The overland conveyor at the Hidden Valley follows the site’s tourturous contours providing a vital link between the pit and processing plant.

Innovative Conveyor Upgrades Improve Safety and Throughput at PNG Gold Mine

Harmony Gold Mining Company Limited (“Harmony” and/or the “Company”) was first registered in 1950 with a single mine lease and poured its first gold in 1954. Harmony is a world-class gold mining and exploration company, with operations and assets in South Africa and Papua New Guinea (PNG). Harmony has close to 70 years’ experience in the industry, aiming to produce about 1.4 million ounces in financial year 2020.

Harmony’s assets include one open pit mine and several exploration tenements in PNG. The company also has 9 underground mines, 1 open pit operation and some surface sources in South Africa. Additionally, in a joint venture, Harmony owns 50% of the significant Wafi-Golpu copper-gold project in PNG – a tier 1 asset. 

Situated some 210 km northwest of Port Moresby, the Hidden Valley gold and silver mine is Harmony’s third largest operation.

Hidden Valley is an open pit mine, located in New Guinea’s high lying Morobe Province at an altitude of around 2500 metres. Access from Port Moresby involves a 45-minute domestic flight to a small airstrip near the town of Bulolo at an elevation of 700m, followed by a steep, 2-hour climb in a 4WD bus to the Hidden Valley mine site. The mine consists of three main lodes: Hidden Valley - Kaveroi (HVK), the two main lodes, mined as a single pit, and Hamata. The processing plant is located near the Hamata mining area.

The Kaveroi pit at the Hidden Valley gold mine.

Processing Business Unit Manager, Geoffrey Atkinson, is responsible for the mine’s processing and fixed plant maintenance. His 400 strong team maintains site services, as well as the operations - from primary crushing all the way through to processing and smelting. A veteran of the mining industry, Atkinson started his career as a tradesman fitter and has worked on all aspects of plant maintenance across Australia and New Guinea within a diverse range of commodities - gold, coal, silver, lead, zinc and uranium.

“Our mine has a target gold production of 190000 to 200,000 ounces per annum, which was achieved last year.” he said.

The Hidden Valley Kaveroi pit is located about 5km away from the processing plant which is situated adjacent to the Hamata orebody. There’s a steep and winding access road between the pit and plant that crosses the Watut River.

Because of the high annual rainfall (up to 3m pa) the river is subject to short flooding events. Operating heavily laden haul trucks along this road when it is wet is certainly not the preferred means of ore transportation.

The pit is also linked to the processing plant via a 5.4km overland pipe conveyor. ROM feed from Hidden Valley Kaveroi goes through two-stage crushing, before being transported by the conveyor onto the coarse ore stockpile at the processing plant. It then undergoes grinding, flotation, concentrated leach and CCD. Conventional gravity and CIL circuits are used for gold and a Merrill Crowe circuit for silver extraction.

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