Deputy director-general Richard Pearson said the mine’s expansion underwent a rigorous examination before approval for the $70 million expansion of the Metropolitan longwall mine which will increase by 1 million tons per annum of hard coking coal production capacity by 2014. It is located 1.5 kilometres from the reservoir.

“The merits of the proposed expansion of the Metropolitan mine were closely examined by the Department of Planning and the Planning Assessment Commission (PAC), which included specially appointed independent experts, before approval was given in 2009,” he said.

“Both the department and the PAC found the risk of the mine causing water loss from the dam was ‘very low’. Nevertheless, strict conditions were imposed on the company to ensure any water loss from the dam or its catchment due to mining would be ‘negligible’.”

The approval included a barrier to protect the Waratah Rivulet, meaning 8.6 million tonnes of coal with an estimated market value of $1-2 billion will not be mined.

To date, the mine’s monitoring program has shown absolutely no indication of water loss due to mining, either from the streams above the mine or from the reservoir downstream, Pearson said.