Dados da Submissão

Título

UNDERGROUND GEOLOGICAL MAPPING TECHNIQUES - A TOOL TO THE RECOGNITION OF GEOLOGY IN LAMEGO GOLD DEPOSIT

Texto do resumo

The Lamego orogenic gold deposit is located at the southwestern end of the Quadrilátero Ferrífero region, Brazil. These Archean orogenic gold deposits are situated in the Rio das Velhas greenstone belt with the lithological succession consisting of metamorphosed (greenschist facies) mafic volcanic rock, chert, and banded iron formation (BIF), carbonaceous and micaceous schists. The orebodies constitute the Lamego BIF, where gold-mineralized zones are related to iron-rich bands and associated silicification zones. Two different methods for the preparation of geological underground maps are here discussed and compared. In this study, we used these methods to produce and later compare two geological maps. In the Tradicional Method, the collected data were plotted on a topographic base map with local coordinates, which delimits the geometry of the underground gallery to be mapped. Topographic maps are generated through topographic surveys, which can be performed by total stations/theodolites or even using measuring tape and compasses. At the AngloGold Ashanti Córrego do Sítio Mineração, geological mapping is carried out using a technique that automates the traditional method previously approached. In a topographic base map with local coordinates, drilling holes, and channel samples are projected via Datamine Studio RM version 1.12 onto a projection plane. All channel samples are collected considering the contacts between lithotypes and/or mineralized zones and are later plotted on the projection plane according to the structure’s fold axis plunge. The traditional method was able to carry out the geological mapping of an area of 268 m2 and, in 12 hours, divided into 4 days of work. In comparison, the automated method performed the geological mapping of an area of 1647 m2, whose total process revolves around 3 hours over a day of work. Taking into account the production speed, the automated method is extremely more efficient, in terms of both speed and the mapped area covered. This results in extremely efficient production. The automated mapping generated an 84% larger mapped area in a 75% smaller dedication time. On the other hand, the traditional method demonstrated a greater control of geological detailing and a greater amount of structural measurements, given that when in fieldwork, the amount of concrete visualization of information is much greater.

Palavras Chave

Underground Geological Mapping; Geological Mapping; Orogenic Gold Deposit; Quadrilátero Ferrífero;