The Project region has been extensively explored and studied by the Wafi-Golpu Joint Venture and its predecessors. EL440 was granted on 11 March 1980 and EL1105 was granted on 26 January 1995 and, since its formation in 2008, the Wafi-Golpu Joint Venture has undertaken extensive investigations and studies of the area the subject of the Exploration Licences to determine the feasibility of developing, mining and processing mineral deposits within the area.
The Exploration Licences encompass a mineralised porphyry intrusive that contains three separate but genetically related deposits namely: Golpu, a mineralised multiphase porphyry style copper-gold deposit; Nambonga, a mineralised copper-gold quartz vein array; and Wafi, a high sulphidation epithermal gold deposit.
The WGJV’s current focus is on the massive Golpu porphyry, the most advanced and economically significant of these deposits. Pre-Feasibility and Feasibility studies were completed in 2016 and supported the viability of construction and operation of a long life underground copper-gold mine. In 2016 and 2017 further data collection and technical assessment was undertaken, with a Feasibility Study Update completed in December 2017 and submitted to the Mineral Resources Authority in March 2018.
The Feasibility Study Update proposes the development of the Nambonga decline and twin underground access declines to access the orebody in which three block caves and associated services and infrastructure, including a portal terrace, the Watut Process Plant, power generation facilities, laydown areas, water treatment facilities, wastewater discharge and raw water make-up pipelines, raw water dam, sediment control structures, roads and accommodation facilities.
The proposed mining method is block caving, a technique using the controlled collapse of a near-vertical orebody as a means of breaking and extracting the ore. Block caving uses two or three levels (undercut, production/extraction and services/ore handling) as follows:
- ‘Undercut’ is the level at which the initial, once-off drilling and blasting takes place to shatter rock at the bottom of the orebody.
- ‘Production/Extraction’ is situated below the undercut level. This level is linked to the undercut by funnel-shaped excavations known as draw bells through which the broken rock descends. Ore is extracted by load-haul-dump (LHD) vehicles from a network of draw points. Because the ore in the undercut level is unsupported, once extraction starts, the collapse of the rock in the undercut will continue as long as extraction continues.
- ‘Services’ is the lowest level and may be used for ventilation and transport of ore to the surface.
The Project Area comprises three main areas of proposed activity:
- Mine Area – The proposed Mine Area is located on the northern side of the Owen Stanley Ranges of Papua New Guinea (PNG), approximately 65 kilometres (km) from the Port of Lae, in the foothills of the Watut River catchment. The elevation of the Mine Area ranges from approximately 100 metres above sea level (mASL) to 380Masl. Most of the Mine Area is steep and mountainous, and is covered by dense tropical rainforest.
- Infrastructure Corridor – The proposed infrastructure corridor is situated on the floodplains of the Watut and Markham rivers and includes the Mine Access Road. The proposed 32km long Northern Access Road connects the Mine Access Road to the Highlands Highway. A concentrate pipeline extends from the Mine Area to the Coastal Area.
- Coastal Area – The proposed Coastal Area includes the proposed Port Facilities Area and the proposed Outfall Area. The proposed location of the filtration plant and associated materials handling and ship loading facility is the Port of Lae and the Outfall System comprising the mix/de-aeration tank and associated facilities is located approximately 6 kilometres to the east of the Port, in close proximity to the Markham River estuary on the Huon Gulf.
On 25 August 2016 the Wafi-Golpu Joint Venture submitted a Special Mining Lease application to the Papua New Guinea Mineral Resources Authority. The Special Mining Lease application includes a Proposal for Development, which incorporates the 2016 Feasibility Study report and supporting application documents such as a National Content Plan.
Environmental approval for the Project is being sought under the PNG Environment Protection (Prescribed Activities) Regulation 2002. The required approval for the Project is a Level 3 Environment permit. On 25 June 2018, the Wafi-Golpu Joint Venture submitted an Environmental Impact Statement (EIS) to the Papua New Guinean regulatory authority, Conservation and Environment Protection Agency (CEPA).
Any potential future development of the Wafi-Golpu Project is subject to further studies, completion of statutory processes, receipt of all necessary or desirable Government permissions and approvals, market and operating conditions, and approval by the Board of Directors of both of the WGJV participants and of both Newcrest Mining Limited and Harmony Gold Mining Company Limited.