Diamonds Tapajós The Tapajos is known worldwide for housing the largest auriferous province of Brazil. It was gold that attracted millions of miners past 46 years, like ants, created thousands of mines in the jungle. It was gold that attracted mining companies have discovered major deposits in the region. And the gold that was developed as the major regional centers Itaituba. However it is the diamond that is adding a new dimension to the goldfields of the Tapajós. Diamonds are not rare in the history of the Amazon. Important occurrences of diamonds were mined over time in the Rio Tocantins, south and north of Maraba, in the Xingu east of Altamira, and Waterfall Porteira the banks of the River Mapuera. Large companies such as Rio Tinto and De Beers invested large sums behind the primary sources of diamond. In the 90 Rio Tinto has covered a good part of the Tapajós with geophysical surveys and follow-ups from sediments of streams for the identification of diamonds and minerals satellite kimberlites and lamproites. The work of the Rio Tinto showed some interesting occurrences of diamonds and the discovery of kimberlites and some lamproíticos bodies. The indicator minerals, which were formed at great depths within the diamond stability field, were scarcely found. Are these indicators along with the diamond itself that really matter to the exploration geologist. At the time Rio Tinto considered the fact that the Tapajós be in a region affected by a strong Proterozoic magmatism, the Uatumã as a negative point. After the magmatism that could have heated crustal region impeding the development of primary diamond deposits. The Tapajos was placed on second priority, and the company never returned, closing all major projects to prospect a few years later. Even in the 90 miners discovered diamonds in a gold mine in Waterfall Porteira and later sediments southeast of Itaituba. Was when it was first explored the mining of diamonds in the Tapajos, the trigger of the discoveries that followed. What no one knew is that a good portion of the alluvium that were already being mined for gold, too, contained thousands of carats of high quality diamonds. Gradually some smarter miners began to adapt their older boxes (sluice boxes) to, well, the recovery of diamonds. The experiment was successful and the findings began to appear, especially in the interfluve Jamanxim and Tapajós. The news attracted prospectors of Mato Grosso, accustomed to plowing large volume, with much heavier than those used in the Tapajós equipment. This new invasion also brought experienced miners Juína the diamond region, which had been through a cycle of mining diamonds. Soon, foreign miners from Israel also began to invest in research and prospecting of diamonds Tapajós. The current frame is formed. With this number the Tapajós started producing, besides gold, thousands of carats of diamonds (official) week that sharpen the greed of many attracting a large number of prospectors and miners more foreigners. There are now more than 2,000 PCs, large backhoes, who do the work of dozens of miners in a few minutes it is estimated. The excavation and removal of soil, usually manual, have been made by increasingly larger equipment. Large rivers such as the Tapajós are being invaded by giant barges Suction, 18 inch, true monsters who suck million cubic meters of sediments rich in gold and diamonds from the bottom of rivers. These rafts are manufactured in Rondônia and use of 400HP engines, reaching cost US $ 1.2 million each. Some have been adapted with boxes for the retention of diamonds (pictured). These gigantic devices can only be used for really rich areas, it has a very high operating cost, over 50 grams of gold equivalent per day. The invasion of big equipment demonstrates in practice, the richness of the alluvial deposits that are being mined. Would now be the first discovered primary diamond deposits in the Tapajós? According to current geological knowledge the region has great potential for primary bentonite deposits. There is still an old, cold and stable craton as those that exist in virtually every region where the rich kimberlites are found. Another point that endorses this negative hypothesis is the near absence of low quality diamonds. The vast majority of diamonds are gem quality Tapajós: good news for miners. This indicates that the diamonds were transported long distances. During this transport the stones of lower quality, more brittle, break and virtually disappear. This is the explanation for the excellent quality of the diamonds off the coast of Namibia, which were transported by the Orange River for hundreds to thousands of kilometers. Maybe thats why they are not found minerals as common fragile satellites nearby kimberlites. With or without nearby primary sources diamonds from the Tapajós already part of the history of the region. They should change even more, the profile of miners and to the community. Soon we will see the installation of large washing plants equipped with high recovery equipment as sortex. This will be the moment that professionalism will take over and begin the diamond, actually, to be recovered in the Tapajós. Meanwhile, in Itaituba, motivated by the production of diamonds, a local councilor has preached that all diamonds must be locally polished before leaving the Tapajós ... Really, the diamond came to change. Source: geologo.br # TNT
Posted on: Thu, 06 Nov 2014 17:41:11 +0000
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