A Preliminary Economic Assessment (PEA) on the Kora gold deposit at K92 Mining’s Kainantu Gold Project in Papua New Guinea has delivered positive results. Kora and the Irumafimpa deposit, where operations recently recommenced, comprise the Kainantu project.
The PEA process has been undertaken concurrent with the restart process at Irumafimpa.
K92 engaged Mincore Pty Ltd to complete a scoping study for expansion of the existing processing plant to double annual capacity to approximately 400,000 tonnes.
The study found that the current crushing, milling and concentrate handling circuits have sufficient capacity to treat the Kora ore at an annual rate of 400,000 tonnes, subject to upgrading the flotation circuit and plant services. The estimated total cost of such expansion and upgrading would be US$3.3 million, including EPC and commissioning with a contingency of 10%.
The company engaged Australian Mine and Development Pty Ltd (AMDAD) to undertake the PEA and a mine plan for Kora, which involved:
- Applying financial and processing parameters to determine cut off grades for stope design.
- Generating 3D stope shapes and mining inventory using the CAE Mineable Shape Optimiser (MSO) program.
- Creating a conceptual development layout to suit the MSO inventory.
- Producing a project cash-flow model.
- Producing a simple mining schedule as input to the cash-flow model.
AMDAD’s conceptual mine plan makes use of two proposed exploration inclines to be mined to the south of Irumafimpa. However, the mine plan assumes that these drives are a ‘sunk’ cost. The mine plan does not incorporate proposed Kora exploration drilling that will be undertaken from the Kora exploration inclines or any results from this work.
The key results from the Kora PEA are:
- Expected to have a 9-year operating life and treat 3.2 million tonnes @ 7.1 g/t gold, 25 g/t silver & 1.7% copper;
- Expected to generate an estimated positive cash flow to deliver a return of US$558 million using current metal prices;
- Expected to achieve an estimated pre-tax NPV of US$415 million using current metal prices, exchange rate and a 5% discount rate;
- Initial capital cost estimated to be US$13.84 million, including US$3.3 million for the plant upgrade identified in the Mincore study, but excluding the proposed Kora exploration inclines and diamond drilling;
- Sustaining Capital Cost estimated to be a further US$64 million spent over the life of Kora;
- Operating cost per ounce estimated to be US$125/tonne;
- Produce an estimated average of 108,000 gold equivalent ounces per annum over an 8-year period in years 2 through to 9; and
- Excludes approximately 1 million tonnes of unclassified material above 4.52 g/t gold in current resource model, which represents significant upside.
K92 is targeting production of 52,000 ounces gold equivalent from Irumafimpa in 2017 and targeting to commence production at a higher rate, at Kora in quarter 1 of 2018. Concurrent with production at Irumafimpa, an underground incline drive will be driven from Irumafimpa to Kora with expansion and exploration drill testing along the way.
K92’s CEO Ian Stalker said, “The Kora PEA indicates not only the opportunity of a fast lead into gold equivalent production levels in excess of 100,000 ounces per year, but also the potential of better than expected cash flow, lowest quartile all-in sustaining costs per ounce, low initial capital costs with a short payback period.
“It is also important to note that this PEA has been undertaken on the assumption that operations will ramp down at Irumafimpa once we commence production at Kora. While the proposed Kora operation reflects excellent economics, it is worth noting that production at Irumafimpa is targeted at $650 per ounce AISC and that at the proposed time for full production from Kora, there will still be circa 300,000 ounces in the mining inventory at Irumafimpa. Therefore, there remains potential to further enhance our current production expansion plans.
“In addition to evaluating the potential of continuing production at Irumafimpa once Kora is online, we will also be testing the Kora expansion potential by drilling from underground set ups, scheduled to commence in the first quarter of 2017. Kora is not only open in all directions, but is strongly mineralised at the extent of all drilling.
“K92 has an established team of mining professionals on the ground in PNG and it is reassuring that this team, who have now restarted Irumafimpa on-time and on-budget, will be guiding the rapid advancement of Kora.”
PNG is the region in focus in the quarter four edition of The ASIA Miner – read online.