The study was undertaken by independent consultants, Mining Plus Pty Limited, and was based around the 2009 JORC resource estimate produced for Bezant by Snowden.
This showed Mankayan to contain an indicated resource of 1.1mln tonnes of copper and 3.7mln ounces of gold, with additional inferred resources of 200,000 tonnes of copper and 600,000 ounces of gold.
According to the new study, Mankayan supports several scenarios for potential future development, including a smaller scale lower cost sub-level caving operation, and two larger block caving options.
Both block caving options would support an average production grade in excess of 0.64% copper equivalent.
The study estimated that the project has a five year lead time to production under a variety of development scenarios.
The two preferred block caving methods give respective net present values for the project of US$1.18bn and US$797mln, with the trade-offs including greater capex for the higher value project.
"Mankayan is a major, well-delineated copper-gold porphyry style deposit and this latest Mining Plus study serves to demonstrate potential robust development options able to sustain an average mining grade above 0.64% copper equivalent at average costs below US$20 per tonne,” said chief executive Laurence Read.
"Historic studies on the project were designed to optimise the mining model without necessarily taking account of extremely influential factors such as capital spread, the high-grade core, mining rates and footprint, and possible intermediary routes in order to achieve initial production from a significantly reduced capital outlay. This latest study has therefore been most informative and enables Bezant's management team to plan for different potential production scenarios ranging from six million tonnes per annum to 12 million tonnes without unduly affecting financial ratios.”