Simberi is the northernmost island in the Tabar group of islands in the province of New Ireland – the easternmost province of Papua New Guinea (PNG) some 900 kilometres from the capital of PNG, Port Moresby.
Most of the island’s coast is steep (up to 300 metres in elevation) and surrounded by a fringing reef and deep plunging seawalls given the island’s volcanic origins. Rainfall is high throughout the year with a not so distinct wetter period from October through to April. Mean annual rainfall is 3 meters with monthly totals varying from 30mm to 600mm.
Access to Simberi is via a three hour charter flight from Port Moresby. Charter flights also stop at Kavieng (the capital of New Ireland province) and at Rabaul (in New Britain province). The 1400 metre airstrip is adjacent to the Piking Plantation some 3km from the process plant, and there is a 20metre long concrete wharf at Pigiput Bay. Fly-in fly-out staff and contractors stay at the 250-bed Pigiput camp.
There is evidence of very limited alluvial gold workings, probably dating from the 1920s, near the Matanabol Creek on Simberi. In 1982 Kennecott (later acquired by Rio Tinto), Nord Resources and Niugini Mining formed the Tabar JV to explore for gold on Simberi. In 1993 Nord acquired all the interests and undertook exploration and in 1996 commissioned a feasibility study which led to the grant of a Mining Lease (ML 126) in December 1996. As gold prices fell in 1997 the project was put on hold.
Allied Gold became involved in 2004 and reinstituted a feasibility study and by 2006 mine and mill construction commenced. In November 2007 mining operations began at the Samat East deposit and the first ore was processed in February 2008. Allied was acquired by St Barbara in September 2012.
Current mining occurs on the eastern half of the island covered by a 2,560 hectare Mining Lease (ML136). Ore at Simberi is sourced from a number of open pits. The Sorowar Pit is currently the largest defined oxide pit. Current mining plans of the oxide cap suggest a strip ratio of 1:1. Ore from the pits is delivered to the ROM pad (Sorowar feeder) where it is crushed and conveyed down an innovative and energy-efficient 2.7 km rope conveyor that transports the ore to a stockpile in front of the process plant.
Below the oxide pits on Simberi is a significant sulphide ore resource. In 2010 a prefeasibility study outlined the options for a 1.5 Mtpa sulphide circuit. A study is underway to examine alternatives for processing sulphide material.