A commitment to the highest standards of environmental monitoring and rehabilitation continues at Newcrest’s projects in the Gosowong area.
Toguraci Gold Mine
Toguraci is located 2 kilometres south-west of the original Gosowong pit on Halmahera Island in Indonesia. The project is operated by a joint venture company Pt Nusa Halmahera Minerals (PTNHM) which is 82.5 percent owned by Newcrest and 17.5 percent owned by PT Aneka Tambang.
The Toguraci open pit produced 79,493 ounces of gold during 2003/04 at a cash cost of production of $223 per ounce with a total cost of $280 per ounce.
Development of the mine commenced in July 2003 upon approval of the feasibility study and environmental impact statement by the Indonesian Minister of Mines. Site preparation, construction of the access road and pre-stripping activities were undertaken during the first six months, with mining of ore commencing and first gold production in February 2004. The orebody has performed in accordance with the geological model and all capital necessary to develop the project has been repaid.
Between late October and December 2003 up to 2,000 illegal miners occupied the Toguraci mine site. PTNHM suspended pre-stripping to ensure the safety of both staff and illegal miners. An Indonesian government committee was appointed to independently assess the occupation and PTNHM’s right to mine the deposit. The committee endorsed PTNHM’s right to mine and ordered the Indonesian police to remove the illegal miners.
Halmahera Island, Indonesia Open cut Gold Mine Nominal Treatment Rate 0.25 million tonnes pa 2004 Gold Production 79,493 ounces Cash Cost $223 per ounce Total Cost $280 per ounce *Gosowong Area Projects include the depleted Gosowong mine, Toguraci and the Kencana resource. |
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Since the operation commenced in 1998, PTNHM has maintained an ongoing commitment to various community development programs. During the year PTNHM provided funds for health care, educational support, training and fostering the establishment of local businesses.
The future of the Gosowong field lies in the Kencana project. At this stage, the Kencana project contains 1.1 million ounces of resource in high-grade mineralisation that remains open at depth and to the south. The project is 1 kilometre south of the existing mill and the mine is likely to be an underground operation. Kencana is expected to provide significant life to the Gosowong operations and to maintain continuous benefits to the surrounding region for a number of years.
A commitment to the highest standards of environmental monitoring and rehabilitation continues at Newcrest’s projects in the Gosowong area.
The rehabilitation of Gosowong’s waste dump and mined-out pit commenced immediately after mining was completed. In 2000, progressive rehabilitation of the waste dump began and currently about 45 percent has been revegetated.
The primary objective of the rehabilitation is to stabilise landforms quickly by establishing revegetation. The long-term objective is to re-establish a forest ecosystem similar to the original, limited production forest.
Rehabilitation success depends on several critical factors: correctly designed and constructed drainage, genuine stability, placement of clean subsoil and topsoil and maintenance after planting.
Three types of rehabilitation works are implemented: stabilisation, final rehabilitation and maintenance and repair.
As each part of the waste dump reaches its final form the surface is covered with approximately 20 centimetres of topsoil. Rapid site stabilisation can be achieved through the establishment of grasses and legumes.
The rapid establishment of ground cover and, over a longer period, a forest ecosystem, must be achieved in final rehabilitation. Planting is a two-stage process. Initially the priority is to establish a canopy cover (using pioneer tree species) to minimise erosion from rain and to provide a microclimate amenable to the establishment of rainforest tree species (native local species). The planting density is approximately 1,000 trees per hectare. Exotic legumes used as cover crop are chosen for their rapid growth and proven beneficial effects on soil fertility. Within 12 months the canopy development is usually sufficient to plant rainforest plants.
The monitoring of rehabilitation areas is undertaken to measure growth rates and establishment success of the species used. Monitoring can show that end-use criteria have been met and that the rehabilitated area is suitable to hand back to the Government and community.