Golpu Studies Support Two-stage Block Cave Development


Drilling activity at the Golpu project in Papua New Guinea. The
gold-copper property is jointly owned by Harmony Gold and Newcrest
Mining. (Photo: Newcrest Mining)
Harmony Gold has reported the results of feasibility and prefeasibility studies for Stages 1 and 2, respectively, of its jointventure Golpu gold-copper project in Papua New Guinea. Harmony and Newcrest Mining each currently own 50% of Golpu through their Wafi-Golpu joint venture. The Papua New Guinea government retains the right to purchase for its pro-rata share of historical costs up to a 30% equity interest at any time before the commencement of mining. If the government chooses to take up its full 30% interest, the interests of Harmony and Newcrest will become 35% each.

The Golpu deposit is located approximately 65 km southwest of the port city of Lae on Papua New Guinea’s east coast. Stage 1 of Golpu development focuses on the mining of two block caves, along with all associated infrastructure. Stage 2 contemplates a third, deeper block cave.

Stage 1 project capital is estimated at $2.6 billion. Plant throughput capacity is planned at 7 million metric tons per year (mt/y), with potential for a doubling to 14 million mt/y during Stage 2.

Stage 1 mine life is estimated at 28 years, producing a total of 3.6 million oz of gold and 2.2 million mt of copper in concentrates. At peak production, the mine would produce 297,000 oz/y of gold and 135,000 mt/y of copper in concentrates.

Golpu mineral resources, as of December 31, totaled 820 million mt, containing 18.6 million oz of gold at a grade of 0.70 g/mt, 8.6 million mt of copper at a grade of 1.0% copper, 33.1 million oz of silver at a grade of 1.3 g/mt, and 74,000 mt of molybdenum at a grade of 90 ppm.

Harmony is undertaking additional work to optimize the Golpu Stage 1 feasibility study, including the driving of two access declines toward the orebody to create drilling platforms required to verify geotechnical and hydrological interpretations of the orebody at depth.

Further investigation and modeling of water will focus on increasing the confidence in the geohydrology model by obtaining additional data from drilling campaigns, modeling the effectiveness of a dewatering bore field around the block cave subsidence zone, and streamflow and surface hydrology modeling and management.

The Golpu project can only progress to execution upon the granting of a special mining lease, which will include all necessary permits, approvals, and consents required by the Papua New Guinea government, landowners, and other relevant stakeholders. Assuming all such approvals are obtained, the feasibility study estimates that project development will require five years from the start of earthworks to first ore milled and that another 2.5 years will be required to reach steady-state production.

As featured in Womp 2016 Vol 03 - www.womp-int.com