Joint Interpretation of Core Samples and Well Logs to Define Lithological Contacts in Capanema Mine - MG, Brazil

A test site was built at the VALE Company to calibrate geophysical well logs acquisition, in order to collect more accurate data and know better the lithological units in three drill holes chosen in Capanema Mine - Brazil. This was made comparing geological contacts identified by descriptions of core samples with those defined by well logs. Thus, the main interest of the study was to seek on compositional and textural variations of iron formations caused by changes in moisture and hardness of the rocks. The methodology has proved satisfactory in order to detect the presence of clay and hydrated bodies, as well as the transition between friable and compact itabirites. Therefore, the results open up possibilities to changes exploratory drilling meshes with partial replacement of core sampling by rotary percussive boreholes. This allows to do a mineral exploration with lower costs using a faster and cheaper technique, but always using well logs to support the geological interpretation in subsurface.