In 2002 the resources were calculated at 512Mt but now total 328Mt, including 22Mt measured, 50Mt indicated and 256Mt inferred.

“While the revision has resulted in a 40 per cent reduction in total tonnage, it is significant to note that the JORC resource within the proposed mine areas remains unchanged at 150 million tonnes,” Macarthur chief executive and managing director Nicole Hollows said.

“The substantial majority of the tonnes that are no longer considered part of the JORC resource are in the higher strip ratio area north of the proposed mine area. Of the total 328 million tonne resource, 308 million tonnes is at depth of less than 100 metres.”

Macarthur said the Monto joint venture was continuing to evaluate opportunities to develop the project and was assessing options to convey the product coal to Gladstone, 140km away.

Noble has the lion’s share of the JV while Macarthur holds 41%, with the project covering Mining Lease 80101, EPC 613 and EPC 683.

Shares in Macarthur closed up 6c to $9.46 this morning.