Simberi Island
Encyclopedia
Simberi Island is a volcanic island in the Tabar Group
, in Papua New Guinea
's New Ireland Province.
together with a series of small islets. There is a barrier reef about 10 km offshore from the west coast. A 2 km strait separates Simberi from Tatau Island to the south west.
Simberi island is a potassium
rich (high-K) calc-alkaline
island arc
volcano, the oldest in the Pliocene
to Holocene
Tabar-Lihir-Tanga-Feni (TLTF) volcanic arc
that formed above a subduction zone
.
(also known as Tabar), ISO 639-3
language code "tbf", an Austronesian language spoken on the Tabar Islands.
"NIS"), on the south east coast.
, an Australian based company, operate an open pit
gold (and silver) mine
called the Simberi Oxide Gold Project in the volcanic highlands on the eastern side of the island. The mine is wholly owned and operated by Allied Gold. Gold production started in February 2008. Mining was suspended in December 2009 after Allied Gold received a cease work order from the Mineral Resources Association of Papua New Guinea because of local landholder issues. Mining has since recommenced.
Seven gold deposits have been defined in mining lease 136 (ML 136), which covers the central and eastern portion of Simberi Island, and other prospects have been identified. The gold deposits occur mainly on ridge tops and are all within 2 to 3 km of each other. Sorowar in the north is the largest resource while Samat North, South and East to the south are relatively small but relatively high grade. Pigiput, Pigibo and Botlu South lie between the Sorowar and Samat areas and are of intermediate tonnage but at a grade similar to Sorowar. The western area of Simberi Island within exploration license EL 609 is largely unexplored. Reconnaissance exploration for both oxide and sulphide mineralisation is planned.
As of June 2009, Allied reported that the total resources were 4.7 million ounce
s (Moz) gold, being oxide gold resources of 1.4 Moz and sulphide gold resources of 3.3 Moz together with 10.2 Moz silver.
Ore is delivered to the processing facilities on the eastern coast near Pigiput Bay by a 2,665 m long RopeCon aerial conveyor that can deliver 600 tonnes of ore per hour. The process plant is a conventional carbon-in-leach (CIL) gold process plant capable of treating 2.2 million tonnes of ore per year. In September 2010, Allied announced that it planned to increase its gold production to 100,000 oz per year. The oxide processing circuit at the Simberi operation will be expanded to 3.5-million tonnes a year, by December 2011.
Mine tailings
are disposed of in the form of a slurry that has been pre-diluted with seawater using a deep sea tailings pipeline. The pipeline is 528 m long with the discharge point at a depth of 130 m. The tailings flow down a steep submarine slope and are deposited at a depth of more than 3 kilometers.
Production for the period from 1 July 2009 to 30 June 2010 was 64,327 oz.
In June 2009, Allied reported that the remaining mine life was estimated to be over 10 years. Allied Gold are the largest employer on the island.
Tabar Group
The Tabar Group is an island group in Papua New Guinea, located 40 km north of New Ireland. It is a part of the Bismarck Archipelago. The Tabar group consists of a short chain of three main islands - Tabar Island in the south, Tatau Island in the center, and Simberi Island in the north - as...
, in Papua New Guinea
Papua New Guinea
Papua New Guinea , officially the Independent State of Papua New Guinea, is a country in Oceania, occupying the eastern half of the island of New Guinea and numerous offshore islands...
's New Ireland Province.
Geography and geology
Simberi is the northern most and smallest of the three islands in the Tabar Group. The island is about 9 km long and 7 km wide and has an area of about 40 square kilometers. Its highest point in the highlands on the eastern side of the island is a 340 m eroded volcanic cone. The interior of the island is largely covered by rainforest. Most of the island's coast is steep and surrounded by a fringing reefFringing reef
A fringing reef is one of the three main types of coral reefs recognized by most coral reef scientists. It is distinguished from the other two main types in that it has either an entirely shallow backreef zone or none at all...
together with a series of small islets. There is a barrier reef about 10 km offshore from the west coast. A 2 km strait separates Simberi from Tatau Island to the south west.
Simberi island is a potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
rich (high-K) calc-alkaline
Calc-alkaline
The calc-alkaline magma series is one of two main magma series in igneous rocks, the other magma series being the tholeiitic. A magma series is a series of compositions that describes the evolution of a mafic magma, which is high in magnesium and iron and produces basalt or gabbro, as it...
island arc
Island arc
An island arc is a type of archipelago composed of a chain of volcanoes which alignment is arc-shaped, and which are situated parallel and close to a boundary between two converging tectonic plates....
volcano, the oldest in the Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
to Holocene
Holocene
The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...
Tabar-Lihir-Tanga-Feni (TLTF) volcanic arc
Volcanic arc
A volcanic arc is a chain of volcanoes positioned in an arc shape as seen from above. Offshore volcanoes form islands, resulting in a volcanic island arc. Generally they result from the subduction of an oceanic tectonic plate under another tectonic plate, and often parallel an oceanic trench...
that formed above a subduction zone
Subduction
In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. These 3D regions of mantle downwellings are known as "Subduction Zones"...
.
People
The population is about 1100 and made up of nine clans who live in small coastal villages mainly in the north and west. The local language is a Simberi dialect of MandaraMandara language
Mandara is an Austronesian language spoken on the Tabar Group of islands, New Ireland Province, Papua New Guinea. Three dialects have been identified, Simberi, Tatau and Tabar, corresponding to the three main islands in the group....
(also known as Tabar), ISO 639-3
ISO 639-3
ISO 639-3:2007, Codes for the representation of names of languages — Part 3: Alpha-3 code for comprehensive coverage of languages, is an international standard for language codes in the ISO 639 series. The standard describes three‐letter codes for identifying languages. It extends the ISO 639-2...
language code "tbf", an Austronesian language spoken on the Tabar Islands.
Transport
The island has an airport, Simberi Airport (IATA airport codeIATA airport code
An IATA airport code, also known an IATA location identifier, IATA station code or simply a location identifier, is a three-letter code designating many airports around the world, defined by the International Air Transport Association...
"NIS"), on the south east coast.
Simberi Oxide Gold Project
Allied GoldAllied Gold
Allied Gold Mining PLC , is an Australian based Pacific Rim gold producer with gold production, exploration and development projects in Papua New Guinea and the Solomon Islands...
, an Australian based company, operate an open pit
Open-pit mining
Open-pit mining or opencast mining refers to a method of extracting rock or minerals from the earth by their removal from an open pit or borrow....
gold (and silver) mine
Gold mining
Gold mining is the removal of gold from the ground. There are several techniques and processes by which gold may be extracted from the earth.-History:...
called the Simberi Oxide Gold Project in the volcanic highlands on the eastern side of the island. The mine is wholly owned and operated by Allied Gold. Gold production started in February 2008. Mining was suspended in December 2009 after Allied Gold received a cease work order from the Mineral Resources Association of Papua New Guinea because of local landholder issues. Mining has since recommenced.
Seven gold deposits have been defined in mining lease 136 (ML 136), which covers the central and eastern portion of Simberi Island, and other prospects have been identified. The gold deposits occur mainly on ridge tops and are all within 2 to 3 km of each other. Sorowar in the north is the largest resource while Samat North, South and East to the south are relatively small but relatively high grade. Pigiput, Pigibo and Botlu South lie between the Sorowar and Samat areas and are of intermediate tonnage but at a grade similar to Sorowar. The western area of Simberi Island within exploration license EL 609 is largely unexplored. Reconnaissance exploration for both oxide and sulphide mineralisation is planned.
As of June 2009, Allied reported that the total resources were 4.7 million ounce
Troy ounce
The troy ounce is a unit of imperial measure. In the present day it is most commonly used to gauge the weight of precious metals. One troy ounce is nowadays defined as exactly 0.0311034768 kg = 31.1034768 g. There are approximately 32.1507466 troy oz in 1 kg...
s (Moz) gold, being oxide gold resources of 1.4 Moz and sulphide gold resources of 3.3 Moz together with 10.2 Moz silver.
Ore is delivered to the processing facilities on the eastern coast near Pigiput Bay by a 2,665 m long RopeCon aerial conveyor that can deliver 600 tonnes of ore per hour. The process plant is a conventional carbon-in-leach (CIL) gold process plant capable of treating 2.2 million tonnes of ore per year. In September 2010, Allied announced that it planned to increase its gold production to 100,000 oz per year. The oxide processing circuit at the Simberi operation will be expanded to 3.5-million tonnes a year, by December 2011.
Mine tailings
Tailings
Tailings, also called mine dumps, slimes, tails, leach residue, or slickens, are the materials left over after the process of separating the valuable fraction from the uneconomic fraction of an ore...
are disposed of in the form of a slurry that has been pre-diluted with seawater using a deep sea tailings pipeline. The pipeline is 528 m long with the discharge point at a depth of 130 m. The tailings flow down a steep submarine slope and are deposited at a depth of more than 3 kilometers.
Production for the period from 1 July 2009 to 30 June 2010 was 64,327 oz.
In June 2009, Allied reported that the remaining mine life was estimated to be over 10 years. Allied Gold are the largest employer on the island.