THE historic Kainantu gold project in the Eastern Highlands Province is back after new operator K92 Mining Inc. announced it had successfully started gold production from the Irumafimpa gold deposit.
Canada-headquartered K92 purchased the Kainantu gold project from Barrick Gold Corp. in 2015 and has built a strong PNG team to help develop the high grade gold riches in the area.
The initial resource estimate for the Kora and Irumafimpa deposits near Kainantu, situated within the company’s Mining Licence ML 150, is 1.84 million inferred oz. at 11.6 g/t Au eq. and 240,000 indicated ounces. at 13.3 g/t Au eq .
The company’s CEO, Ian Stalker, said the start-up of production was a highly significant milestone for the company, and for this region of PNG.
“A great deal of thanks goes to the entire team on site in PNG in achieving production ahead of schedule and on budget.”
That work has included the rehabilitation of the Irumafimpa Gold Mine, process plant and associated infrastructure, an enhancement of the processing facility including the installation of a new Drum Scrubber.
K92 has also enhanced the existing underground mobile plant fleet including receiving onsite delivery of trucks, LHDs, jumbo and stope drills.
“With mining at Irumafimpa and processing now commenced, we are now well positioned to evaluate and advance production expansion opportunities that exist within our Mining Lease ML150 including potential at the Kora gold deposit,” Stalker said.
Kora potential revealed
K92 has already had some significant success with its Kora activity, recently reporting the results of a Preliminary Economic Assessment (PEA), with the PEA process undertaken concurrently with the restart process at Irumafimpa.
At Kora the company engaged Mincore Pty Ltd to complete a scoping study for the expansion of the existing processing plant to double its capacity to approximately 400,000 tonnes per annum.
K92 said the study found that the current crushing, milling and concentrate handling circuits have sufficient capacity to treat the Kora ore at a rate of 400,000 tpa, 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 also 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 three-dimensional 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.
The conceptual mine plan prepared by AMDAD makes use of two proposed exploration inclines to be mined to the south from 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.
K92 said the key results from the Kora PEA are as follows:
- expected to have a nine year operating life and treat 3.2 Million tonnes @ 7.1 g/t Au, 25 g/t Ag & 1.7% Cu (9.3 g/t Au Eq);
- 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 Scoping 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
- Cash Cost estimated to be US$547/oz Au Eq (inclusive of a 2.5% NSR) and AISC of US$619/oz Au Eq
- produce an estimated average of 108,000 Au Eq* ozs per annum over an 8 year period in years 2 through to 9;
- excludes approximately 1 Million tonnes of unclassified material above 4.52 g/t Au g/t in current resource model – which represents significant upside; and
- Current Metal Prices used were: Au – US$1,300/oz; Ag – US$18/oz; Cu – US$4,800/tonne.
The company said the PEA is preliminary in nature and includes inferred mineral resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorised as mineral reserves, and there is no certainty that the PEA will be realized.
K92 is targeting production of 52,000 ounces Au Eq from Irumafimpa in 2017 and targeting to commence production at a higher rate at Kora in Q1 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.
The initial resource estimate for Kora, situated within the company’s Mining License 150, is 1.65 M inferred oz. at 11.6 g/t Au Eq. Kora remains open in all directions and strongly mineralised at the extent of drilling.
“This 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,” Mr Stalker said.
“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 US$650 per oz 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 1st 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,” Mr Stalker said.