Wednesday, October 12, 2011

Gold Prospecting in Bombana Regency, Province of South East Sulawesi

Beside  providing income for the people of Rarowatu and Rarowatu North  districts, Regency of Bombana, alluvial gold panning by local communities in the area is also creates social problems, such as:  administrative , technical  and local environment problems, so that it is necessary to supervise and control  the management of mining activities in the area.

Prospecting activities  in the area are conducted to determine the distribution and resources of gold deposits in the area with the purpose to provide technical input to the local district government.

These activities are carried out with geological mapping methods, such as mapping of alluvial deposits, geochemical and heavy mineral concentrate samplings  and laboratory analysis of 20 active river sediment samples, 73 samples of concentrate and 20 rock samples platter.

Chemical analysis of rocks samples vary from : Cu = 5-72 ppm, Pb = 18-4160 ppm, Zn = 56-177 ppm, Ag = 0.5 - 5 ppm and Au = 18-172 ppb; whilst  stream sediment samples have values range of Cu = 20-30 ppm, Pb = 9-54 ppm, Zn = 5-95 ppm, Ag = 0.5 - 1 ppm and Au = 3-30 ppb. Mineralogical analysis of grain concentrate platter shows the value varies between 0.0026 g/m3 once to 22.12 g/m3. All of gold  grains   from concentrate platter are found in the northern part of the Tangkeno, Wumbubangka hills.

Two types of gold deposits are found in the area, namely  primary gold deposits in rock schist units which were further oxidize and  resulting an  enrichment of gold, and placer deposits in  alluvium unit.  The mineral resources of gold deposits  in  alluvium unit is 196,53 - 26.499,76 kg or equivalent to 26.50 tons. 


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