The area subject of the Exploration Licences has been extensively explored and studied by the Wafi-Golpu Joint Venture and its predecessors (EL 440 was granted on 11 March 1980 and EL 1105 was granted on 26 January 1995). The Wafi-Golpu Joint Venture and its predecessors, holders of the Exploration Licences have undertaken extensive investigations and studies to determine the feasibility of developing, mining and processing mineral deposits within the area the subject of the Exploration Licences.
The Project encompasses a mineralised porphyry intrusive that contains three separate but genetically related deposits namely: Nambonga, a mineralised copper-gold quartz vein array; Wafi, a high sulphidation epithermal gold deposit, and Golpu, a mineralised multiphase porphyry style copper-gold deposit. Of these the current focus is on the Golpu porphyry, the most advanced and economically significant of these deposits
The WGJV’s current focus is on the massive Golpu porphyry, the most advanced and economically significant of these deposits. The Pre-Feasibility and Feasibility studies completed in 2016 support the viability of construction and operation of a long life underground copper-gold mine. In 2016 and 2017 the Project remained the subject of further data collection and technical assessment with a Feasibility Study Update due to be completed in CY2018.
Feasibility study work undertaken to date proposes the development of twin exploration access declines, to access the orebody in which two block caves and associated services and infrastructure are to be developed to extract approximately 40% of the contained metal (gold and copper) of the Golpu ore reserve. The approximate 60% remaining ore reserve would be extracted by a future deeper block cave.
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 has 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 Lae Port Facilities Area
- Concentrate Filtration and Export – The proposed location of the filtration plant and associated materials handling and ship loading is located within the existing PNG Ports – Lae Port Facilities Area in close proximity to the Markham River estuary on the Huon Gulf.
Project development is likely to comprise of three activity phases:
- Construction of an underground mine and ancillary infrastructure, including declines development, ore processing, tailings management, concentrate transport/handling facilities and other related ancillary infrastructure
- Operation of the mine and ancillary infrastructure commencing at an initial production rate which will then be increased over time as more block caves are established.
- Closure of the mine and ancillary infrastructure, including rehabilitation at the end of the Life of Mine.
There are numerous villages in the vicinity of the Project Area, most commonly near rivers. Those villages in the Mine Area are inhabited by the Babuaf, Hengambu and Yanta people, while communities on the Lower Watut and Markham rivers are generally occupied by the Wampar people. Land remains in customary ownership, although there are disputes over land ownership boundaries in some places. The population of the Babuaf, Hengambu and Yanta villages is approximately 3,500, while a further 7,200 people live in the surrounding villages, including along the existing Demakwa Access Road.
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.
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 Newcrest Mining Limited and Harmony Gold Mining Company Limited.