PROSPECÇÃO E ECONOMIA DO DIAMANTE DA SERRA DO ESPINHAÇO

Résumé

Diamond occurs in the Espinhaço range both in alluvials and in Midproterozoic metaconglomerates.In the alluvials they are recovered by large bucket wheel dredges as well as by more artisanal hydraulicgravel-pump mining. The “Sopa” metaconglomerates were mined out in the past wherever they wereheavily weathered into very soft material amenable to artisanal hydraulic gravel pump mining.This short paper describes the main geologic features which should be considered in the study of amining project on deposits of one of these two types.An attempt is also made at giving an insight into the future of the region’s diamond mining activityconsidering that its alluvials will be exhausted in the next decade. The discovery of new deposits of thesoft metaconglomerate type - and for this sake of their kimberlitic sources - depends largely on whichgeologic model is adopted. Various models have been proposed by different authors including the riftmodel, put forward by the present author. each model will justify the adoption of a different explorationapproach.Finally, the possibility of reactivating the diamond mining industry in the region through the designof an appropriate treatment process for the recovery of the gem from the metaconglomerates of the hardsilicified facies, known as “massa gelada”, is also envisaged.