Tuesday, September 20, 2011

Gold Prospect in Bombana, Southeast Sulawesi

A gold panning boom occurred mid 2008 in Bombana, Southeast Sulawesi, marked by the discovery of nuggets by the local community in areas surrounding Tahi Ite. This discovery led to the massive influx of gold panners, both from the local communities and outside Bomabana, even from outside Sulawesi.

Apart from its positive impacts on the local community, gold alluvial panning by the people in Rarowatu and North Rarowatu districts, Bomabana will also create social, administrative, technical, and environmental issues.

The exploding amount of gold opportunists will eventually create social issues concerning land ownership and use of road access, environmental issues which includes rapid deforestation, and administrative issues concerning permits and regional income.

For these reasons alone, gold panning in the area must be controlled and managed correctly. Gold prospecting activities carried out by a group from the Mineral Research Program Group, of the Geological Body aims to map out the locations of gold deposits in the area, which may then be used as a technical reference for the local government in managing the area and issuing permits.

Prospecting activities is carried out by geological mapping methods, alluvial sediment mapping, geochemical and heavy mineral concentrate sampling. The prospected areas include the districts of North Poleang, Rarowatu, and North Rarowatu, which are all located within the regency of Bombana, Southeast Sulawesi.

Prospect Outcome

As many as 20 active river sediment samples, 73 concentrates, and 20 rock samples were examined in laboratories for their geochemical, mineralogy, petrography, and mineragraphy properties. The concentrates observed contained traces of gold ranging from fine to coarse sediment traces. These gold sediments are found in oxidized schist rocks and alluviums in loose materials, clays, and overburden.

After researching a total area of 31.790 Ha, the prospecting team has found that there are two types of gold sediments, primary sediment which is found in schist rocks (oxidation) and secondary sediments in alluvium areas. The minimum and maximum amounts of gold discovered ranges from 0,16405 g/m³ to 22,12 g/m³ respectively, with a minimum amount of secondary gold at 196,53 kg and a maximum of 26,499,76 kg (equivalent to 26,50 tons).

Alluvial gold deposits in the area may be exploited by local communities through a local panning process in rivers which originated from Tangkeno Wumbubangka hill. Alluvium gold sediments in oxidized schist rocks may also be exploited through a medium-scale mining process by means of mechanical equipments, while preserving the environment.

Detailed geological mapping is required in order to observe the spread of modified schist rocks, which is the main source of primary gold minerals. (KO/TC)


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