126.1 decibels at one monitor, exceeding the 120 decibel limit and resulting in one complaint.

“After a review of the incident in line with the department’s compliance policy, and given a recent history of blasts exceeding the overpressure limit at Integra, the department issued the penalty notice,” the department of planning said in its July compliance report.

In response to the department’s actions, Integra Coal has committed to measures to minimise the risk of further breaches of blast overpressure limits.

This will include ensuring all exploratory or test holes are filled and closed off immediately after completion and conducting comprehensive checks in the field and review records to check for old drill holes prior to commencing the drill program for the blast.

It has also committed to change sign-off procedures following loading of the explosive and has undertaken to improve processes to ensure better drill rig accuracy and improve notification to neighbours about blast times.

Integra was in the NSW government’s bad books in July 2011, when the newly appointed minister for resources Chris Hartcher ordered that the mine be shut after excessive levels of methane were discovered.

In March, the NSW Department of Planning and Infrastructure cleared Vale’s proposed extension of Integra despite earlier problems in the past with safety at the underground mine.

The director-general allowed Vale to modify its project approvals to extend the north open cut out-of-pit dump to the east and south and increase the maximum height of the north open cut emplacements from 135m to 141m.

The department’s assessment found the proposed modification would lead to minor additional dust impacts for residences, with levels remaining below relevant criteria and resulting in a slight increase in noise levels which were unlikely to lead to perceivable differences.

The open cut coal mining operations are located south of Integra underground and comprise the north open cut and south open cut, including the recently approved western extension.

The open cut operations produce both semi-hard and semi-soft coking coal (70%) and thermal coal (30%) for export.

The underground operation produces high quality, semi-hard coking coal for export, with the current approved production level set at a maximum of 4.5 million tonnes per annum of ROM coal.

Current approved maximum production levels are 1.5Mtpa of ROM coal from the north open cut and 4.5Mtpa of ROM coal from the south open cut.