LGL’s flagship gold project is the 100% owned operation located on Lihir Island in New Ireland province of Papua New Guinea.

The mine consists of a single ore body with three linked open pits that will be mined over the project life. The operation is currently focused on the processing of approximately 6 million tonnes of ore, with around 4 to 6 million tonnes of lower grade ore stockpiled annually. The mine currently has 28.8 million ounces in reserves and 43 million ounces in measured and indicated resources. 

 Download the Lihir Island Fact Sheet (308 KB)

Geology

Epithermal sulphide ore in an inactive volcanic crater.

Mine Production

Approximately 50 million tonnes of material is moved from the pit each year. Of this total, approximately 10 million tonnes is ore, of which around 4 million tonnes is stockpiled for future processing. The remaining 40 million tonnes is waste. Mining of the deposit is planned to continue until around 2023, after which time ore will be reclaimed from the stockpiles and processed for at least a further decade.

The remaining life-of-mine strip ratio is about 4:1 (waste: high-grade ore + low-grade ore).

Pit Dimensions

The planned final dimension of the pit is approximately 2 kilometres x 1.4 kilometres, with a final depth of 200 metres below sea level. Bench heights: 12 metres and 6 metres. Maximum final pit slope angle: 47°.

Processing

Ore from the Lihir Island mine is refractory, which means it requires pressure oxidation using autoclaves to release the gold. The plant's facilities first crush and grind the ore, and a flotation plant is used to concentrate a portion of the material as required, before it is fed to the autoclaves for pressure oxidation followed by conventional CIL technology. The process plant is currently capable of treating over six million tonnes of ore per annum with the capacity to produce in excess of 800,000 ounces of gold per year at the current gold grade.

Million Ounce Plant Upgrade

In 2008 LGL approved a major expansion to the Lihir process plant to increase annual gold processing capacity to approximately one million ounces per year. The project is focused on the installation of an additional autoclave to the process plant that is of a wider diameter and double the capacity of each of the three existing autoclaves. Annual throughput will increase to a maximum of around 11 to 12 million tonnes, lifting gold production by up to 240,000 ounces per year. Construction of the expansion commenced in 2008, with the new infrastructure scheduled to be in full operation during 2012. Click here for more information on the MOPU project.

Geothermal

The Lihir Island operation is located within a geothermally active area that produces a natural abundance of geothermal steam. Since 2003 LGL has been harnessing this underground steam reserve to generate electricity, replacing heavy fuel oil powered electricity. In February 2007 a new 20 Megawatt (MW) plant was commissioned, which lifts the operation's total geothermal capacity to 56MW - approximately 75 percent of total electrical power requirements in 2007. Drilling to assess the potential for additional steam reserves for further geothermal power capacity expansions continues to be undertaken. Geothermal power offers LGL significant cost savings compared to the cost of heavy fuel oil powered generation. The geothermal plant is also formally certified as a facility that will lead to reductions in greenhouse gas emissions, enabling the company to generate carbon credits and sell them on global markets.

Geography

Latitude: 3° 07' S;
Longitude: 152° 38' E.
Elevation: approximately 50 metres above sea level.
Temperature range: +19° Celcius to +35° Celcius.
Precipitation average: 4,800 millimetres per year.