The mine has rated the relevant June 2 initiated blast fume as a category 2 – which means it did not need to report the fume to the EPA under mining regulations.

Video footage of the carefully planned blast was also taken and shared with the EPA to support this case.

While ICN is aware of at least one contrasting view that the EPA will drop the investigation, this was not confirmed by the agency.

“The EPA is still investigating this matter, and will review the mines video footage and the incident report as part of this investigation,” a spokeswoman told ICN.

The EPA was first notified about the blast fume from local landholders.

“At this point, the EPA has no evidence there was any environmental harm, however this will be part of the investigation,” EPA north branch director Gary Davey said on Monday.

In April the mine was considered 93% built. In the March quarter Maules Creek produced 1.12 million tonnes run of mine with saleable output of 0.99Mt.

The mine’s finished first stage capacity will be 6.5 million tonnes per annum ROM while a bolstered fleet from around December is expected to expand capacity to 8.5Mtpa ROM by early next year.